Importance of Individual Ghost Cells in Fine-Needle Aspiration Cytology Diagnosis of Pilomatricoma.

Background: Although histological diagnosis of pilomatricoma is not difficult because of its unique histological features, cytological diagnosis through fine-needle aspiration cytology (FNAC) is often problematic due to misdiagnoses as malignancy. Methods: We reviewed the cytological features of 14 cases of histologically-proven pilomatricoma from Korea Cancer Center Hospital, with a discussion on the diagnostic pitfalls of FNAC. Results: Among 14 cases of pilomatricoma, 10 (71.4%) were correctly diagnosed through FNAC, and two (14.3%) were misdiagnosed as carcinoma. Cytologically, all cases had easily recognizable clusters of basaloid cells and foreign body-type multinucleated cells. Although ghost cells were also found in all cases, some were inconspicuous and hardly recognizable due to their small numbers. Conclusions: An accurate diagnosis of pilomatricoma in FNAC is feasible with consideration of clinical information and close examination of ghost cells.