Aust. N.Z. J . Surg. (1996) 66,492-493

CASE REPORT

INFLAMMATORY PSEUDOTUMOUR OF THE SPLEEN

EDDIE YEUNG,* THOMAS B. HUGH* AND STEPHEN R A I N E R ~ Departments of *General Surgev and tAnatomical Pathology, St Vincent’s Hospital, Sydney,

New South Wales, Australia

Inflammatory pseudotumours are benign tumour-like masses of unknown aetiology that show microscopically a range of inflam- matory and reactive responses and are of importance because they may be mistakenly identified as neoplasms. This case report describes a 15 year old girl with a cystic inflammatory pseudotumour of the spleen in whom a partial splenectomy was performed with a satisfactory outcome.

Key words: spleen, tumour.

INTRODUCTION Although inflammatory pseudotumours have been reported in various locations, including the orbit,’ the respiratory tract? the salivary glands,’ the liver: the heart5 and the soft tissue: involvement of the spleen was not documented until 1984 when Cotelingam and Jaffe published two case report^.^ Since 1984, 22 cases of splenic pseudotumour have been reported, estab- lishing this benign lesion as a recognizable entity in the spleen.

CASE REPORT A previously well 15 year old girl developed sudden, severe, constant left subcostal pain while playing tennis. There had been no injury to the abdomen. The patient presented to her local doctor who detected only mild left upper quadrant abdominal tenderness. A subsequent computed tomographic (CT) scan showed a well- defined 7 cm cystic mass in the spleen (Fig. I ) . There was a localized area of increased density in the posteromedial wall of the mass without enhancement or other specific features. The density of the mass was thought to be inconsistent with a recent haematoma and no evidence of recent bleeding was seen in rela- tion to the cyst, the spleen or the adjacent structures. The size of the spleen was at the upper limit of normal. The other abdominal and retroperitoneal structures were considered completely normal. The diagnostic possibilities considered at that time were hydatid cyst, a congenital cyst, or cystic degeneration in an area of trauma. Hydatid serology was negative.

The pain gradually diminished during a period of several weeks. An upper abdominal ultrasound performed 4 weeks after CT scan demonstrated a cystic mass 3.0 X 3.1 X 3.2 cm in size in the anterior portion of the spleen, almost half the size of the previously demonstrated lesion. There then existed a thick and irregular wall, the contents of the cyst were echolucent, and no debris was seen. The margin of the spleen was clearly defined around the cyst. The most likely diagnosis was considered to be a cyst of the spleen, possibly congenital, which may have under- gone minor trauma. Surgical removal was advised due to the uncertainty of the diagnosis, the possibility of future haemor-

Dr Thomas B. Hugh, St Vincent’s Clinic, 438 Victoria Street, Darling- hurst, NSW 20 10. Australia.

Accepted for publication 17 February 1994.

Fig. 1. Computed tomographic scan showing cystic lesion in the spleen (arrowed).

rhage, and the risk of future malignant change in a splenic cyst. At laparotomy, 10 weeks after the onset of symptoms, there

were dense omental adhesions around the lower pole of the spleen, under which lay an indurated mass. The other intra-abdominal organs were normal. The adhesions were divided and a lower pole segmental resection of the spleen was performed using a TA-90 staple gun (US Surgical Corporation, Norwalk, CT. USA). Haemostasis was achieved without difficulty. Gross examination showed the lesion to be a well-encapsulated mass with a cystic centre containing a small amount of turbid fluid. No organism was cultured from this fluid. The patient’s postoperative recovery was unremarkable; she was discharged from hospital on the third postoperative day and has remained free of symptoms in the 24 months that followed.

Pathological examination showed the specimen to consist of an 80 X 65 X 25 mm wedge of spleen weighing 61 g. Within the perihilar splenic parenchyma there was a circumscribed yellow cystic mass 22 mm in maximum diameter. There were paler areas within the mass that appeared to extend outside the capsule to involve the hilar splenic fat. The remainder of the spleen was normal. Microscopically, the interface between spleen and mass was marked partially by pseudocapsule for- mation (Fig. 2) and partially by direct abutment. The mass was

PSEUDOTUMOUR OF THE SPLEEN 493

Fig. 3. Spindle-shaped cells containing patchy infiltrate of lym- phocytes and plasma cells (haematoxylin and eosin X 200).

composed predominantly of spindle-shaped cells arranged in poorly formed fascicles and in faintly storiform areas. These cells were relatively uniform in size and shape and resembled fibroblasts. There was no mitotic activity. Interspersed among these cells were groups of plasma cells, lymphocytes, histio- cytes with foamy cytoplasm, and small amounts of haemo- siderin (Fig. 3). No hilar lymph node was present. Centrally, a region of cystic degeneration was present. An inflammatory pseudotumour of the spleen was diagnosed.

DISCUSSION Pseudotumours of the spleen are rare; a review of the literature revealed only 22 cases.

The presentation of pseudotumours of the spleen varies, the most common symptom being left upper quadrant discomfort or pain; a palpable mass is present occasionally. The lesion has also been found as a result of an investigation of other illnesses in some patients. The age of the reported patients (including

this patient) ranges from 15 to 75 years.7-" Interestingly, a recent report by Shepherd et al. described a patient who had hypercalcaemia associated with an inflammatory pseudotumour of the spleen; the serum calcium level returned to normal fol- lowing splenectomy.lo

Pseudoturnours vary greatly in size and may be as large as 17 cm in diameter. They are usually solitary although several cases with multiple small tumour-like nodules have been reported. It has been suggested that in some patients large tumour masses may form from the union of smaller lesions and may, therefore, represent a different stage in pathogenesis." Our experience sup- ports the view that pseudotumours may decrease in size over time. Cystic degeneration, or central necrosis as noted in this case, seems to be a common feature in splenic pseudotumours, as is a tendency for the inflammatory change to infiltrate sur- rounding structures, also seen in our

The exact aetiology of inflammatory pseudotumours is unknown. Malignant transformation or metastatic spread has not been reported. The decrease in size of the mass in this patient sug- gests that the potential exists for spontaneous resolution, but resection is generally advised because of the difficulty of distin- guishing these lesions from true tumours. In the spleen it may not be possible pre-operatively to rule out serious lesions such as lym- phoma, inflammatory malignant histiocytoma, or sarcoidosis.

In all cases previously reported of inflammatory pseudo- turnour of the spleen where operation was undertaken, total splenectomy was performed. However, in this case, because of the age of the patient and the favourable location of the lesion, partial splenectomy was possible. In view of the apparently benign nature of these masses partial splenectomy seems appro- priate, if feasible technically, once the diagnosis has been con- firmed by frozen section examination.

I

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