A case of inflammatory pseudotumor in the spleen.

Abstract: A case of an inflammatory pseudotumor of the spleen is presented. A 43-year-old woman was hospitalized for a detailed examination due to pancytopenia, which was diagnosed during an examination related to left upper quadrant abdominal pain. Physical examination revealed a 2 to 3 cm splenomegaly. Reticulocyte count was 4% and erythrocyte sedimentation rate was 55 mm/h. No other important findings were noted, except for an evident increase in myeloid series and megakaryocytes (more evident in erythroid series) on bone marrow aspiration and biopsy. Computed tomography (CT) scan revealed splenomegaly and a centrally located hypodense lesion with a 92 x 86 mm axial diameter in the spleen. With a hematologic malignancy prediagnosis, a splenectomy was performed on the patient because of pancytopenia and splenomegaly. An intrasplenic, centrally located, well-limited, capsulated lesion (9.5 x 11 x 10 cm in diameter) was discovered on macroscopic examination of the material. A cellular infiltration area was seen on microscopic examination. The spleen capsule was mildly fibrotically thickened. The lesion that separated from the spleen tissue consisted of diffusely proliferated fusiform fibroblasts, heterogenous inflammatory cells consisting mainly of plasma cells, lymphocytes, sparse neutrophils and vascular elements. No granuloma or multinuclear giant cells were detected. Pancytopenia improved on follow-up. The patient followed up for two years, is now healthy and has no complaints.

Key Words: inflammatory pseudotumor, spleen

Case Report

A 43-year-old woman was hospitalized for a detailed examination due to pancytopenia that was diagnosed during an examination related to left upper quadrant abdominal pain. On physical examination, there were no important findings other than slight conjunctival paleness, ecchymotic lesions in her lower extremities, and a 2 to 3 cm splenomegaly.

Laboratory findings were as follows: hemoglobin: 10.6 g/dL; hematocrit: 31.7%; total leukocyte count: 3.100/[micro]L (66% neutrophils. 30% lymphocytes, 3% monocytes, 1% eosinophils): MCV: 81 fL; MCH: 27.1 pg; MCHC: 33.4 g/dL; thrombocyte count: 45,000/[micro]L; reticulocyte count 4%; and erythrocyte sedimentation rate: 55 mm/h. Blood biochemical examination. PTT (prothrombin time) and aPTT (activated prothrombin time) were all within normal ranges.

No other important findings were noted except for an evident increase in myeloid series and megakaryocytes (more evident in erythroid series) on bone marrow aspiration and biopsy. Splenomegaly and a hypoechogenic lesion in the spleen were determined on abdominal ultrasonography. Axial diameter of the spleen was determined to be 124 x 10 mm (increased diameter) on a computed abdominal tomography. A centrally located hypodense lesion with 92 x 86 mm axial diameter was discovered in the spleen (Fig. 1).

With a hematologic malignancy prediagnosis, a splenectomy was performed because of pancytopenia and splenomegaly. In the macroscopic examination of the splenectomy specimen, an intrasplenic, centrally located, well-circumscribed mass measuring 9.5 x 11 x 10 cm was observed. The mass was gray-yellow on cut surface. On the microscopic examination, it was detected that the lesion was composed of a mixture of fibroblasts and a mixed inflammatory infiltrate consisting of histiocytes, plasma cells, lymphocytes and a few neutrophilic leukocytes. Areas of variable degrees of fibrosis and hyalinization were also detected (Fig. 2). The lesion had infiltrative borders and there was no capsule between the splenic parenchyma and the lesion. There was trabecular thickening, reactive changes in the white pulp and congestion in the sinuses of the red pulp in the splenic tissue adjacent to the lesion. No granuloma or multinuclear giant cells were detected.

The patient had no postoperative complications until the 7th postoperative day, at which time thrombocytosis developed. Pancytopenia improved at follow-up. The patient followed up for 2 years, is now healthy and has no complaints.

Discussion

Inflammatory pseudotumor is a rarely encountered lesion that is formed by the irregular proliferation of inflammatory cells. It is a benign lesion, although it seems to be a malignant lesion on clinical and radiological examinations. (1) Although the reason is not clearly known, it is a reactive lesion which develops due to vascular thrombosis, infectious or autoimmune reasons. (2) Epstein-Barr virus and HIV has been found to be responsible for this lesion in some publications. (1,3,4) It is generally encountered in the orbital, spinal meninges, gastrointestinal system, heart, soft tissues, mesothelial membranes and the respiratory system. (5,6) It is rarely located in the spleen; however, in recent years, a splenic localization has been reported at gradually increasing rates. They are initially evaluated as malignant lesions by the clinician, as they present as mass lesions. (7,8) Pathologically, they are often confused with lymphoproliferative diseases. (1,3) Metastasis, highly severe necrosis, local recurrence, atypical giant cell, surgical phase, number of cells, and presence of 3 or more mitoses are important in the prognosis. The factor most affecting the prognosis is metastasis. Local recurrence and necrosis are the other independent factors. Generally, splenic inflammatory pseudotumors are accidentally determined during the examinations for other diseases. Symptomatic patients most frequently present with left upper quadrant abdominal pain. Symptoms like anemia, epigastric sensitivity and fever may also exist in patients. Symptoms seem to correlate with the size of the lesion. Most of the lesions are solitary but they may be multinodular. Their size can vary from 0.3 to 12.7 cm. The weight of the spleen can vary from 40 to 1,363 g. (9) It has been reported in some publications that the size of the spleen gradually increases. (10) Clinical, biochemical and radiologic examinations are required to make an "inflammatory pseudotumor" diagnosis. Ultrasonography, CT and magnetic resonance (MR) scintigraphy are used for radiologic diagnosis. There are some studies showing that ultrasonography and MR may be insufficient in the diagnosis (11) and scintigraphic examinations with Tc-99m colloid SPECT and Ga-67 are better than other methods. (12) A histopathological examination is required to differentiate a hematologic malignancy. Splenectomy may be performed for diagnosis but there are cases that are diagnosed by fine needle aspiration biopsy (FNA) after angiography. (13) The most common findings in the microscopic examination are proliferation of fusiform spindle cells and inflammatory cell infiltration with variable severities. (14) Inflammatory pseudotumors consist of especially inflammatory cells like mature lymphocytes, plasma cells and histiocytes. Pathologic diagnosis is required for the differentiation from lymphoproliferative spleen diseases. (5) Characteristic inflammatory polymorph and fibroblastic infiltration seen in the immunohistochemical examination show that the lesion is benign. (15) Surgical excision is curative. Performing examinations like respiratory function tests, upper abdominal CT and hepatic function tests before the operation is important in the diagnosis of other pseudotumors.

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References

1. Lado Lado FL, Paramo de Vega M, Torre Carballada JA, et al. Inflammatory pseudotumor of the spleen. An Med Interna 2004;21:279-282.

2. Yesildag E, Sarimurat N, Ince U, et al. Nonsurgical diagnosis and management of an inflammatory pseudotumor of the spleen in a child. J Clin Ultrasound 2003;31:335-338.

3. Spivach A, Martinolli S, Adornetto R, Melato M. Inflammatory pseudotummour of the spleen: a case report and review of the literature. Chir Ital 2005;57:655-660.

4. Oz Puyan F. Bilgi S, Unlu E, et al. Inflammatory pseudotumor of the spleen with EBV positivity: report of a case. Eur J Haematol 2004;72:285-291.

5. Braun B, Cazorla A, Rivas C, et al. Inflammatory pseudotumor of the spleen in a patient with human immunodeficiency virus infection: a case report and review of the literature. Ann Hematol 2003;82:511-514.

6. Suga K, Miura K, Kume N, et al. Tc-99m colloid and Ga-67 imaging of splenic inflammatory pseudotumor correlation with ultrasound, CT, and MRI. Clin Nucl Med 1999 May;24:334-337.

7. Koh MB, Chae HS, Oh YK. et al. A case of inflammatory pseudotumor of the spleen. Korean J Gastroenterol 2003;42:168-171.

8. Alimoglu O, Cevikbas U. Inflammatory pseudotumor of the spleen: report of a case. Surg Today 2003;33:960-964.

9. Chen WH, Liu TP, Liu CL, Tzen CY. Inflammatory pseudotumor of the spleen. J Chin Med Assoc 2004;67:533-536.

10. Venizelos 1, Tamiolakis D, Simopoulos C, et al. Inflammatory pseudotumor of the spleen. Chirurgia (Bucur) 2004;99:265-268.

11. Yeung E, Hugh TB, Rainer S. Inflammatory pseudotumour of the spleen. Aust N Z J Surg 1996;66:492-493.

12. Thomas RM, Jaffe ES, Zarate-Osorno A, et al. Inflammatory pseudoptumor of the spleen. Arch Pathol Lab Med 1993;117:921-926.

13. Moriyama S, Inayoshi A, Kurano R. Inflammatory pseudotumor of the spleen: report of a case. Surg Today 2000;30:942-946.

14. Hayasaka K, Soeda S, Hirayama M, Tanaka Y. Inflammatory pseudotumor of the spleen: US and MRI findings. Radiat Med 1998;16:47-50.

15. Ejeckam G, Abdulla F, Azadeh B. Burns B. Inflammatory pseudotumor of the spleen: a case report. East Afr Med J 1994;71:273-274.

Sorrow is so easy to express and yet so hard to tell.
--Joni Mitchell

Aslan Celebi, MD, Seyit Mehmet Kayacan, MD, Serkan Keskin, MD, Ela Temeloglu, MD, Deniz Koc, MD, Vildan Ercan, MD, Deniz Esin, MD, Ismail Ekizoglu, MD, Sezai Vatansever, MD, Mine G. Gulluoglu, MD, and Osman Erk, MD

From the Department of Internal Medicine, Taksim Education and Research Hospital, and the Departments of Internal Medicine and Pathology, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey.

Reprnt requests to Dr. Seyit Mehmet Kayacan, Cahslar cad. Karaoglan sokak, Kamelya Apartment, 36/12 Bahcelievler, Istanbul. Turkey. Email: [e-mail]

Accepted February 6, 2006.

RELATED ARTICLE: Key Points

* Inflammatory pseudotumour is a benign lesion although it seems to be a malign lesion in clinical and radiological examinations.

* Although its reason is not clearly known, it is a reactive lesion developed due to vascular thrombosis, infectious (EBV, HIV, etc) or autoimmune reasons.

* It is generally encountered in the orbital, spinal meninges, gastrointestinal system, heart, soft tissues, mesothelial membranes and respiratory system but is rare in the spleen.

* Pathologically, they are confused with especially lymphoproliferative diseases, but are differentiated by proliferation of fusiform spindle cells and inflammatory cell infiltration with variable severities.

* Surgical excision is curative.