ALK-negative anaplastic large cell lymphoma, null type with aberrant expression of PAX5 and CD138: A diagnostic
Muhammad Atif Salyana1, Shahbaz Khan1, Xinmin Zhang1
1Department of Pathology and Laboratory Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA.
Abstract:
A 72-year-old man was found to have generalized lymphadenopathy, splenomegaly, and elevated serum lactate dehydrogenase. Fine-needle aspiration and core needle biopsy of a cervical lymph node revealed a large lymphoid cell proliferation with features suggestive of anaplastic large cell lymphoma (ALCL). However, immunophenotypically, the neoplastic cells expressed PAX5 and CD138 in addition to CD30, CD45, MUM-1 and were negative for T-cell markers, B-cell markers, CD15, ALK-1, HHV-8, EBER, kappa, lambda, and pancytokeratin. The ambiguous phenotype triggered further workup. Subsequent molecular studies demonstrated T-cell receptor gene rearrangement and lack of immunoglobulin gene rearrangement. Based on these findings, a diagnosis of ALK-negative ALCL, null type with aberrant expression of PAX5 and CD138, was rendered. The patient received palliative care due to his poor condition and died of the disease. This case presents a diagnostic pitfall and highlights the importance of cytological evaluation and complete workup in the diagnosis of unconventional lymphomas.
