Introduction

Primary sarcomas are the rarest among primary splenic malignant neoplasms [1]. Undifferentiated pleomorphic sarcoma (UPS), previously known as malignant fibrous histiocytoma (MFH), is a common soft tissue neoplasm in adulthood which usually affect extremities and retroperitoneum than visceral organs [2]. However, primary UPS/MFH of the spleen is extremely rare and less than 25 cases have been reported up to 2020 [1, 3, 4]. Splenic MFH/UPS is an aggressive tumour with poor prognosis which usually shows systemic metastases by the time of the presentation. Current practice is to excise the tumour with a negative histological margin even in recurrent or metastatic disease [5].

Case Report

A 52-year-old Sri Lankan female presented with generalised abdominal distension for 1 month. She complained of dyspepsia but never experienced haematemesis, melena or jaundice. She never had previous attacks of pancreatitis or previous abdominal surgery. She was pale, and on abdominal examination, there was a large tender epigastric mass extending up to the umbilicus. Patient was anaemic (haemoglobin 8.5 mg/dl) and showed marginal neutrophil leucocytosis. Liver biochemistry, serum amylase and bilirubin levels were normal.

Ultrasonographically, there was an epigastric mass probably arising from the spleen or the tail of the pancreas which predominantly consisted cystic lesions and a few solid areas. Cystic lesions contained echogenic debris with no internal vascularity. Minimal ascites was noted with no focal liver lesions. Computed tomography (CT) confirmed the mass to arise from the spleen and to have an irregular thick walled, well-defined cyst with peripherally solid areas. Furthermore, the mass was displacing the left lobe of the liver and the stomach and there were no calcifications (Fig. 1). Despite the pressure effect on surrounding viscera, there was no local invasion. Few enlarged lymph nodes were seen in para-aortic region. There were no omental, abdominal visceral or bone metastasis. The mass was considered a complex splenic cyst, a splenic abscess or a cystic splenic neoplasm. With the occurrence of elevated temperature and rising inflammatory markers, a splenic abscess in a complex cyst was considered the working diagnosis. The patient underwent an open splenectomy using a rooftop incision. Operative findings were of a large predominantly cystic mass of splenic origin with areas of concealed leaks; displacing stomach, left lobe of the liver and colon; forming adhesions to the diaphragm. Immediate postoperative period was uncomplicated.

Fig. 1
figure 1

Computed tomography images of the lesion. 1A and 1B shows the coronal and axial sections respectively. Also appreciate the displacement of surrounding organs (L, liver)

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The resected specimen showed a distorted spleen with a large, disrupted complex cyst measuring 10 × 10 cm (Fig. 2). Microscopy showed a necrotic, cystic tumour of splenic origin. There were viable foci of tumour within splenic parenchyma surrounding the cyst space (Fig. 3A and B). The tumour showed diffuse sheets of spindle to epithelioid cells arranged in storiform pattern in a loose myxoid stroma. The constituent cells contained oval to round hyperchromatic nuclei and short ill-defined eosinophilic cytoplasmic processes. Mitoses were abundant. Vascular emboli are present. The tumour was limited to the spleen. Pleomorphic cells were positive for Vimentin and negative for LCA, AE1/AE3, CD68, MPO, Desmin, CD34, CD31, CD99, S-100, HMB45 and Myogenin. Therefore, the tumour was concluded as an undifferentiated high-grade pleomorphic sarcoma.

Fig. 2
figure 2

Macroscopy of the sectioned specimen. Blue needle head shows the normal splenic segment

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Fig. 3
figure 3

Photomicrographs of the resected specimen. 3A, high-grade sarcoma within splenic parenchyma (haematoxylin and eosin × 10). 3B, undifferentiated sarcoma comprising fascicles of pleomorphic cells that lack specific immunohistochemical differentiation (haematoxylin and eosin × 40)

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The patient defaulted follow-up at 4 weeks from surgery and got readmitted after 3 months with generalised abdominal distention and ill health. Ultrasonography showed tumour recurrence on the surgical bed with liver, pelvic and peritoneal deposits. Patient deteriorated drastically and succumbed due to early tumour recurrence, 3 months after splenectomy.

Discussion

Limited number of cases of splenic MFHs/UPSs has been reported since the first description in 1982 (Table 1). Majority have presented with upper abdominal discomfort/pain and splenomegaly, with or without constitutional symptoms. There have been exceptional presentations with acute abdomen due to tumour rupture or haemorrhage [1, 6]. CT has been the main preoperative imaging method for assessment of cystic/solid lesions of the spleen in presence of MFH/UPS. Misleading working diagnosis of splenic abscesses and Echinococcosis/hydatidosis has been made due to the rarity of this entity [1, 4, 6].

Table 1 Summary of previously reported cases of MFH/UPS of spleen
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Since Theodor Billroth performed the first splenectomy for a soft tissue sarcoma in 1881, surgical resection with a histologically negative margin has been the mainstay of treatment for splenic sarcomas [5]. Despite achieving tumour-free margins, local recurrences have been common leading to poor survival outcomes (Table 1) [5, 6]. Adjuvant chemotherapy and radiotherapy have been used in splenic UPS/MFHs without much long-term survival [5]. Prognostic data is limited in these extremely rare malignancies. Within available data, the histological grade of the tumour seems to have higher influence on survival rather than tumour staging [1, 5, 6]. In poorly differentiated tumours, survival has been less than 1 year as in our case.

From a surgical point of view, this case highlights the need for the surgeons to be considerate of rare entities like splenic UPS as differential diagnosis, when patients present with splenomegaly and constitutional symptoms. Multidisciplinary approach would be essential to get the birds’ eye view of the clinical picture with the complexities in interpretation of imaging modalities in the presence of elevated inflammatory markers.