Fine-needle aspiration cytology of type A thymoma with adenoid cystic pattern: a case report with emphasis on peculiar hyaline globules in cytologic smear.

Here we report a case of type A thymoma with adenoid cystic pattern, which extended to the lower anterior neck and clinically mimicked a nontoxic thyroid goiter. The cytologic smears of fine-needle aspiration showed cohesive fragments of short spindle cells with finely granular chromatin and inconspicuous nucleoli. Scant interspersed lymphocytes were present. On air-dried Liu stained preparation, there were many magenta-colored hyaline globules wrapped by spindle tumor cells. The cytomorphologic findings correlated with the adenoid cystic pattern in histology. The cytologic differential diagnosis and the prognostic aspects of type A thymoma were briefly discussed.