- Email: [email protected]
Intra-Abdominal Splenosis Mimicking Metastatic Cancer
CASE REPORT
Intra-Abdominal Splenosis Mimicking Metastatic Cancer Nicholas J. Short, BA, Teresa G. Hayes, MD, PhD and Peeyush Bhargava, MD
Abstract: Splenosis, the heterotopic autotransplantion of splenic tissue, is a common benign condition among patients with a history of splenic trauma. Most cases of splenosis are intra-abdominal due to direct seeding of surrounding structures, although these ectopic rests may occur almost anywhere in the body, and its diffuse nature may raise the suspicion of metastatic cancer. Confirmation of splenic tissue can be made by technetium-99m (Tc-99m) sulfur colloid scintigraphy or with Tc-99m heat-damaged red blood cells; however, in some cases, biopsy may be required for definitive diagnosis. Here, the authors present a patient with a remote history of posttraumatic splenectomy who was discovered to have multiple intra-abdominal nodules by CT scan. A diagnosis of diffuse metastatic disease was initially considered before a diagnosis of intraabdominal splenosis was ultimately made with the aid of Tc-99m sulfur colloid single-positron emission computed tomography (SPECT) and computed tomography imaging. Key Indexing Terms: Splenosis; Abdominal mass; Tc-99m sulfur colloid scintigraphy; SPECT-CT. [Am J Med Sci 2011;341(3):246–249.]
A
CASE REPORT
60-year-old Caucasian man was referred to an oncology clinic for suspected diffuse metastatic disease of unknown primary. He had recently been treated for a urinary tract infection, and a computed tomography (CT) scan was ordered when the microscopic hematuria on repeat urinalysis had not resolved after a complete course of antibiotics. This CT scan revealed numerous soft tissue masses within the abdomen and pelvis. The patient’s medical history was remarkable only for a splenectomy at the age of 5 years following an injury sustained from a fall from a ladder. He had smoked 2 to 3 packs of cigarettes daily for the past 35 years, and his family history was significant for colon cancer in his paternal grandfather and breast cancer in his mother and maternal aunt. The patient had never had a colonoscopy. He had no complaints except for concern that he may have cancer. He denied fever, chills, night sweats, weight loss, headaches, chest pain, shortness of breath, abdominal pain, change in bowel habits or gross hematuria. Physical examination revealed no abnormalities, and laboratory tests (including complete blood count with differential, comprehensive metabolic panel, urinalysis with microscopy and prostate specific antigen) were unremarkable. The CT scan was repeated, and it confirmed the presence of multiple soft tissue nodules ranging from 1.7 to 4.6 cm diffusely scattered within the abdominopelvic cavity. No normal appearing spleen was identified; however, a splenule was noted in the left upper quadrant. Given the patient’s history of traumatic splenic rupture requiring splenectomy, a diagnosis of splenosis was suspected. Liver-spleen scintigraphy was performed by injection of 8.7
From the Departments of Hematology/Oncology (NJS, TGH) and Radiology (PB), Baylor College of Medicine, Houston, Texas. Submitted July 27, 2010; accepted in revised form October 13, 2010. Correspondence: Nicholas J. Short, BA, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 (E-mail: [email protected]).
246
mCi of technetium-99m (Tc-99m) sulfur colloid, and planar images of the abdomen and pelvis in anterior and posterior projections were obtained 15 minutes after injection (Figure 1). Single-positron emission computed tomography (SPECT)-CT fusion imaging was also performed (Figure 2), which showed uptake of all nodules visualized by previous CT scan except for 1 large 4.6 ⫻ 2.7 cm nodule abutting the left lobe of the liver. An ultrasound-guided biopsy of this nodule revealed red blood cells, lymphoid aggregates and sinusoids without any evidence of malignant cells, confirming ectopic splenic tissue. A final diagnosis of intra-abdominal splenosis was made, and the patient was much reassured to learn he did not have widespread cancer.
DISCUSSION Splenosis is the benign heterotopic autotransplanation of splenic tissue, most commonly following traumatic rupture of the spleen. It has been estimated that blunt trauma accounts for up to 93% of cases of splenosis1 and that some amount of splenosis results from up to two thirds of significant splenic injuries.2 The misplaced splenic tissue of splenosis should be differentiated from that of accessory spleens, which are common, benign, congenital ectopic rests of functional splenic tissue that have been estimated to occur in 10% to 30% of the population.2 Because these accessory spleens form during embryological development, they are generally found near the spleen proper. In contrast, the dominant mechanism proposed to explain splenosis is that following significant trauma to the spleen, pieces of splenic tissue are dislodged from the spleen proper and seed surrounding structures. Thus, most of these splenic implants occur in the abdominopelvic cavity, as illustrated in the patient presented here. Thoracic splenosis is the most frequently reported of the extra-abdominal cases of splenosis,3 and all reported cases of thoracic splenosis have been accompanied by a known history of diaphragmatic rupture.1 The unfamiliarity of this condition among many clinicians can lead to much confusion in the diagnosis of a patient presenting with imaging that shows multiple intra-abdominal soft tissue nodules, as occurred in the patient presented above. In such a case, a number of disease entities must be considered, including abdominal lymphoma, metastatic carcinoma, peritoneal carcinomatosis, generalized adenopathy, endometriosis and multiple hemangiomas.1 Additional disease processes must be considered in a patient with thoracic nodules. Although the radiographic appearance of these nodules is often nonspecific, a history of elective splenectomy or splenic injury requiring splenectomy should raise the possibility of splenosis, especially in cases without historical or physical evidence suggestive of other diagnoses. This point is especially salient in the patient presented above, as his good health, lack of constitutional symptoms and the eventual resolution of his microscopic hematuria—the only localizing sign or symptom by history and physical examination—significantly decreased the likelihood of serious pathology.
The American Journal of the Medical Sciences • Volume 341, Number 3, March 2011
Intra-Abdominal Splenosis
FIGURE 1. Tc-99m sulfur colloid scintigraphy images of the abdomen and pelvis in anterior (A) and posterior (B) projections. Increased uptake of radioactive tracer is noted in 3 discrete areas within the abdominal cavity.
Early consideration and diagnosis of this benign condition can prevent the use of invasive diagnostic procedures and reduce the patient’s anxiety about potential malignancy. In addition, identification of splenosis is especially important in patients with a known primary malignancy, as differentiation of this benign condition from diffuse metastatic disease will impact staging and treatment decisions in many cases. This has been illustrated in case reports of patients with bladder cancer,4 renal cell carcinoma5 and Hodgkin’s disease2 in which unnecessary chemotherapy has been avoided by distinguishing splenosis from metastatic disease or disease recurrence. Similar considerations must be made even in patients at high risk for malignancy but with a remote history of splenic trauma, as demonstrated in a case of intrahepatic splenosis mimicking hepatocellular carcinoma in a patient with hepatitis C and cirrhosis.6 When a diagnosis of splenosis is considered, nuclear scintigraphy is the preferred method of diagnosis. The first imaging modality described for this purpose was Tc-99m sulfur colloid scintigraphy; however, recent research has shown that a nuclear scan using Tc-99m heat-damaged red blood cells is more sensitive and specific for splenic tissue.1,7 The proposed basis for this increased accuracy is that splenic tissue takes up only 10% of sulfur colloid but 90% of damaged red blood cells.7 In addition, sulfur colloid scans have been shown to have especially poor visualization of splenic tissue when the liver and splenic tissue overlap, whereas heat-damaged red blood cells have less uptake by the liver and are thus less susceptible to signal interference by surrounding liver parenchyma.7–9 The poor visualization by sulfur colloid scintigraphy of splenic tissue abutting the liver is illustrated in the false-negative result obtained in the patient presented here. However, despite these advantages of nuclear imaging with heat-damaged red blood cells, sulfur colloid scintigraphy is more commonly used by radiologists for confirmation of ectopic splenic tissue due to familiarity with the procedure and its relative ease of use. In cases of suspected ectopic splenic tissue, the addition of SPECT-CT fusion imaging can allow for 3-dimensional anatomical correlation, which is especially beneficial when surgical intervention may be required or when localization is otherwise ambiguous with nuclear scintigraphy alone.10 Previous reports have shown SPECT-CT to be useful in the localization of splenic implants in cases of refractory immune thrombocytopenia purpura11 and in distinguishing accessory spleens from intra-abdominal malig© 2011 Lippincott Williams & Wilkins
nancy.12 However, although SPECT alone has long been used in the identification of splenosis, to our knowledge, there is only 1 previous report illustrating the utility of SPECT-CT fusion imaging in distinguishing splenosis from malignancy.13 Therefore, this report further elucidates the utility of SPECT-CT in diagnosing splenosis and differentiating it from other causes of intra-abdominal soft tissue masses. Finally, despite the available methods for radiological diagnosis, sometimes a biopsy of suspected ectopic splenic tissue is needed to give full diagnostic certainty of splenosis rather than some potentially serious pathology. Although biopsy of the spleen proper is often avoided due to a high risk of bleeding, biopsy of the splenic implants of splenosis is considered a safe procedure—as long as they can be easily accessed—and to our knowledge, there are no reports in the literature of significant complications from such a biopsy. Of note, the blood supply of the ectopic splenic tissue of splenosis differs significantly from that of the spleen proper, as these ectopic rests derive their blood supply from penetrating blood vessels of the surrounding tissue rather than from the splenic artery.1 The difference in blood supply of these 2 biopsy sites could possibly account for any differences in bleeding rates that may exist. In most cases, splenosis is a benign, asymptomatic condition that does not require treatment. In fact, the diagnosis is usually not considered until suspicious findings are seen on imaging performed in the course of evaluating unrelated symptoms. This is illustrated in the patient presented here who was diagnosed with splenosis after undergoing a CT scan for microscopic hematuria. It should be noted that despite the urinary tract infection and microscopic hematuria eventually leading to a diagnosis of splenosis, there is no evidence in this case that any causal relationship exists between these findings. Although, in theory, splenic implants located along the urinary tract could cause obstruction and thus predispose to urine stasis and bacterial growth, in this patient, no splenic nodules were identified near the urinary system by SPECT-CT imaging; however, a splenic implant somewhere along the urinary system large enough to cause obstruction but too small to be visualized by CT scan cannot be entirely excluded. The patient’s hematuria is also not easily explained by splenosis. As splenosis is not an invasive process, any splenic implants— even if located around the urinary tract—would not be expected to cause hematuria. Furthermore, the eventual resolution of the
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Short et al
FIGURE 2. SPECT-CT imaging of the abdomen (coronal, sagittal and axial sections) better characterizes the precise locations of the nodules seen by Tc-99m sulfur colloid scintigraphy. The nodule in the left upper quadrant (A) correlates with the splenule seen on a previous CT scan. The nodules in the anterior mesentery (B) and right lower quadrant (C) both correlate with intra-abdominal soft tissue nodules seen with previous CT imaging.
patient’s hematuria suggests that it was likely due to some transient process—most likely his preceding urinary tract infection—rather than splenosis. Although usually asymptomatic, in certain circumstances, surgical removal of ectopic splenic implants may be indicated. For example, there have been case reports of resolution of Felty’s syndrome,14 immune thrombocytopenia purpura15 and autoimmune hemolytic anemia16 after resection of the splenic implants of splenosis. Furthermore, although usually asymptomatic, there are reports of splenosis presenting with acute abdominal pain due to infarction,14 intestinal obstruction,17 gastrointestinal hemorrhage,18 ureteral compression19 or hemoptysis in the case of thoracic splenosis.20 In any
248
of these cases, removal of this misplaced splenic tissue may be necessary for symptomatic relief. REFERENCES 1. Fremont RD, Rice TW. Splenosis: a review. South Med J 2007;100: 589 –93. 2. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 29 –1995. A 65-year-old man with mediastinal Hodgkin’s disease and a pelvic mass. N Engl J Med 1995;333: 784 –91. 3. Sahin E, Karadayi S, Nadir A, et al. Thoracic splenosis accompanied by diaphragmatic hernia. Can J Surg 2009;52:E293– 4.
Volume 341, Number 3, March 2011
Intra-Abdominal Splenosis
4. Menth M, Herrmann K, Haug A, et al. Intra-hepatic splenosis as an unexpected cause of a focal liver lesion in a patient with hepatitis C and liver cirrhosis: a case report. Cases J 2009;2:8335. 5. Rizzo S, Monfardini L, Belmonte M, et al. Benign splenosis mimicking peritoneal seeding in a bladder cancer patient: a case report. Cases J 2009;2:9294. 6. Onuki T, Terao H, Muraoka K, et al. Splenosis mimicking local recurrence after radical nephrectomy: a case report of two cases. Hinkyokika Kiyo 2008;54:353– 6. 7. Gunes I, Yilmazlar T, Sarikaya I, et al. Scintigraphic detection of splenosis: superiority of tomographic selective spleen scintigraphy. Clin Radiol 1994;49:115–7. 8. Van Nostrand D, Corley JH, Kyle RW, et al. Value of selective spleen scintigraphy when liver/spleen image shows equivocal spleen defects: concise communication. J Nucl Med 1983;24:559 – 62. 9. Schiff RG, Leonidas J, Shende A, et al.The noninvasive diagnosis of intrathoracic splenosis using technetium-99m heat-damaged red blood cells. Clin Nucl Med 1987;12:785–7. 10. Schillaci O, Filippi L, Danieli R, et al. Single-photo emission computed tomography/computed tomography in abdominal diseases. Semin Nucl Med 2007;37:48 – 61. 11. Alvarez R, Diehl KM, Avram A, et al. Localization of splenosis using 99m Tc-damaged red blood cell SPECT/CT and intraoperative gamma probe measurements. Eur J Nucl Med Mol Imaging 2007;34:969.
© 2011 Lippincott Williams & Wilkins
12. Valdes RA, Horenblas S, Kartachova M, et al. 99m Tc-labelled heat-denatured erythrocyte SPET-CT matching to differentiate accessory spleen from tumour recurrence. Eur J Nucl Med Mol Imaging 2004;31:150. 13. Horger M, Eschmann SM, Lengerke C, et al. Improved detection of splenosis in patients with haematological disorders: the role of combined transmission-emission tomography. Eur J Nucl Med Mol Imaging 2003;30:316 –9. 14. Fleming CR, Dickson ER, Harrison EG Jr. Splenosis: autotransplantation of splenic tissue. Am J Med 1976;61:414 –9. 15. Lansdale N, Marven S, Welch J, et al. Intra-abdominal splenosis following laparoscopic splenectomy causing recurrence in a child with chronic immune thrombocytopenic purpura. J Laparoendosc Adv Surg Tech A 2007;17:387–90. 16. Stobie GH. Splenosis. Can Med Assoc J 1947;56:374 –7. 17. Sirinek KR, Livingston CD, Bova JG, et al. Bowel obstruction due to infracted splenosis. South Med J 1984;77:764 –7. 18. Basile RM, Morales JM, Zupanec R. Splenosis: a case of massive gastrointestinal hemorrhage. Arch Surg 1989;124:1087–989. 19. Varma DG, Campeau RJ, Kartchner ZA, et al. Scintigraphic detection of splenosis causing ureteral compression and hydronephrosis. Am J Roentgenol 1991;156:406. 20. Cordier JF, Gamondes JP, Marx P, et al. Thoracic splenosis presenting with hemoptysis. Chest 1992;102:626 –7.
249
Intra-Abdominal Splenosis Mimicking Metastatic Cancer Nicholas J. Short, BA, Teresa G. Hayes, MD, PhD and Peeyush Bhargava, MD
Abstract: Splenosis, the heterotopic autotransplantion of splenic tissue, is a common benign condition among patients with a history of splenic trauma. Most cases of splenosis are intra-abdominal due to direct seeding of surrounding structures, although these ectopic rests may occur almost anywhere in the body, and its diffuse nature may raise the suspicion of metastatic cancer. Confirmation of splenic tissue can be made by technetium-99m (Tc-99m) sulfur colloid scintigraphy or with Tc-99m heat-damaged red blood cells; however, in some cases, biopsy may be required for definitive diagnosis. Here, the authors present a patient with a remote history of posttraumatic splenectomy who was discovered to have multiple intra-abdominal nodules by CT scan. A diagnosis of diffuse metastatic disease was initially considered before a diagnosis of intraabdominal splenosis was ultimately made with the aid of Tc-99m sulfur colloid single-positron emission computed tomography (SPECT) and computed tomography imaging. Key Indexing Terms: Splenosis; Abdominal mass; Tc-99m sulfur colloid scintigraphy; SPECT-CT. [Am J Med Sci 2011;341(3):246–249.]
A
CASE REPORT
60-year-old Caucasian man was referred to an oncology clinic for suspected diffuse metastatic disease of unknown primary. He had recently been treated for a urinary tract infection, and a computed tomography (CT) scan was ordered when the microscopic hematuria on repeat urinalysis had not resolved after a complete course of antibiotics. This CT scan revealed numerous soft tissue masses within the abdomen and pelvis. The patient’s medical history was remarkable only for a splenectomy at the age of 5 years following an injury sustained from a fall from a ladder. He had smoked 2 to 3 packs of cigarettes daily for the past 35 years, and his family history was significant for colon cancer in his paternal grandfather and breast cancer in his mother and maternal aunt. The patient had never had a colonoscopy. He had no complaints except for concern that he may have cancer. He denied fever, chills, night sweats, weight loss, headaches, chest pain, shortness of breath, abdominal pain, change in bowel habits or gross hematuria. Physical examination revealed no abnormalities, and laboratory tests (including complete blood count with differential, comprehensive metabolic panel, urinalysis with microscopy and prostate specific antigen) were unremarkable. The CT scan was repeated, and it confirmed the presence of multiple soft tissue nodules ranging from 1.7 to 4.6 cm diffusely scattered within the abdominopelvic cavity. No normal appearing spleen was identified; however, a splenule was noted in the left upper quadrant. Given the patient’s history of traumatic splenic rupture requiring splenectomy, a diagnosis of splenosis was suspected. Liver-spleen scintigraphy was performed by injection of 8.7
From the Departments of Hematology/Oncology (NJS, TGH) and Radiology (PB), Baylor College of Medicine, Houston, Texas. Submitted July 27, 2010; accepted in revised form October 13, 2010. Correspondence: Nicholas J. Short, BA, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 (E-mail: [email protected]).
246
mCi of technetium-99m (Tc-99m) sulfur colloid, and planar images of the abdomen and pelvis in anterior and posterior projections were obtained 15 minutes after injection (Figure 1). Single-positron emission computed tomography (SPECT)-CT fusion imaging was also performed (Figure 2), which showed uptake of all nodules visualized by previous CT scan except for 1 large 4.6 ⫻ 2.7 cm nodule abutting the left lobe of the liver. An ultrasound-guided biopsy of this nodule revealed red blood cells, lymphoid aggregates and sinusoids without any evidence of malignant cells, confirming ectopic splenic tissue. A final diagnosis of intra-abdominal splenosis was made, and the patient was much reassured to learn he did not have widespread cancer.
DISCUSSION Splenosis is the benign heterotopic autotransplanation of splenic tissue, most commonly following traumatic rupture of the spleen. It has been estimated that blunt trauma accounts for up to 93% of cases of splenosis1 and that some amount of splenosis results from up to two thirds of significant splenic injuries.2 The misplaced splenic tissue of splenosis should be differentiated from that of accessory spleens, which are common, benign, congenital ectopic rests of functional splenic tissue that have been estimated to occur in 10% to 30% of the population.2 Because these accessory spleens form during embryological development, they are generally found near the spleen proper. In contrast, the dominant mechanism proposed to explain splenosis is that following significant trauma to the spleen, pieces of splenic tissue are dislodged from the spleen proper and seed surrounding structures. Thus, most of these splenic implants occur in the abdominopelvic cavity, as illustrated in the patient presented here. Thoracic splenosis is the most frequently reported of the extra-abdominal cases of splenosis,3 and all reported cases of thoracic splenosis have been accompanied by a known history of diaphragmatic rupture.1 The unfamiliarity of this condition among many clinicians can lead to much confusion in the diagnosis of a patient presenting with imaging that shows multiple intra-abdominal soft tissue nodules, as occurred in the patient presented above. In such a case, a number of disease entities must be considered, including abdominal lymphoma, metastatic carcinoma, peritoneal carcinomatosis, generalized adenopathy, endometriosis and multiple hemangiomas.1 Additional disease processes must be considered in a patient with thoracic nodules. Although the radiographic appearance of these nodules is often nonspecific, a history of elective splenectomy or splenic injury requiring splenectomy should raise the possibility of splenosis, especially in cases without historical or physical evidence suggestive of other diagnoses. This point is especially salient in the patient presented above, as his good health, lack of constitutional symptoms and the eventual resolution of his microscopic hematuria—the only localizing sign or symptom by history and physical examination—significantly decreased the likelihood of serious pathology.
The American Journal of the Medical Sciences • Volume 341, Number 3, March 2011
Intra-Abdominal Splenosis
FIGURE 1. Tc-99m sulfur colloid scintigraphy images of the abdomen and pelvis in anterior (A) and posterior (B) projections. Increased uptake of radioactive tracer is noted in 3 discrete areas within the abdominal cavity.
Early consideration and diagnosis of this benign condition can prevent the use of invasive diagnostic procedures and reduce the patient’s anxiety about potential malignancy. In addition, identification of splenosis is especially important in patients with a known primary malignancy, as differentiation of this benign condition from diffuse metastatic disease will impact staging and treatment decisions in many cases. This has been illustrated in case reports of patients with bladder cancer,4 renal cell carcinoma5 and Hodgkin’s disease2 in which unnecessary chemotherapy has been avoided by distinguishing splenosis from metastatic disease or disease recurrence. Similar considerations must be made even in patients at high risk for malignancy but with a remote history of splenic trauma, as demonstrated in a case of intrahepatic splenosis mimicking hepatocellular carcinoma in a patient with hepatitis C and cirrhosis.6 When a diagnosis of splenosis is considered, nuclear scintigraphy is the preferred method of diagnosis. The first imaging modality described for this purpose was Tc-99m sulfur colloid scintigraphy; however, recent research has shown that a nuclear scan using Tc-99m heat-damaged red blood cells is more sensitive and specific for splenic tissue.1,7 The proposed basis for this increased accuracy is that splenic tissue takes up only 10% of sulfur colloid but 90% of damaged red blood cells.7 In addition, sulfur colloid scans have been shown to have especially poor visualization of splenic tissue when the liver and splenic tissue overlap, whereas heat-damaged red blood cells have less uptake by the liver and are thus less susceptible to signal interference by surrounding liver parenchyma.7–9 The poor visualization by sulfur colloid scintigraphy of splenic tissue abutting the liver is illustrated in the false-negative result obtained in the patient presented here. However, despite these advantages of nuclear imaging with heat-damaged red blood cells, sulfur colloid scintigraphy is more commonly used by radiologists for confirmation of ectopic splenic tissue due to familiarity with the procedure and its relative ease of use. In cases of suspected ectopic splenic tissue, the addition of SPECT-CT fusion imaging can allow for 3-dimensional anatomical correlation, which is especially beneficial when surgical intervention may be required or when localization is otherwise ambiguous with nuclear scintigraphy alone.10 Previous reports have shown SPECT-CT to be useful in the localization of splenic implants in cases of refractory immune thrombocytopenia purpura11 and in distinguishing accessory spleens from intra-abdominal malig© 2011 Lippincott Williams & Wilkins
nancy.12 However, although SPECT alone has long been used in the identification of splenosis, to our knowledge, there is only 1 previous report illustrating the utility of SPECT-CT fusion imaging in distinguishing splenosis from malignancy.13 Therefore, this report further elucidates the utility of SPECT-CT in diagnosing splenosis and differentiating it from other causes of intra-abdominal soft tissue masses. Finally, despite the available methods for radiological diagnosis, sometimes a biopsy of suspected ectopic splenic tissue is needed to give full diagnostic certainty of splenosis rather than some potentially serious pathology. Although biopsy of the spleen proper is often avoided due to a high risk of bleeding, biopsy of the splenic implants of splenosis is considered a safe procedure—as long as they can be easily accessed—and to our knowledge, there are no reports in the literature of significant complications from such a biopsy. Of note, the blood supply of the ectopic splenic tissue of splenosis differs significantly from that of the spleen proper, as these ectopic rests derive their blood supply from penetrating blood vessels of the surrounding tissue rather than from the splenic artery.1 The difference in blood supply of these 2 biopsy sites could possibly account for any differences in bleeding rates that may exist. In most cases, splenosis is a benign, asymptomatic condition that does not require treatment. In fact, the diagnosis is usually not considered until suspicious findings are seen on imaging performed in the course of evaluating unrelated symptoms. This is illustrated in the patient presented here who was diagnosed with splenosis after undergoing a CT scan for microscopic hematuria. It should be noted that despite the urinary tract infection and microscopic hematuria eventually leading to a diagnosis of splenosis, there is no evidence in this case that any causal relationship exists between these findings. Although, in theory, splenic implants located along the urinary tract could cause obstruction and thus predispose to urine stasis and bacterial growth, in this patient, no splenic nodules were identified near the urinary system by SPECT-CT imaging; however, a splenic implant somewhere along the urinary system large enough to cause obstruction but too small to be visualized by CT scan cannot be entirely excluded. The patient’s hematuria is also not easily explained by splenosis. As splenosis is not an invasive process, any splenic implants— even if located around the urinary tract—would not be expected to cause hematuria. Furthermore, the eventual resolution of the
247
Short et al
FIGURE 2. SPECT-CT imaging of the abdomen (coronal, sagittal and axial sections) better characterizes the precise locations of the nodules seen by Tc-99m sulfur colloid scintigraphy. The nodule in the left upper quadrant (A) correlates with the splenule seen on a previous CT scan. The nodules in the anterior mesentery (B) and right lower quadrant (C) both correlate with intra-abdominal soft tissue nodules seen with previous CT imaging.
patient’s hematuria suggests that it was likely due to some transient process—most likely his preceding urinary tract infection—rather than splenosis. Although usually asymptomatic, in certain circumstances, surgical removal of ectopic splenic implants may be indicated. For example, there have been case reports of resolution of Felty’s syndrome,14 immune thrombocytopenia purpura15 and autoimmune hemolytic anemia16 after resection of the splenic implants of splenosis. Furthermore, although usually asymptomatic, there are reports of splenosis presenting with acute abdominal pain due to infarction,14 intestinal obstruction,17 gastrointestinal hemorrhage,18 ureteral compression19 or hemoptysis in the case of thoracic splenosis.20 In any
248
of these cases, removal of this misplaced splenic tissue may be necessary for symptomatic relief. REFERENCES 1. Fremont RD, Rice TW. Splenosis: a review. South Med J 2007;100: 589 –93. 2. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 29 –1995. A 65-year-old man with mediastinal Hodgkin’s disease and a pelvic mass. N Engl J Med 1995;333: 784 –91. 3. Sahin E, Karadayi S, Nadir A, et al. Thoracic splenosis accompanied by diaphragmatic hernia. Can J Surg 2009;52:E293– 4.
Volume 341, Number 3, March 2011
Intra-Abdominal Splenosis
4. Menth M, Herrmann K, Haug A, et al. Intra-hepatic splenosis as an unexpected cause of a focal liver lesion in a patient with hepatitis C and liver cirrhosis: a case report. Cases J 2009;2:8335. 5. Rizzo S, Monfardini L, Belmonte M, et al. Benign splenosis mimicking peritoneal seeding in a bladder cancer patient: a case report. Cases J 2009;2:9294. 6. Onuki T, Terao H, Muraoka K, et al. Splenosis mimicking local recurrence after radical nephrectomy: a case report of two cases. Hinkyokika Kiyo 2008;54:353– 6. 7. Gunes I, Yilmazlar T, Sarikaya I, et al. Scintigraphic detection of splenosis: superiority of tomographic selective spleen scintigraphy. Clin Radiol 1994;49:115–7. 8. Van Nostrand D, Corley JH, Kyle RW, et al. Value of selective spleen scintigraphy when liver/spleen image shows equivocal spleen defects: concise communication. J Nucl Med 1983;24:559 – 62. 9. Schiff RG, Leonidas J, Shende A, et al.The noninvasive diagnosis of intrathoracic splenosis using technetium-99m heat-damaged red blood cells. Clin Nucl Med 1987;12:785–7. 10. Schillaci O, Filippi L, Danieli R, et al. Single-photo emission computed tomography/computed tomography in abdominal diseases. Semin Nucl Med 2007;37:48 – 61. 11. Alvarez R, Diehl KM, Avram A, et al. Localization of splenosis using 99m Tc-damaged red blood cell SPECT/CT and intraoperative gamma probe measurements. Eur J Nucl Med Mol Imaging 2007;34:969.
© 2011 Lippincott Williams & Wilkins
12. Valdes RA, Horenblas S, Kartachova M, et al. 99m Tc-labelled heat-denatured erythrocyte SPET-CT matching to differentiate accessory spleen from tumour recurrence. Eur J Nucl Med Mol Imaging 2004;31:150. 13. Horger M, Eschmann SM, Lengerke C, et al. Improved detection of splenosis in patients with haematological disorders: the role of combined transmission-emission tomography. Eur J Nucl Med Mol Imaging 2003;30:316 –9. 14. Fleming CR, Dickson ER, Harrison EG Jr. Splenosis: autotransplantation of splenic tissue. Am J Med 1976;61:414 –9. 15. Lansdale N, Marven S, Welch J, et al. Intra-abdominal splenosis following laparoscopic splenectomy causing recurrence in a child with chronic immune thrombocytopenic purpura. J Laparoendosc Adv Surg Tech A 2007;17:387–90. 16. Stobie GH. Splenosis. Can Med Assoc J 1947;56:374 –7. 17. Sirinek KR, Livingston CD, Bova JG, et al. Bowel obstruction due to infracted splenosis. South Med J 1984;77:764 –7. 18. Basile RM, Morales JM, Zupanec R. Splenosis: a case of massive gastrointestinal hemorrhage. Arch Surg 1989;124:1087–989. 19. Varma DG, Campeau RJ, Kartchner ZA, et al. Scintigraphic detection of splenosis causing ureteral compression and hydronephrosis. Am J Roentgenol 1991;156:406. 20. Cordier JF, Gamondes JP, Marx P, et al. Thoracic splenosis presenting with hemoptysis. Chest 1992;102:626 –7.
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