- Email: [email protected]
Huge abdominal mass in a 69-year-old man
CLINICOPATHOLOGIC CONFERENCE
Huge Abdominal Mass in a 69-Year-Old Man
Stenographic reports of weekly clinicopathologic conferences held in Barnes and Wohl Hospitals are published in each issue of the Journal. Members of the Departments of Internal Medicine, Radiology, and Pathology of the Washington University School of Medicine participate jointly in these conferences. Kenneth M. Ludmerer, M.D., and John M. Kissane, M.D., are the editors of this feature. A 69-year-old black man was admitted to Barnes Hospital on August 8, 1984, for evaluation of abdominal distention. The patient had been well until IO days prior to admission, when mild dull pain in the left lower quadrant developed after sneezing. The pain persisted, and the next morning, he noted abdominal distention and generalized “soreness.” His stools became more frequent, of smaller caliber, and quite dark. The abdominal pain was intermittent, but the distention did not change. His appetite had been poor for two weeks. There was no fever, chills, nausea, vomiting, chest pain, jaundice, frank melena, or bright red rectal blood, Physical examination on admission revealed a temperature of 36.5OC, a blood pressure of 126/88 mm Hg (lying and standing), a pulse rate of 78 per minute (lying) and 96 per minute (standing), and a respiratory rate of 22 per minute. A 1 cm mobile, firm, right supraclavicular mass was present. The abdomen was protuberant, tense, and nontender with central dullness and surrounding tympany. A fluid wave, a left lower quadrant pulsatile sensation, and a reducible right inguinal hernia were noted. Rectal examination demonstrated increased tone, moderate tenderness, and a nodular prostate. The stool contained no occult blood. Results of laboratory evaluation included normal electrolyte and chemical values, except for a lactic dehydrogenase of 320 IL-f/liter. The hemoglobin level was 12.9 g/dl, the hematocrit 39.1 percent, and the white blood cell count 7,l 00/mm3. Results of urinalysis were unremarkable, and the serum amylase was 57 Ill/liter. Computed tomographic scanning of the abdomen demonstrated a large retroperitoneal cystic mass that was thought to be a pancreatic pseudocyst. Aspiration of the mass produced 2 liters of dark fluid, which contained a lactic dehydrogenase level of 3,980 It-f/liter, protein of 3.5 g/dl, amylase of 39 Ii-r/liter, total cell count of 123,220/mm3, and white blood ceil count of 1 ,321/mm3 (35 percent neutrophils). Cytologic examination of the fluid showed no abnormalities. Barium enema demonstrated downward displacement of the transverse colon by a large abdominal mass, with compression of the descending and sigmoid colon; there was no intrinsic
March
1966
The American
Journal
of Medicine
Volume
60
477
CPC-HUGE
ABDOMINAL
fgure 1. Anatomy text for discussion.
MASS
of certain abdominal
structures.
verse mesocolon to the retroperitoneum. The small bowel is connected by its mesentery to the retroperitoneum. The transverse mesocolon originates on top of the pancreas and just above the duodenum. From the radiographic evidence, either the lesion is in the omentum or transverse mesocolon, or else it is in the lesser sac between these two structures. The differential diagnosis will depend upon the location of the lesion. If the mass is in the lesser sac, we have to include processes that might involve the pancreas and duodenum. If it is in the transverse mesocolon or the omentum, it most likely represents some kind of cystic or tumorous lesion. An im~portant question is whether we can eliminate the pancreas from consideration. At this point I would like Dr. Levitt to review the radiographic findings. Dr. Robert Levitt: Computed tomographic examination of the abdomen was obtained upon admission. Scanning after intravenous injection of contrast material revealed a very large nonhomogeneous mass. This mass had a lowdensity central region surrounded by a thick wall. In the upper abdomen, the mass was situated between an anteriorly displaced stomach and a normal-sized pancreas (Figure 2). In the lower abdomen, the mass was situated anterior to the transverse colon (Figure 3). Serial computed tomography showed that the mass could have arisen from the retroperitoneum, greater omentum, or transverse mesocolon. Barium enema showed the mass displacing the transverse colon inferiorly, but the colon was intrinsically normal (Figure 4). On the second admission, 3 liters of serosanguinous fluid was drained from the mass percutaneously, and iodinated contrast material was instilled into the mass. A supine abdominal film showed that the instilled contrast material surrounded the transverse colon (Figure 5). On fluoroscopy, the contrast material appeared to be within the transverse mesocolon. Dr. Alpers: I spoke with the physician who performed the barium enema, and he said that he was impressed by the pattern of the barium fanning out into the transverse mesocolon, but we not have any pictures to demonstrate that. It is likely that there was blood in the center of the mass, and, as demonstrated by computed tomography, the mass had a thick wall. In addition, the blood level of lactic dehydrogenase was roughly 300 Ill/liter, whereas the lactic dehydrogenase level in fluid from the mass was nearly 4,000 Ill/liter. These observations suggest the possibility of a tumor. Let me first go through some things that I think the lesion is not We will start with lesions that are located in the lesser sac. Keep in mind that if the lesion originated from the lesser sac, it would have to burrow through the transverse mesocolon in order to end up anterior to the colon, as seen radiographically. That possibility seems unlikely to me. Nonetheless, the four lesionsto be consid-
See
colonic abnormality. The patient was discharged with anticipation of future laparotomy. The patient’s symptoms persisted, and he was readmitted to Barnes Hospital on September 4, 1984. Findings on physical examination were unchanged. The albumin level was 3.3 g/dl, lactic dehydrogenase 295 Ill/liter, acid phosphatase 0.24 Ill/liter (normal, less than 0.7 IMiter), and carcinoembryonic antigen 2.7 ng/dl (normal, less than 2.5 ng/dl). Aspiration removed 3 liters of serosanguinous fluid from the mass. The fluid cell count and chemical values were similar to those of the previous drainage procedure. Contrast medium was injected into the cavity, demonstrating that it lay superior and anterior to the transverse colon and medial to the splenic flexure. The cavity conformed to the expected configuration of the transverse mesocolon. Upper gastrointestinal series with small bowel follow-through demonstrated a mass effect, with displacement of the stomach, duodenum, jejunum, and colon at the splenic flexure. A procedure was performed. CLINICAL DISCUSSION Dr. David Alpers: There are two important aspects to this case. First, as far as the care of this patient is concerned, an operative procedure was mandatory. It was necessary to remove the cystic mass to discover its identity and resolve the patient’s symptoms. Second, the precise anatomic location of the lesion was important, to allow an intelligent guess concerning its nature. Let us consider the localization of the lesion. The stomach is suspended from the underside of the liver, and the greater curvature is extended by the omentum to the colon (Figure 1). The colon is connected by the trans-
478
March
1986
The
American
Journal
of Medicine
Volume
80
CPC-HUGE
ABDOMINAL
MASS
Figure 2. Computed tomographic scan through upper abdomen shows nonhomogeneous mass situated between air-filled stomach (s) and pancreas (arrows).
Figure 3. Computed tomographic scan through lower ab domen shows the mass is situated anterior to the transverse colon (arrows). The mass has a low-density central region surrounded by a thick wali.
Figure 4. Barium enema normal transverse colon.
Figure 5. Supine abdominal film after iodinated material was instilled into mass shows contrast collecting around transverse colon.
film showing
mass effect upon
March
1988
The American
Journal
of Medicine
Volume
contrast material
80
479
CPC-HUGE
ABDOMINAL
MASS
ered are a pancreatic pseudocyst, abscess, cystadenoma, and cystadenocarcinoma. We can quickly dismiss the pseudocyst and abscess, because the amylase level was not increased in the aspirated fluid. Moreover, there was very little inflammatory response in the cyst. There were 1,300 white blood cells, only 35 percent of which were polymorphonuclear leukocytes, and there was no fever or report of constitutional symptoms. All the findings expected with a pancreatic abscess were absent. When you add to this the fact that a location anterior to the colon is highly unusual for a pancreatic pseudocyst or abscess, we can eliminate these diagnoses. I would like to point out that this man was not an alcoholic and did not have biliary tract disease. In every series, a significant percentage (up to 50 percent, but usually around 10 or 20 percent) of cases of chronic pancreatitis are idiopathic. The absence of either alcoholism or cholecystitis does not, in any way, eliminate chronic pancreatitis. Still, these facts lessen the possibility of pseudocyst. Now as far as cystadenoma and cystadenocarcinoma are concerned, the two of them together represent about 1 percent of all pancreatic tumors. That does not argue against them in the differential diagnosis of this case, since the lesion is so unusual. These tumors account for about 10 percent of all pancreatic cystic lesions, simple cysts accounting for the rest. They usually occur in middle-aged females; in one series, 82 percent of them were in females [I]. They typically present with pain, nausea and vomiting, and weight loss-symptoms this man had. Frequently, there is associated pancreatitis, which he did not have. Only 10 percent of these lesions calcify, so the absence of calcification in this case is not a strong point against the diagnosis. The main argument against this diagnosis is the computed tomographic evidence, since cystadenomas usually present with numerous tiny, glycogen-filled cysts [2]. The cysts occur mostly in the body and the tail and can be as large as 30 cm in diameter. In this patient, scanning showed no evidence of such cysts. The scanning results also were not typical of cystadenocarcinomas, which are multiloculated and have mutinous fluid in the center. Now I would like to discuss lesions of the mesocolon and the omentum. Different types of tumors affect these two regions; they both can be involved by the same type of cysts. The developmental difference between these two structures is that, during its embryologic stages, the mesentery has cells that can differentiate into any type of mesenchymal cell. Thus, the mesentery can contain fibrous tissue, smooth muscle elements, lipomatous elements, and blood vessels, whereas the omentum is much more restricted and does not give rise to so many different varieties of tumors. Let us start with a discussion of cysts. I would preface these remarks by saying I think the lesion is unlikely to be
480
March
1988
The American
Journal
of Medicine
Volume
a cyst because the wall was so thick and because most cysts present in the fourth or fifth decades rather than at this patient’s age. Cysts are usually benign. They can enlarge very rapidly because of bleeding or torsion. Types of cysts include wolffian remnants of the genitourinary system, lymphatic cysts, mesocolic cysts (which are basically simple cysts of the mesocolon), dermoid cysts, and parasitic cysts. Lymphatic and mesocolic cysts are lined by simple epithelium and thus are very unlikely, unless this was a cyst in which inflammation or bleeding had gone on for such a long time that a thick wall was produced. With a dermoid cyst, some kind of irregularity of contour would be expected and perhaps even some teeth. A wolffian cyst is also very unlikely because of the age of the patient. Parasitic cysts do occur rarely in this country. Daughter cysts are often present, and they frequently have a thick wall. About 20 percent of echinococcal cysts are found outside the liver or the lung, especially in the peritoneum, spleen, small bowel, and kidney [3]. There are a few case reports of their occurrence in the mesentery and omentum, although most of the patients had echinococcal cysts elsewhere. However, these cysts are very rare, and our patient’s presentation would be atypical, so I think we can eliminate them from consideration. Now, by elimination, we come to tumors. A large review of 44 cases of mesenteric tumors has been published [4]. Omental tumors have been reviewed by the same workers [5]. Among mesenchymal tumors found in the omentum or mesentery, at least 50 percent were malignant. This is not the case for mesenchymal tumors occurring elsewhere in the body, which are usually benign. Most of these malignancies were low-grade and metastasized late and very slowly. They were derived from any element of the mesentery. In the series of mesenteric tumors [4], nonmalignant tumors included fibromas (25 percent of the cases), myomas (15 percent), lipomatous lesions (15 percent), histiocytic tumors (15 percent), vascular tumors (10 percent), neurofibromas (5 percent), and “other” (15 percent). Unfortunately, these percentages do not help in the diagnosis of individual cases. In other words, although I think that this patient has a tumor, and there is a 50 percent chance that it is malignant, it could be anything on this list. I would like to discuss some of these categories a bit further. First, let us talk about “other.” Although I have not found a single report of melanoma in the mesentery without concomitant evidence of liver metastasis, it must be considered. A melanoma would not have been easily detected in this man, and this tumor is known to become cystic at times. Lipomatous tumors also need to be considered further. It is difficult to explain how an omental or mesenteric tumor could become cystic in the center and contain such a huge amount of fluid. It is interesting in this regard that lipomatous tumors in the mesentery are not
80
CPC--HUGE
like ordinary adipose tissue. Although they contain lipomatous remnants, they cannot maintain lipogenesis. Thus, these tumors contain no fat-filled cells. Other lipomatous tumors (which do maintain lipogenesis) occur in the sliding spaces between muscles in the leg and the shoulder, and they can also occur in the retroperitoneum or the perirenal areas of the mesentery, in addition to the common sites in the gastrointestinal tract. They can grow to enormous size, and a number of articles have cited an anecdotal case of a lipomatous sarcoma of the mesentery that weighed 275 pounds. That, of course, is a bizarre case, but the point is that lipomas can be very big. These tumors have been reviewed earlier [6]. Now a word or two about omental tumors before I come back to mesenteric tumors. Omental tumors are not very different from mesenteric tumors except that the cell types are more restricted. The intriguing thing to me about omental tumors is that about 60 percent are myomas of one sort or another. It is possible that this patients tumor is omental since it is so big that an omental or mesenteric localization cannot be determined. The only certainty is that it is not a pancreatic tumor. This is the point I was at until this morning. I was going to predict a liposarcoma because liposarcomas occur largely in elderly people and can be cystic. Hamartomas and hemangiosarcomas can also be cystic, but computed tomography demonstrated no findings suggestive of these tumors. Then, in the last hour, there was a discussion of cystic lesions of the liver at our gastrointestinal division’s grand rounds. I was reminded of the fact that there are three tumors that characteristically form cystic spaces in the liver: melanoma, cancer of the colon (easily eliminated here on the basis of the barium enema), and leiomyosarcoma. This was a relevant point because there is not much difference in the etiology of cystic tumors in one organ versus another. Then I remembered that our division recently treated a patient with multiple cystic lesions in the liver that were thought to be multiple hepatic abscesses. He was given antibiotics, and the lesions transiently improved. He then worsened clinically, and repeated computed tomographic scanning again showed multiple cystic lesions in the liver. When his gastrointestinal tract was examined, a lesion in the colon was found that turned out to be a leiomyosarcoma. The lesions in the liver were, in fact, metastases (Figure 6). I do not know if the mesentery can behave like the liver, since I could not find a single case of cystic lesions in the mesentery. However, we do know that cystic lesions are a pattern seen in leiomyosarcoma, when there is central necrosis. If the patient had a solid cystic tumor of some sort and then bled into the tumor (perhaps as the result of a sneeze), the tumor could enlarge enormously, and we could have a presentation like that in our patient. I will conclude by suggesting that we are dealing with a lesion of either the omentum or the transverse mesocolon, that
ABDOMINAL
MASS
Figure 6. Computed tomographic scan of another patient showing cystic lesions in liver ultimately found to be metastatic leiomyosarcoma.
this is a mesenchymal tumor of some sort, and, on the basis of this morning’s gastrointestinal rounds, that this might be a leiomyosarcoma. Before we see the pathologic sections, Dr. Halverson, who performed the surgery, will comment. Dr. John Halverson: At surgery, we found a gigantic mass that pushed the transverse colon inferiorly and the stomach anteriorly. It filled the entire incision, and it extended upward (by palpation) under the stomach. It was adherent to the back of the stomach and, in fact, extended to the spleen, Confronted with the difficulty of removing this large mass, we aspirated 2 liters of sanguinous fluid from the cyst, which caused it to collapse. This allowed us to dissect around the periphery in order to determine resectability. Not long after we aspirated the fluid, we saw that there was also fresh blood coming from the cyst, making it quite obvious that the mass had to be removed. PATHOLOGIC DISCUSSION Dr. Frank Pikul: The gross tumor specimen excised at surgery measured 26.0 by 2 1 .O by 8.5 cm and weighed 2,450 g. On cut section, large areas of necrotic debris and hemorrhage were present. Histologically, the tumor was characterized by bundles and fascicles of spindleshaped tumor cells with a slightly eosinophilic, indistinct cytoplasm (Figure 7). The nuclei were elongated and cigar-shaped, and focally many of the cells contained small, cytoplasmic vacuoles indenting the nucleus. Other portions of the tumor had a palisading appearance, with the nuclei forming bands or ribbons. These histologic features indicate a smooth muscle tumor. However, in order to define whether the tumor is
March
1986
The American
Journal
of Medicine
Volume
80
481
CPC-HUGE
ABDOMINAL
MASS
Figure 7. Cellular tumor consisting of fascicles of spindle-shaped cells (hematoxylin and eosin stain; original magnification X 200, reduced by 30 percent).
Figure 8. Spindle-shaped cells with elongated nuclei and numerous mitotic figures (hematoxylin and eosin stain; oris inal magnification X 400, reduced by 30 percent).
malignant, we need to count mitotic figures. Throughout the tumor there were 12 to 14 mitotic figures per 10 highpower fields (Figure 8). Periodic acid-Schiff stains for glycogen gave strongly positive results. This, then, represents a leiomyosarcoma. The tumor arose’ in the transverse mesocolon, was adherent to the transverse colon, and metastasized to a portion of the descending colon (1.5 by 1.3 by 0.5 cm serosal nodule). The metastasis invaded the bowel wall muscularis only. Histologically, it was the same as the primary tumor. At surgery, the spleen was also removed. On gross examination, it
weighed 30 g and was unremarkable; histologically, it showed open sinuses with fibrotically thickened cords. No tumor was seen. Leiomyosarcomas account for approximately 5 to 7 percent of all soft tissue sarcomas. Approximately 50 to 60 percent are located in the retroperitoneum. The prognosis is usually not good. They do have a tendency to metastasize, primarily to the liver and lung; however, the metastases may not appear for a long time, even for 20 to 30 years [4,7-IO]. Final pathologic diagnosis: Leiomyosarcoma.
REFERENCES 1.
2.
3. 4. 5. 6.
482
Campagno J, Oertel JE: Microcystic adenomas of the pancreas (glycogen-rich cystadenomas): a clinicopathologic study of 34 cases. Am J Clin Pathol 1978; 69: 289-298. ltai Y, Moss AH, Ohtoma K: Computed tomography of cystadenoma and cystadenocarcinoma of the pancreas. Radiology 1982; 145: 419-425. Amir-Jahed AK, Fardin R, Farzad A, Bakshandcha K: Clinical echinococcosis. Ann Surg 1975; 182: 541-546. Yannopoulos K, Stout AP: Primary solid tumors of the mesentery. Cancer 1963; 16: 914-927. Stout AP, Hendry J, Purdie F: Primary solid tumors of the great omentum. Cancer 1963; 16: 231-243. Enzimger A, Winslow DJ: Liposarcoma, a study of 103
March
1986
The American
Journal
of Medicine
Volume
7.
8. 9.
0.
80
cases. Virchows Arch Pathol Anat Physiol Klin Med 1962; 335: 367. Golden T, Stout AP: Smooth muscle tumors of the gastrointestinal tract and retroperitoneal tissues. Surg Gynecol Obstet 1941; 73: 784-810. Kay S, McNeil1 DD: Leiomyosarcoma of the retroperitoneum. Surg Gynecol Obstet 1989; 129: 285-288. Ranched M, Kempson RL: Smooth muscle tumors of the gastrointestinal tract and retroperitoneum. A pathologic analysis of 100 cases. Cancer 1977; 39: 255-262. Russell WO, Cohen J, Enzinger F, et al: A clinical and pathological staging system for soft tissue sarcomas. Cancer 1977; 40: 1562-1570.
Huge Abdominal Mass in a 69-Year-Old Man
Stenographic reports of weekly clinicopathologic conferences held in Barnes and Wohl Hospitals are published in each issue of the Journal. Members of the Departments of Internal Medicine, Radiology, and Pathology of the Washington University School of Medicine participate jointly in these conferences. Kenneth M. Ludmerer, M.D., and John M. Kissane, M.D., are the editors of this feature. A 69-year-old black man was admitted to Barnes Hospital on August 8, 1984, for evaluation of abdominal distention. The patient had been well until IO days prior to admission, when mild dull pain in the left lower quadrant developed after sneezing. The pain persisted, and the next morning, he noted abdominal distention and generalized “soreness.” His stools became more frequent, of smaller caliber, and quite dark. The abdominal pain was intermittent, but the distention did not change. His appetite had been poor for two weeks. There was no fever, chills, nausea, vomiting, chest pain, jaundice, frank melena, or bright red rectal blood, Physical examination on admission revealed a temperature of 36.5OC, a blood pressure of 126/88 mm Hg (lying and standing), a pulse rate of 78 per minute (lying) and 96 per minute (standing), and a respiratory rate of 22 per minute. A 1 cm mobile, firm, right supraclavicular mass was present. The abdomen was protuberant, tense, and nontender with central dullness and surrounding tympany. A fluid wave, a left lower quadrant pulsatile sensation, and a reducible right inguinal hernia were noted. Rectal examination demonstrated increased tone, moderate tenderness, and a nodular prostate. The stool contained no occult blood. Results of laboratory evaluation included normal electrolyte and chemical values, except for a lactic dehydrogenase of 320 IL-f/liter. The hemoglobin level was 12.9 g/dl, the hematocrit 39.1 percent, and the white blood cell count 7,l 00/mm3. Results of urinalysis were unremarkable, and the serum amylase was 57 Ill/liter. Computed tomographic scanning of the abdomen demonstrated a large retroperitoneal cystic mass that was thought to be a pancreatic pseudocyst. Aspiration of the mass produced 2 liters of dark fluid, which contained a lactic dehydrogenase level of 3,980 It-f/liter, protein of 3.5 g/dl, amylase of 39 Ii-r/liter, total cell count of 123,220/mm3, and white blood ceil count of 1 ,321/mm3 (35 percent neutrophils). Cytologic examination of the fluid showed no abnormalities. Barium enema demonstrated downward displacement of the transverse colon by a large abdominal mass, with compression of the descending and sigmoid colon; there was no intrinsic
March
1966
The American
Journal
of Medicine
Volume
60
477
CPC-HUGE
ABDOMINAL
fgure 1. Anatomy text for discussion.
MASS
of certain abdominal
structures.
verse mesocolon to the retroperitoneum. The small bowel is connected by its mesentery to the retroperitoneum. The transverse mesocolon originates on top of the pancreas and just above the duodenum. From the radiographic evidence, either the lesion is in the omentum or transverse mesocolon, or else it is in the lesser sac between these two structures. The differential diagnosis will depend upon the location of the lesion. If the mass is in the lesser sac, we have to include processes that might involve the pancreas and duodenum. If it is in the transverse mesocolon or the omentum, it most likely represents some kind of cystic or tumorous lesion. An im~portant question is whether we can eliminate the pancreas from consideration. At this point I would like Dr. Levitt to review the radiographic findings. Dr. Robert Levitt: Computed tomographic examination of the abdomen was obtained upon admission. Scanning after intravenous injection of contrast material revealed a very large nonhomogeneous mass. This mass had a lowdensity central region surrounded by a thick wall. In the upper abdomen, the mass was situated between an anteriorly displaced stomach and a normal-sized pancreas (Figure 2). In the lower abdomen, the mass was situated anterior to the transverse colon (Figure 3). Serial computed tomography showed that the mass could have arisen from the retroperitoneum, greater omentum, or transverse mesocolon. Barium enema showed the mass displacing the transverse colon inferiorly, but the colon was intrinsically normal (Figure 4). On the second admission, 3 liters of serosanguinous fluid was drained from the mass percutaneously, and iodinated contrast material was instilled into the mass. A supine abdominal film showed that the instilled contrast material surrounded the transverse colon (Figure 5). On fluoroscopy, the contrast material appeared to be within the transverse mesocolon. Dr. Alpers: I spoke with the physician who performed the barium enema, and he said that he was impressed by the pattern of the barium fanning out into the transverse mesocolon, but we not have any pictures to demonstrate that. It is likely that there was blood in the center of the mass, and, as demonstrated by computed tomography, the mass had a thick wall. In addition, the blood level of lactic dehydrogenase was roughly 300 Ill/liter, whereas the lactic dehydrogenase level in fluid from the mass was nearly 4,000 Ill/liter. These observations suggest the possibility of a tumor. Let me first go through some things that I think the lesion is not We will start with lesions that are located in the lesser sac. Keep in mind that if the lesion originated from the lesser sac, it would have to burrow through the transverse mesocolon in order to end up anterior to the colon, as seen radiographically. That possibility seems unlikely to me. Nonetheless, the four lesionsto be consid-
See
colonic abnormality. The patient was discharged with anticipation of future laparotomy. The patient’s symptoms persisted, and he was readmitted to Barnes Hospital on September 4, 1984. Findings on physical examination were unchanged. The albumin level was 3.3 g/dl, lactic dehydrogenase 295 Ill/liter, acid phosphatase 0.24 Ill/liter (normal, less than 0.7 IMiter), and carcinoembryonic antigen 2.7 ng/dl (normal, less than 2.5 ng/dl). Aspiration removed 3 liters of serosanguinous fluid from the mass. The fluid cell count and chemical values were similar to those of the previous drainage procedure. Contrast medium was injected into the cavity, demonstrating that it lay superior and anterior to the transverse colon and medial to the splenic flexure. The cavity conformed to the expected configuration of the transverse mesocolon. Upper gastrointestinal series with small bowel follow-through demonstrated a mass effect, with displacement of the stomach, duodenum, jejunum, and colon at the splenic flexure. A procedure was performed. CLINICAL DISCUSSION Dr. David Alpers: There are two important aspects to this case. First, as far as the care of this patient is concerned, an operative procedure was mandatory. It was necessary to remove the cystic mass to discover its identity and resolve the patient’s symptoms. Second, the precise anatomic location of the lesion was important, to allow an intelligent guess concerning its nature. Let us consider the localization of the lesion. The stomach is suspended from the underside of the liver, and the greater curvature is extended by the omentum to the colon (Figure 1). The colon is connected by the trans-
478
March
1986
The
American
Journal
of Medicine
Volume
80
CPC-HUGE
ABDOMINAL
MASS
Figure 2. Computed tomographic scan through upper abdomen shows nonhomogeneous mass situated between air-filled stomach (s) and pancreas (arrows).
Figure 3. Computed tomographic scan through lower ab domen shows the mass is situated anterior to the transverse colon (arrows). The mass has a low-density central region surrounded by a thick wali.
Figure 4. Barium enema normal transverse colon.
Figure 5. Supine abdominal film after iodinated material was instilled into mass shows contrast collecting around transverse colon.
film showing
mass effect upon
March
1988
The American
Journal
of Medicine
Volume
contrast material
80
479
CPC-HUGE
ABDOMINAL
MASS
ered are a pancreatic pseudocyst, abscess, cystadenoma, and cystadenocarcinoma. We can quickly dismiss the pseudocyst and abscess, because the amylase level was not increased in the aspirated fluid. Moreover, there was very little inflammatory response in the cyst. There were 1,300 white blood cells, only 35 percent of which were polymorphonuclear leukocytes, and there was no fever or report of constitutional symptoms. All the findings expected with a pancreatic abscess were absent. When you add to this the fact that a location anterior to the colon is highly unusual for a pancreatic pseudocyst or abscess, we can eliminate these diagnoses. I would like to point out that this man was not an alcoholic and did not have biliary tract disease. In every series, a significant percentage (up to 50 percent, but usually around 10 or 20 percent) of cases of chronic pancreatitis are idiopathic. The absence of either alcoholism or cholecystitis does not, in any way, eliminate chronic pancreatitis. Still, these facts lessen the possibility of pseudocyst. Now as far as cystadenoma and cystadenocarcinoma are concerned, the two of them together represent about 1 percent of all pancreatic tumors. That does not argue against them in the differential diagnosis of this case, since the lesion is so unusual. These tumors account for about 10 percent of all pancreatic cystic lesions, simple cysts accounting for the rest. They usually occur in middle-aged females; in one series, 82 percent of them were in females [I]. They typically present with pain, nausea and vomiting, and weight loss-symptoms this man had. Frequently, there is associated pancreatitis, which he did not have. Only 10 percent of these lesions calcify, so the absence of calcification in this case is not a strong point against the diagnosis. The main argument against this diagnosis is the computed tomographic evidence, since cystadenomas usually present with numerous tiny, glycogen-filled cysts [2]. The cysts occur mostly in the body and the tail and can be as large as 30 cm in diameter. In this patient, scanning showed no evidence of such cysts. The scanning results also were not typical of cystadenocarcinomas, which are multiloculated and have mutinous fluid in the center. Now I would like to discuss lesions of the mesocolon and the omentum. Different types of tumors affect these two regions; they both can be involved by the same type of cysts. The developmental difference between these two structures is that, during its embryologic stages, the mesentery has cells that can differentiate into any type of mesenchymal cell. Thus, the mesentery can contain fibrous tissue, smooth muscle elements, lipomatous elements, and blood vessels, whereas the omentum is much more restricted and does not give rise to so many different varieties of tumors. Let us start with a discussion of cysts. I would preface these remarks by saying I think the lesion is unlikely to be
480
March
1988
The American
Journal
of Medicine
Volume
a cyst because the wall was so thick and because most cysts present in the fourth or fifth decades rather than at this patient’s age. Cysts are usually benign. They can enlarge very rapidly because of bleeding or torsion. Types of cysts include wolffian remnants of the genitourinary system, lymphatic cysts, mesocolic cysts (which are basically simple cysts of the mesocolon), dermoid cysts, and parasitic cysts. Lymphatic and mesocolic cysts are lined by simple epithelium and thus are very unlikely, unless this was a cyst in which inflammation or bleeding had gone on for such a long time that a thick wall was produced. With a dermoid cyst, some kind of irregularity of contour would be expected and perhaps even some teeth. A wolffian cyst is also very unlikely because of the age of the patient. Parasitic cysts do occur rarely in this country. Daughter cysts are often present, and they frequently have a thick wall. About 20 percent of echinococcal cysts are found outside the liver or the lung, especially in the peritoneum, spleen, small bowel, and kidney [3]. There are a few case reports of their occurrence in the mesentery and omentum, although most of the patients had echinococcal cysts elsewhere. However, these cysts are very rare, and our patient’s presentation would be atypical, so I think we can eliminate them from consideration. Now, by elimination, we come to tumors. A large review of 44 cases of mesenteric tumors has been published [4]. Omental tumors have been reviewed by the same workers [5]. Among mesenchymal tumors found in the omentum or mesentery, at least 50 percent were malignant. This is not the case for mesenchymal tumors occurring elsewhere in the body, which are usually benign. Most of these malignancies were low-grade and metastasized late and very slowly. They were derived from any element of the mesentery. In the series of mesenteric tumors [4], nonmalignant tumors included fibromas (25 percent of the cases), myomas (15 percent), lipomatous lesions (15 percent), histiocytic tumors (15 percent), vascular tumors (10 percent), neurofibromas (5 percent), and “other” (15 percent). Unfortunately, these percentages do not help in the diagnosis of individual cases. In other words, although I think that this patient has a tumor, and there is a 50 percent chance that it is malignant, it could be anything on this list. I would like to discuss some of these categories a bit further. First, let us talk about “other.” Although I have not found a single report of melanoma in the mesentery without concomitant evidence of liver metastasis, it must be considered. A melanoma would not have been easily detected in this man, and this tumor is known to become cystic at times. Lipomatous tumors also need to be considered further. It is difficult to explain how an omental or mesenteric tumor could become cystic in the center and contain such a huge amount of fluid. It is interesting in this regard that lipomatous tumors in the mesentery are not
80
CPC--HUGE
like ordinary adipose tissue. Although they contain lipomatous remnants, they cannot maintain lipogenesis. Thus, these tumors contain no fat-filled cells. Other lipomatous tumors (which do maintain lipogenesis) occur in the sliding spaces between muscles in the leg and the shoulder, and they can also occur in the retroperitoneum or the perirenal areas of the mesentery, in addition to the common sites in the gastrointestinal tract. They can grow to enormous size, and a number of articles have cited an anecdotal case of a lipomatous sarcoma of the mesentery that weighed 275 pounds. That, of course, is a bizarre case, but the point is that lipomas can be very big. These tumors have been reviewed earlier [6]. Now a word or two about omental tumors before I come back to mesenteric tumors. Omental tumors are not very different from mesenteric tumors except that the cell types are more restricted. The intriguing thing to me about omental tumors is that about 60 percent are myomas of one sort or another. It is possible that this patients tumor is omental since it is so big that an omental or mesenteric localization cannot be determined. The only certainty is that it is not a pancreatic tumor. This is the point I was at until this morning. I was going to predict a liposarcoma because liposarcomas occur largely in elderly people and can be cystic. Hamartomas and hemangiosarcomas can also be cystic, but computed tomography demonstrated no findings suggestive of these tumors. Then, in the last hour, there was a discussion of cystic lesions of the liver at our gastrointestinal division’s grand rounds. I was reminded of the fact that there are three tumors that characteristically form cystic spaces in the liver: melanoma, cancer of the colon (easily eliminated here on the basis of the barium enema), and leiomyosarcoma. This was a relevant point because there is not much difference in the etiology of cystic tumors in one organ versus another. Then I remembered that our division recently treated a patient with multiple cystic lesions in the liver that were thought to be multiple hepatic abscesses. He was given antibiotics, and the lesions transiently improved. He then worsened clinically, and repeated computed tomographic scanning again showed multiple cystic lesions in the liver. When his gastrointestinal tract was examined, a lesion in the colon was found that turned out to be a leiomyosarcoma. The lesions in the liver were, in fact, metastases (Figure 6). I do not know if the mesentery can behave like the liver, since I could not find a single case of cystic lesions in the mesentery. However, we do know that cystic lesions are a pattern seen in leiomyosarcoma, when there is central necrosis. If the patient had a solid cystic tumor of some sort and then bled into the tumor (perhaps as the result of a sneeze), the tumor could enlarge enormously, and we could have a presentation like that in our patient. I will conclude by suggesting that we are dealing with a lesion of either the omentum or the transverse mesocolon, that
ABDOMINAL
MASS
Figure 6. Computed tomographic scan of another patient showing cystic lesions in liver ultimately found to be metastatic leiomyosarcoma.
this is a mesenchymal tumor of some sort, and, on the basis of this morning’s gastrointestinal rounds, that this might be a leiomyosarcoma. Before we see the pathologic sections, Dr. Halverson, who performed the surgery, will comment. Dr. John Halverson: At surgery, we found a gigantic mass that pushed the transverse colon inferiorly and the stomach anteriorly. It filled the entire incision, and it extended upward (by palpation) under the stomach. It was adherent to the back of the stomach and, in fact, extended to the spleen, Confronted with the difficulty of removing this large mass, we aspirated 2 liters of sanguinous fluid from the cyst, which caused it to collapse. This allowed us to dissect around the periphery in order to determine resectability. Not long after we aspirated the fluid, we saw that there was also fresh blood coming from the cyst, making it quite obvious that the mass had to be removed. PATHOLOGIC DISCUSSION Dr. Frank Pikul: The gross tumor specimen excised at surgery measured 26.0 by 2 1 .O by 8.5 cm and weighed 2,450 g. On cut section, large areas of necrotic debris and hemorrhage were present. Histologically, the tumor was characterized by bundles and fascicles of spindleshaped tumor cells with a slightly eosinophilic, indistinct cytoplasm (Figure 7). The nuclei were elongated and cigar-shaped, and focally many of the cells contained small, cytoplasmic vacuoles indenting the nucleus. Other portions of the tumor had a palisading appearance, with the nuclei forming bands or ribbons. These histologic features indicate a smooth muscle tumor. However, in order to define whether the tumor is
March
1986
The American
Journal
of Medicine
Volume
80
481
CPC-HUGE
ABDOMINAL
MASS
Figure 7. Cellular tumor consisting of fascicles of spindle-shaped cells (hematoxylin and eosin stain; original magnification X 200, reduced by 30 percent).
Figure 8. Spindle-shaped cells with elongated nuclei and numerous mitotic figures (hematoxylin and eosin stain; oris inal magnification X 400, reduced by 30 percent).
malignant, we need to count mitotic figures. Throughout the tumor there were 12 to 14 mitotic figures per 10 highpower fields (Figure 8). Periodic acid-Schiff stains for glycogen gave strongly positive results. This, then, represents a leiomyosarcoma. The tumor arose’ in the transverse mesocolon, was adherent to the transverse colon, and metastasized to a portion of the descending colon (1.5 by 1.3 by 0.5 cm serosal nodule). The metastasis invaded the bowel wall muscularis only. Histologically, it was the same as the primary tumor. At surgery, the spleen was also removed. On gross examination, it
weighed 30 g and was unremarkable; histologically, it showed open sinuses with fibrotically thickened cords. No tumor was seen. Leiomyosarcomas account for approximately 5 to 7 percent of all soft tissue sarcomas. Approximately 50 to 60 percent are located in the retroperitoneum. The prognosis is usually not good. They do have a tendency to metastasize, primarily to the liver and lung; however, the metastases may not appear for a long time, even for 20 to 30 years [4,7-IO]. Final pathologic diagnosis: Leiomyosarcoma.
REFERENCES 1.
2.
3. 4. 5. 6.
482
Campagno J, Oertel JE: Microcystic adenomas of the pancreas (glycogen-rich cystadenomas): a clinicopathologic study of 34 cases. Am J Clin Pathol 1978; 69: 289-298. ltai Y, Moss AH, Ohtoma K: Computed tomography of cystadenoma and cystadenocarcinoma of the pancreas. Radiology 1982; 145: 419-425. Amir-Jahed AK, Fardin R, Farzad A, Bakshandcha K: Clinical echinococcosis. Ann Surg 1975; 182: 541-546. Yannopoulos K, Stout AP: Primary solid tumors of the mesentery. Cancer 1963; 16: 914-927. Stout AP, Hendry J, Purdie F: Primary solid tumors of the great omentum. Cancer 1963; 16: 231-243. Enzimger A, Winslow DJ: Liposarcoma, a study of 103
March
1986
The American
Journal
of Medicine
Volume
7.
8. 9.
0.
80
cases. Virchows Arch Pathol Anat Physiol Klin Med 1962; 335: 367. Golden T, Stout AP: Smooth muscle tumors of the gastrointestinal tract and retroperitoneal tissues. Surg Gynecol Obstet 1941; 73: 784-810. Kay S, McNeil1 DD: Leiomyosarcoma of the retroperitoneum. Surg Gynecol Obstet 1989; 129: 285-288. Ranched M, Kempson RL: Smooth muscle tumors of the gastrointestinal tract and retroperitoneum. A pathologic analysis of 100 cases. Cancer 1977; 39: 255-262. Russell WO, Cohen J, Enzinger F, et al: A clinical and pathological staging system for soft tissue sarcomas. Cancer 1977; 40: 1562-1570.