Lymphocyte-rich thymoma often contains lymphoblasts, and lymphoblastic
lymphoma often infiltrates the thymus gland. Although these two neopl
asms are clinically distinct in most cases, their cytologic features m
ay be similar on biopsy. We describe a fine-needle aspiration biopsy o
f a thymoma in a 50-yr-old man to increase awareness of this pitfall i
n cytologic interpretation. (C) 1996 Wiley-Liss, Inc.