Primary Splenic Lymphoma Presenting As Splenic Abscess: A Rare Entity

Primary splenic lymphoma are rare lymphomas which comprise less than 1% of the all malignant lymphoma. We present a case of 35 years old female with fever and pain in abdomen for a period of 20 days. The main purpose of this paper is to report a rare occurrence of primary splenic lymphoma and to demonstrate the possibility of it being misdiagnosed as splenic abscess clinically and on imaging. Case Report *Corresponding author: Dr Noora Saeed, Department of Pathology, JNMC, AMU, Aligarh,U.P, INDIA, Phone: +91 9997240844 E-mail: [email protected] C-208 Primary Splenic Lymphoma presenting as Splenic Abscess Annals of Pathology and Laboratory Medicine, Vol. 03, No. 04, October December 2016 Introduction Non-Hodgkin lymphoma (NHL) originates from lymphovascular system and can be classified as B cell lymphomas (about 90% of all NHL) and T cell lymphomas (10% of all NHL).[1] Since spleen is the major site for filtration of blood so primary tumors of spleen are generally haematological malignancies, in which most are lymphomas.[2] However primary splenic lymphoma (PSL) is an extremely rare neoplasm with a reported incidence of less than 1%.[3] To define primary splenic lymphoma, the lymphoma should be confined to the spleen and/or splenic hilar lymph nodes, although few authors also accept the presence of bone marrow involvement.[4] Histomorphologically great majority of cases are of B-cell type, with diffuse large B-cell lymphoma being the most common.[5] PSL of spleen is difficult to diagnose with the common differentials being hemangioma, lymphangioma, abscess, hamartoma, infarct and metastatic disease.[6] The patients usually present with abdominal pain or mass due to splenomegaly, with or without fever, systemic upset, or thrombocytopenia.[4]. Here, we present a case of PSL in a 35-year-old female patient, which was initially diagnosed as splenic abscess. Case Report A 35-year-old female patient presented with fever and pain abdomen for 20 days. General examination revealed the presence of mild pallor. On abdominal examination, spleen was palpable approximately 7 cm below the left costal margin. On palpation spleen was nodular and firm in consistency. No other significant systemic finding was noted. Complete blood count of patient revealed microcytic hypochromic anemia (hemoglobin level 10 g/dL). The total and differential counts were within normal limits. ESR was found to be raised. Other routine investigations including liver function test, renal function test, and lactate dehydrogenase levels were within the normal limits. An ultrasonogram of the abdomen revealed single well circumscribed, lobulated hypoechoeic lesion which favoured the diagnosis of splenic abscess. The computed tomographic findings of abdomen revealed a circumscribed rounded, low attenuated lesion (figure 1a&1b). For splenomegaly the patient underwent splenectomy (figure 1c). Grossly spleen measured 12x10x9cms and weighed 1.3kg. Cut section revealed a single white nodule mixed with necrotic areas, involving almost whole of the spleen and measuring 11x 9x9cm (figure 1d). Imprint cytology of the specimen showed many degenerated atypical cells with prominent nucleoli mixed with inflammatory cells and necrosis (figure 2a). Histopathology showed diffuse sheets of large sized cell with central vesicular nucleus, prominent nucleolus, focally prominent and atypical mitotic activity. Section also showed large areas of ischemic necrosis mixed with neutrophilic infiltrate (figure 2b&2c). Immunohistochemistry revealed positivity for CD 20 (figure 2d) while tumor cells were negative for CD5 and CD10. Following this a final diagnosis of DLBCL was made. The patient had received six cycles of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) postoperatively and was disease free and was on regular follow up for seven months. Discussion The definition of PSL is variable and remains a matter of controversy. The earliest definition was given by Dasgupta et al., who defined PSL as a condition confined to spleen or hilar lymph nodes with no recurrence of disease for at least 6 months after splenectomy.[7] In the present case, the patient fulfilled the criteria of this definition. On the other hand, Skarin et al [8] and Kehoe J et al [9] suggested that the diagnosis of PSL be made if splenomegaly is a predominant feature in any lymphoma involving the spleen. While Kraemer et al [10] recommended the diagnosis of PSL, as patients with splenomegaly, cytopaenia of at least two haematological cell lines and the absence of peripheral adenopathy. The etiology of splenic lymphoma largely remains unknown. However it has been suggested that chronic hepatitis due to hepatitis C virus infection along with some poorly defined genetic and environmental factors play a significant role in its development.[11] Symptoms of PSL may be variable, with few presenting as fever, weight loss, weakness and left upper quadrant discomfort, mimicking clinically as splenic abscess.[12] In the present case, the patient presented with fever along with pain abdomen and splenomegaly. Among the lab findings, significant features include cytopenia or increased ESR or b2 microglobulin level. [13] In our case also the patient had increased ESR along with microcytic hypochromic anemia. The radiological investigation of choice for the diagnosis is contrast enhanced computed tomography (CECT), in which the lesions appear hypoechoic, but sometimes anechoic areas may be seen, which suggest liquefactive necrosis thereby causing confusion with splenic abscess.[8] In our case both clinical presentation and imaging studies mimicked splenic abscess. The common differential diagnoses of solitary splenic lesion include hemangioma, lymphangioma and hamartoma.