A case of anaplastic lymphoma kinase-positive large B-cell lymphoma: aspiration cytology findings.

Anaplastic lymphoma kinase-positive (ALK+) large B-cell lymphoma (LBCL) is a rare subtype of non-Hodgkin B-cell lymphoma that exhibits a more aggressive clinical course and poorer prognosis than the typical diffuse large B-cell lymphoma. In this study, we report the case of a 67-year-old man with left cervical lymph node swelling. Aspiration cytology revealed many clusters of cohesive, large, and solitary cells. The tumor cells had abundant cytoplasm and large round-to-oval nuclei with prominent nucleoli. The Giemsa staining specimens exhibited amorphous global bodies adjacent to some clusters. Histologically, large tumor cells occupied the lymph nodes in a sinusoidal pattern, and immunohistochemically, these cells were cytokeratin-, CD19(-), CD20(-), CD79a(-), CD3(-), CD30(-), CD138(+), IgG(-), IgA(+), and ALK(+). Chromogenic in situ hybridization revealed restricted immunoglobulin light-chain expression. Fluorescent in situ hybridization demonstrated translocation of the ALK gene. The tumor cells were negative for Epstein-Barr virus and human herpesvirus 8. It is important to differentiate ALK+LBCL from metastatic carcinoma and other lymphoma subtypes with similar histological features to ensure a proper treatment strategy and prediction of prognosis.