Primary ALK-Positive Large B Cell Lymphoma of Pancreas

Primary pancreatic B-cell lymphoma is rare with most common type being Diffuse Large B-cell lymphoma (DLBCL). Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+ LBCL) represents less than 1% of all DLBCL. Extra-nodal presentation is rare with presentation as a primary pancreatic mass being exceptional.

A 42 years female presented with lump in central upper abdomen for one month with evidence of icterus. Lab Investigations showed deranged Total Bilirubin/Direct Bilirubin, AST, ALT, ALP, Amylase, Lipase, CEA, CA 19-9 and CA-125 levels. CECT scan showed large solid mass in pancreas with necrotic areas within. Biopsy revealed a lymphoma with strong expression of ALK (granular cytoplasmic), CD138, MUM1, kappa, moderate expression of CD45 and focal expression of CD20, CD79a and PAX5 and lack of expression of CD5, CD3, CD45RO, BCL6, CD10 and EMA. FNAC and Flow Cytometry was also performed. A final diagnosis of ALK positive LBCL was made with pancreas as primary.

Present case is the first case of ALK positive LBCL reported in pancreas. Expression of mature B-cell markers such as CD20, CD79a and light chain restriction may be seen unlike previous claims.