Fine‐needle aspiration diagnosis of squamous cell carcinoma in a lymph node involved with small lymphocytic lymphoma: Case report and review of the literature

Abstract

Diagnosis of two distinct malignant entities existing concurrently and at the same location (synchronous malignancy) by fine- needle aspiration (FNA) is unusual but may occur. Small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) in particular is associated with an increased incidence of secondary tumor, likely due to associated immunodeficiency. Co-occurrence of some carcinomas such as squamous cell carcinoma (SCC), may show especially aggressive behavior. A 57-year-old Caucasian male presented with recurrent upper extremity lymphedema and diffuse lymphadenopathy of the axillary and cervical regions. FNA of a large cervical lymph node was diagnostic for both atypical lymphocytic proliferation and SCC. Flow cytometric analysis showed the atypical lymphocytic proliferation to be positive for CD5, CD23, CD19, CD20, HLA-DR, CD38, and the population was kappa light chain restricted. These cells were negative for CD-10 and FMC-7 antigens, suggesting a phenotype of B-cell SLL/CLL. We report a rare occurrence of metastatic SCC to a lymph node infiltrated by SLL/CLL. The diagnosis was achieved by a combination of cytomorphologic examination of FNA smears, immunohistochemical staining of cell block material, and flow cytometry on the sample obtained by FNA. To the best of our knowledge, only three cases of SCC metastasis to SLL/CLL diagnosed by FNA have been reported in the English literature. Though rare, awareness of such a possibility and careful cytological examination under the appropriate clinical conditions is warranted.