CYTOLOGIC CHARACTERISTICS OF A MALIGNANT PROLIFERATING TRICHILEMMAL CYST

The proliferating trichilemmal cyst (PTC)is a tumor that originates from hair follicles. It is almost always benign, but rare lesions have been reported with malignant potential. In the present case, the patient had a mass on the right side of her neck for a few years, which suddenly increased in size. Cytologic examination revealed many atypical squamous cells staining well with orange G and light green, suggestive of a squamous cell carcinoma. Total extirpation was performed under general anesthesia, gross pathology revealing a focally cystic tumor approximately 5 cm in diameter. The final diagnosis was malignant PTC from the characteristic features. We here report cytologic findings for this case with regional lymph node metastasis