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Ectopic Splenic Tissue Simulating a Renal Mass
00226347/95/1535-1610$03.00/0
Vol. 153, 1610-1611,May 1995 Printed in U.S.A.
THE JOURNAL OF UROUxiY
Copyright 0 1995 by AMERICAN U R O ~ I CASSOCIATION, AL bc.
Case Reports ECTOPIC SPLENIC TISSUE SIMULATING A RENAL MASS DOV LASK, JOSEPH ABARBANEL, YADWIGA RECHNIC AND ELIAHU MUKAMEL From the Departments of Urology and Nuclear Medicine, "Golda"Medical Center, Hashuron Hospital, Petah Tiqua, Israel
ABSTRACT
A 64-year-old patient who underwent splenectomy presented clinically with ectopic splenic tissue simulating a solid renal mass. The splenic origin of the mass was assessed by radionuclide spleen scan. Nephrectomy was avoided. KEYWORDS:kidney neoplasms, spleen, choristoma The term ectopic splenic tissue refers to either splenosis or an accessory spleen. Splenosis,' or regenerated ectopic autotransplanted splenic tissue, may appear intraperitoneally or extraperitoneally following splenectomy performed for rupture.2 An accessory spleen, which is normal splenic tissue, may enlarge following splenectomy to the size of a normal The nature of the ecspleen and can function adeq~ately.~ topic splenic tissue is confirmed by '9"technetium (""Tc)sulfur colloid scanning' or by 99mTc-labeledheat denatured autologous red blood cells in the case of a smaller splenic mass.6 Ectopic splenic tissue is usually asymptomatic and is rarely diagnosed preoperatively. In a recent report left nephrectomy was done for a renal mass in direct continuity with the kidney.6 Histological examination revealed the splenic origin of the mass. The importance of performing a preoperative radionuclide spleen scan to verify the splenic origin of an abdominal mass in patients following splenectomy is illustrated by our case.
ileus caused by intestinal adhesions. During surgery the spleen was injured and removed. Physical examination showed multiple abdominal scars, and on rectal palpation the prostate was mildly enlarged and regular. Abdominal ultrasound revealed a 5 cm. solid echogenic mass emerging from the upper pole of the left kidney (fig. 1).Computerized tomography (CT) demonstrated the same solid mass with a highly vascular capsule (fig. 2). Because of the history of splenectomy, a splenic origin of the mass was suspected and a radionuclide splenic scan with ""Tc-sulfur colloid was performed. An area of increased uptake in the left upper abdominal quadrant was found, confirming the splenic nature of the mass noted on ultrasound and CT (fig. 3).A search was made for small ectopic splenic tissue using 99mTc-labeled heat denatured autologous red blood cells and no additional splenic masses were found. The hematological and immunological findings suggesting adequate splenic activity included absence of Howell-Jolly bodies, 10%pitted erythrocytes, and normal levels of IgA, IgG and IgM.
CASE REPORT
DISCUSSION
A 64-year-old man was evaluated for prostatism. The patient underwent 4 operations 40 years ago for obstructive
Perla suggested a specific pattern in the regeneration of splenic transplants.7 During the first 24 hours after transplantation the implant degenerates except for some reticulum cells from the peripheral area, which survive. These cells
Accepted for publication September 23, 1994.
hc. 1. Transverse sonogram of left kidney demonstrates solid mass arising from lateral upper margin.
FIG. 2. CT after administration of intravenous contrast material shows same mass (arrow) emerging from renal parenchyma. 1610
ECTOPIC SPLENIC TISSUE SIMULATING RENAL MASS
1611
99”Tc-sulfur colloid scanning4 or by 99”’Tc-labeled heat denatured autologous red blood cells.5 The latter test enables detection of ectopic splenic foci as small as 1 x 1 cm. in diameter, a size easily missed by the less sensitive sulfur colloid scan. The spleen normally traps only 10% of the injected sulfur colloid, while it takes up to 90% of the heat denatured labeled red blood cells. Moreover, this technique provides an objective measurement of the ectopic splenic tissue trapping function. Thus, splenic scintigraphy using 99”Tc-labeled heat denatured red blood cells is a highly specific and sensitive method of morphological localization and functional evaluation of ectopic splenic tissue.’* Ectopic splenic tissue is usually asymptomatic and is rarely diagnosed preoperatively. In a recent report left nephrectomy was performed for a renal mass that on histological examination proved to be ectopic splenic tissue in direct continuity with the kidney.6 No radionuclide studies were done preoperatively. Occasionally, symptoms related to the presence of intraperitoneal ectopic splenic tissue may occur. Abdominal pain is caused by adhesions or intermittent torsion of a long vascular pedicle. Intraperitoneal hemorrhage may result from minor trauma to ectopic splenic tissue. Thus, the incidental finding of an asymptomatic abdominal mass in a patient who underwent splenectomy may suggest the existence of ectopic splenic tissue. Radionuclide isotope study is F , ~ 3, , hkrior view of 9 9 ” ~ ~ - ~ dcolloid f u r scan demonstrates focal area of splenic activity in left upper quadrant. L, liver. s m . , recommended in these patients to prevent unnecessary invasplenic mass. B, bladder. sive radiological examinations or surgical intervention. proliferate during the following 3 days, accompanied by migration into the necrotic center of the implant. Regeneration is complete at 12 to 21 days. This theory postulates that the reticular cells are the precursors of structural elements by retaining their potential for differentiation. Buchbinder and Lipkoff first used the term splenosis, describing autotransplantation of splenic fragments aRer splenic trauma.’ A recent report suggested that splenosis occurs in up to 67% of the patients following splenic rupture.s Splenosis should be differentiated from an ectopic accessory spleen, which also is common, being found in up to 44% of all autopsy cases.6 Splenosis and an accessory spleen are differentiated by several criteria. The nodules of splenosis are numerous, while those of an accessory spleen are few (usually less than 6).Splenosis may occur throughout the peritoneal or extraperitoneal regions, while accessory spleens are found along the spleno-pancreatic ligament. Accessory spleens have a normal histological appearance, while the nodules of splenosis have no particular shape, hilum or capsule, and consist of poorly defined follicles and fewer germinal cells.9 Splenic nodules derive their blood supply from arteries that penetrate the capsule from the surrounding tissue, while the accessory spleen is always supplied by a branch of the splenic artery.10 Splenic implants, as well as accessory spleens, may retain functional ability, such as ingestion of red blood cells and uptake of 99”Tc-sulfur colloid. The absence of Howell-Jolly bodies, siderocytes and other post-splenectomy cellular abnormalities on peripheral blood smear in a patient who underwent splenectomy is evidence of functioning splenic tissue.11 In some hematological diseases splenectomy is indicated as treatment. Failure of the procedure can be attributed to regained activity of an unidentified ectopic spleen preoperatively.12 Infection is rare in posttrauma splenectomy patients. The ectopic splenic tissue regains its primary lymphoid function and is important in the protection against i n f e ~ t i 0 n . l ~ The nature of the ectopic splenic tissue is assessed by
REFERENCES
1. Buchbinder, J. H. and Lipkoff, C. J.: Splenosis: multiple peritoneal splenic implants following abdominal surgery. Surgery,6 927,1939. 2. Fleming, C. R., Dickson, E. R. and Harrison, E. G., Jr.: Splenosis: autotransplantationof splenic tissue. Amer. J. Med., 61: 414, 1976. 3. Rao, K. G. and Fitzer, P. M.: Left suprarenal mass following splenectomy: case reports. J. Urol., 1 3 2 323, 1984. 4. Fitzer, P. M.: Preoperative diagnosis of splenosis by 99mTcsulfur colloid scanning. Clin. Nucl. Med., 2: 348, 1977. 5. Atkins, H. L., Goldman, A. G., Fairchild,R. G., Oster, Z. H., Som, P., Richards, P., Meinken, G. E. and Strivastava,S. C.: Splenic sequestration of 99mTc labeled, heat treated red blood cells. Radiology, 136: 501, 1980. 6. Bock, D. B., King, B. F., Hezmall, H. P. and Osterling, J. E.: Splenosis presenting as a left renal mass indistinguishable from renal cell carcinoma. J. Urol., 146. 152,1991. 7. Perla, D.: The regeneration of autoplastic splenic transplants. Amer. J. Path., 1 2 665,1936. 8. Turk, C. D.,Lipson, S. B. and Brandt, T. D.: Splenosis mimicking a renal mass. Urology, 31: 248, 1988. 9. Widmann, W.D. and Laubscher, F. A.: Splenosis. A disease or a beneficial condition? Arch. Surg., 1 0 2 152,1971. 10. Cohen, E. A.: Splenosis: review and report of subcutaneous splenic implant. Arch. Surg., 69 777, 1954. 11. Mackie, W. J. and Miller, D. F.: Splenosis. A case report and some considerations on the function of splenotic tissue. Brit. J. Surg., 60:56, 1973. 12. Pearson, H.A,, Johnston, D., Smith, K. A. and Touloukian, R. J.: The born-again spleen. Return of splenic function after splenectomy for trauma. New Engl. J. Med., 298: 1389, 1978. 13. Singer, T. D.: Post splenectomy sepsis. In: Perspectives in Pediatric Pathology. E&kd by H. S. Rosenberg and R. P. Boland. Chicago: Year Book Medical Publishers, vol. 1, pp. 285-311, 1973. 14. Zwas, S. T.,Samra, D., Samra, Y. and Sibber, G. R.: Scintigraphic assessment of ectopic splenic tissue localization and function following splenectomy for trauma. Eur. J. Nucl. Med., 1 2 125,1986.
Vol. 153, 1610-1611,May 1995 Printed in U.S.A.
THE JOURNAL OF UROUxiY
Copyright 0 1995 by AMERICAN U R O ~ I CASSOCIATION, AL bc.
Case Reports ECTOPIC SPLENIC TISSUE SIMULATING A RENAL MASS DOV LASK, JOSEPH ABARBANEL, YADWIGA RECHNIC AND ELIAHU MUKAMEL From the Departments of Urology and Nuclear Medicine, "Golda"Medical Center, Hashuron Hospital, Petah Tiqua, Israel
ABSTRACT
A 64-year-old patient who underwent splenectomy presented clinically with ectopic splenic tissue simulating a solid renal mass. The splenic origin of the mass was assessed by radionuclide spleen scan. Nephrectomy was avoided. KEYWORDS:kidney neoplasms, spleen, choristoma The term ectopic splenic tissue refers to either splenosis or an accessory spleen. Splenosis,' or regenerated ectopic autotransplanted splenic tissue, may appear intraperitoneally or extraperitoneally following splenectomy performed for rupture.2 An accessory spleen, which is normal splenic tissue, may enlarge following splenectomy to the size of a normal The nature of the ecspleen and can function adeq~ately.~ topic splenic tissue is confirmed by '9"technetium (""Tc)sulfur colloid scanning' or by 99mTc-labeledheat denatured autologous red blood cells in the case of a smaller splenic mass.6 Ectopic splenic tissue is usually asymptomatic and is rarely diagnosed preoperatively. In a recent report left nephrectomy was done for a renal mass in direct continuity with the kidney.6 Histological examination revealed the splenic origin of the mass. The importance of performing a preoperative radionuclide spleen scan to verify the splenic origin of an abdominal mass in patients following splenectomy is illustrated by our case.
ileus caused by intestinal adhesions. During surgery the spleen was injured and removed. Physical examination showed multiple abdominal scars, and on rectal palpation the prostate was mildly enlarged and regular. Abdominal ultrasound revealed a 5 cm. solid echogenic mass emerging from the upper pole of the left kidney (fig. 1).Computerized tomography (CT) demonstrated the same solid mass with a highly vascular capsule (fig. 2). Because of the history of splenectomy, a splenic origin of the mass was suspected and a radionuclide splenic scan with ""Tc-sulfur colloid was performed. An area of increased uptake in the left upper abdominal quadrant was found, confirming the splenic nature of the mass noted on ultrasound and CT (fig. 3).A search was made for small ectopic splenic tissue using 99mTc-labeled heat denatured autologous red blood cells and no additional splenic masses were found. The hematological and immunological findings suggesting adequate splenic activity included absence of Howell-Jolly bodies, 10%pitted erythrocytes, and normal levels of IgA, IgG and IgM.
CASE REPORT
DISCUSSION
A 64-year-old man was evaluated for prostatism. The patient underwent 4 operations 40 years ago for obstructive
Perla suggested a specific pattern in the regeneration of splenic transplants.7 During the first 24 hours after transplantation the implant degenerates except for some reticulum cells from the peripheral area, which survive. These cells
Accepted for publication September 23, 1994.
hc. 1. Transverse sonogram of left kidney demonstrates solid mass arising from lateral upper margin.
FIG. 2. CT after administration of intravenous contrast material shows same mass (arrow) emerging from renal parenchyma. 1610
ECTOPIC SPLENIC TISSUE SIMULATING RENAL MASS
1611
99”Tc-sulfur colloid scanning4 or by 99”’Tc-labeled heat denatured autologous red blood cells.5 The latter test enables detection of ectopic splenic foci as small as 1 x 1 cm. in diameter, a size easily missed by the less sensitive sulfur colloid scan. The spleen normally traps only 10% of the injected sulfur colloid, while it takes up to 90% of the heat denatured labeled red blood cells. Moreover, this technique provides an objective measurement of the ectopic splenic tissue trapping function. Thus, splenic scintigraphy using 99”Tc-labeled heat denatured red blood cells is a highly specific and sensitive method of morphological localization and functional evaluation of ectopic splenic tissue.’* Ectopic splenic tissue is usually asymptomatic and is rarely diagnosed preoperatively. In a recent report left nephrectomy was performed for a renal mass that on histological examination proved to be ectopic splenic tissue in direct continuity with the kidney.6 No radionuclide studies were done preoperatively. Occasionally, symptoms related to the presence of intraperitoneal ectopic splenic tissue may occur. Abdominal pain is caused by adhesions or intermittent torsion of a long vascular pedicle. Intraperitoneal hemorrhage may result from minor trauma to ectopic splenic tissue. Thus, the incidental finding of an asymptomatic abdominal mass in a patient who underwent splenectomy may suggest the existence of ectopic splenic tissue. Radionuclide isotope study is F , ~ 3, , hkrior view of 9 9 ” ~ ~ - ~ dcolloid f u r scan demonstrates focal area of splenic activity in left upper quadrant. L, liver. s m . , recommended in these patients to prevent unnecessary invasplenic mass. B, bladder. sive radiological examinations or surgical intervention. proliferate during the following 3 days, accompanied by migration into the necrotic center of the implant. Regeneration is complete at 12 to 21 days. This theory postulates that the reticular cells are the precursors of structural elements by retaining their potential for differentiation. Buchbinder and Lipkoff first used the term splenosis, describing autotransplantation of splenic fragments aRer splenic trauma.’ A recent report suggested that splenosis occurs in up to 67% of the patients following splenic rupture.s Splenosis should be differentiated from an ectopic accessory spleen, which also is common, being found in up to 44% of all autopsy cases.6 Splenosis and an accessory spleen are differentiated by several criteria. The nodules of splenosis are numerous, while those of an accessory spleen are few (usually less than 6).Splenosis may occur throughout the peritoneal or extraperitoneal regions, while accessory spleens are found along the spleno-pancreatic ligament. Accessory spleens have a normal histological appearance, while the nodules of splenosis have no particular shape, hilum or capsule, and consist of poorly defined follicles and fewer germinal cells.9 Splenic nodules derive their blood supply from arteries that penetrate the capsule from the surrounding tissue, while the accessory spleen is always supplied by a branch of the splenic artery.10 Splenic implants, as well as accessory spleens, may retain functional ability, such as ingestion of red blood cells and uptake of 99”Tc-sulfur colloid. The absence of Howell-Jolly bodies, siderocytes and other post-splenectomy cellular abnormalities on peripheral blood smear in a patient who underwent splenectomy is evidence of functioning splenic tissue.11 In some hematological diseases splenectomy is indicated as treatment. Failure of the procedure can be attributed to regained activity of an unidentified ectopic spleen preoperatively.12 Infection is rare in posttrauma splenectomy patients. The ectopic splenic tissue regains its primary lymphoid function and is important in the protection against i n f e ~ t i 0 n . l ~ The nature of the ectopic splenic tissue is assessed by
REFERENCES
1. Buchbinder, J. H. and Lipkoff, C. J.: Splenosis: multiple peritoneal splenic implants following abdominal surgery. Surgery,6 927,1939. 2. Fleming, C. R., Dickson, E. R. and Harrison, E. G., Jr.: Splenosis: autotransplantationof splenic tissue. Amer. J. Med., 61: 414, 1976. 3. Rao, K. G. and Fitzer, P. M.: Left suprarenal mass following splenectomy: case reports. J. Urol., 1 3 2 323, 1984. 4. Fitzer, P. M.: Preoperative diagnosis of splenosis by 99mTcsulfur colloid scanning. Clin. Nucl. Med., 2: 348, 1977. 5. Atkins, H. L., Goldman, A. G., Fairchild,R. G., Oster, Z. H., Som, P., Richards, P., Meinken, G. E. and Strivastava,S. C.: Splenic sequestration of 99mTc labeled, heat treated red blood cells. Radiology, 136: 501, 1980. 6. Bock, D. B., King, B. F., Hezmall, H. P. and Osterling, J. E.: Splenosis presenting as a left renal mass indistinguishable from renal cell carcinoma. J. Urol., 146. 152,1991. 7. Perla, D.: The regeneration of autoplastic splenic transplants. Amer. J. Path., 1 2 665,1936. 8. Turk, C. D.,Lipson, S. B. and Brandt, T. D.: Splenosis mimicking a renal mass. Urology, 31: 248, 1988. 9. Widmann, W.D. and Laubscher, F. A.: Splenosis. A disease or a beneficial condition? Arch. Surg., 1 0 2 152,1971. 10. Cohen, E. A.: Splenosis: review and report of subcutaneous splenic implant. Arch. Surg., 69 777, 1954. 11. Mackie, W. J. and Miller, D. F.: Splenosis. A case report and some considerations on the function of splenotic tissue. Brit. J. Surg., 60:56, 1973. 12. Pearson, H.A,, Johnston, D., Smith, K. A. and Touloukian, R. J.: The born-again spleen. Return of splenic function after splenectomy for trauma. New Engl. J. Med., 298: 1389, 1978. 13. Singer, T. D.: Post splenectomy sepsis. In: Perspectives in Pediatric Pathology. E&kd by H. S. Rosenberg and R. P. Boland. Chicago: Year Book Medical Publishers, vol. 1, pp. 285-311, 1973. 14. Zwas, S. T.,Samra, D., Samra, Y. and Sibber, G. R.: Scintigraphic assessment of ectopic splenic tissue localization and function following splenectomy for trauma. Eur. J. Nucl. Med., 1 2 125,1986.