An Uncommon Cause of Splenomegaly

A 55-year-old man presented with pain in the left flank for the last 8 months with history of significant weight loss. The pain was relieved on assuming a knee-chest position. On clinical examination the patient was afebrile with mild tenderness in the left hypochondrium. There was no icterus or lymphadenopathy. The spleen was palpable 6 cm below the costal margin and was firm and non-tender. There was no hepatomegaly and thorough clinical examination failed to reveal any lymphadenopathy. Baseline hematological investigations were (Hb=11.6 gm/dl, WBC=8000/ cumm and a differential count of 64% neutrophils, 30% lymphocytes, 3% eosinophils and 3% monocytes, platelet count 150×103 mm3. His erythrocyte sedimentation rate (ESR) was elevated with 52 mm at the end of the first hour. Liver function tests and renal function tests were within normal limits. His chest radiograph was within normal limits. Abdominal ultrasonograghy (USG) revealed an enlarged spleen measuring 20×15 cm with multiple hypoechoic lesions. An abdominal computed tomography (CT) revealed a hypodense splenic mass with multiple splenic hilar lymphadenopathies. His chest radiographs, abdominal USG, and CT did not reveal any other lymphadenopathy. Based on radiological findings, a provisional diagnosis of a malignant tumour possibly primary lymphoma of spleen was made. A bone marrow examination was done, which revealed a normal study. The patient underwent splenectomy with splenic hilar lymphadenectomy. The spleen along with the hilar lymph nodes was sent for histopathological examination. The specimen measured 23×16×10 cm and weighed 2 kg. Grossly the capsule of the spleen was intact. Cut surface revealed a nodular grayish-white infiltrative growth measuring 21×10×9 cm almost replacing the whole of the spleen (figure 1a). The growth had fish-flesh like appearance with areas of necrosis. Sections examined from the growth showed dispersed population of malignant cells present in sheets (figure 1b). The cells had high nucleo-cytoplasmic ratio, vesicular nuclei and single or multiple prominent nucleoli. Mitotic count was 6 per 10 hpf with many atypical mitosis seen. Scattered mature lymphocytes were present in the background of the tumor. Tumor cells were seen to infiltrate surrounding white pulp. However, the capsule was intact. Large areas of necrosis were also seen. On immunohistochemistry the tumor cells were positive for LCA and B-cell marker (CD20) (figures 1c and 1d) and negative for T-cell marker (CD45RO) and BCL-2 (fiures 1e 150