Alk-positive large B-cell lymphoma: a case report

Abstract

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+ LBCL) is a rare and aggressive lymphoma with fewer than 150 cases reported worldwide in the literature. It has a male predominance, a median age of 36 years, and typically presents with advanced stage disease. This case report is of a 50-year-old male who presented with chest pain and was found to have mediastinal lymphadenopathy in June 2018. The patient had a notable past medical history of acute promyelocytic leukaemia (APML) diagnosed in 2010. This was treated with anthracycline/ATRA chemotherapy, methotrexate and 6-mercaptopurine for 2 years with complete molecular remission from APML since July 2010. A core biopsy of the mediastinal lymph node showed a diffuse infiltrate of plasmablast-like cells. Immunohistochemistry was negative for B-cell markers and positive for plasma cell markers and ALK1. Break-apart FISH probe confirmed ALK rearrangement, consistent with a diagnosis of ALK+ LBCL. PET-CT staging demonstrated involvement of lymph nodes above and below the diaphragm, as well as multiple bony deposits. The patient completed 3 cycles of CHEOP-14 chemotherapy and achieved a near complete remission. This report describes a novel case of ALK+ LBCL and its management.