Cytomorphologic examination of anaplastic large cell lymphoma by fine-needle aspiration cytology

BACKGROUND: The cytomorphology of anaplastic large cell lymphoma (ALCL) is distinctive yet variable. To the authors' knowledge, to date only small case series have described the cytologic findings noted in patients with ALCL. The current series is the largest case series presented to date to retrospectively review the cytomorpholgic findings noted in patients with ALCL, with specific attention paid to those with anaplastic lymphoma kinase (ALK)-negative ALCL. METHODS: Over a 13-year period, the available Diff-Quik cytology smears and surgical excision specimens taken from patients with ALCL were evaluated. Different clinical and morphologic parameters were evaluated, including ALK status. RESULTS: A total of 37 cases were retrieved and evaluated, 19 of which had both cytology and surgical pathology specimens available for review. ALK-negative ALCL cytology smears were found to have a high number of anaplastic cells compared with ALK-positive cases. The hallmark cells in the ALK-negative cases were not classic. CONCLUSIONS: ALCL can be diagnosed accurately by fine-needle aspiration cytology (FNAC) alone when aided by immunocytochemistry in ALK-positive cases. Ancillary studies should be anticipated such that material for cell block preparation and molecular studies is taken at the time of FNAC. The results of the current study demonstrate the varied FNAC morphology of ALCL. The presence of severe pleomorphism and anaplasia was found to correlate with ALK-negative status.