Fine Needle Aspiration Cytology of Pilomatrixoma - A Report of Five Cases -

모기질종의 세침흡인 세포학적 소견 - 5예 보고 -

Pilomatrixoma is a benign tumor which usually occur as a solitary, firm nodule in the head and neck, and upper extremities of young people. This tumor is occasionally encountered during aspiration biopsy of subcutaneous masses, but only a small number of cases are correctly diagnosed prior to excision. We report five cases of pilomatrixoma. Four cases occurred in the neck and one case in the back. The characteristic fine needle aspiration cytologic features are shadow cells and basaloid cells in the background of inflammatory cells, including some multinucleated giant cells. The shadow cells were recognized in all five cases. These cells were pale, anucleated cells with relatively distinct cell borders. $May-Gr\ddot{u}nbald-Giemsa$ stain is useful for the identification of shadow cells. The recognition of shadow cells appears to be essential for accurate diagnosis of pilomatrixoma.