Basal Cell Carcinoma Arising from a Follicular Hybrid Cyst

Malignant tumors arising from follicular cysts are rare. Herein, we report of a 62-year-old Japanese woman with a slowly growing tumor, 22 × 20 mm in size, located on her nose for 2 years. Histopathological examination of the surgically excised tumor showed that the tumor cells were basaloid and formed peripheral palisading patterns. The tumor contained a cystic structure in its center, and the cyst wall was lined with stratified epithelium with or without keratohyalin granules. Based on these findings, a diagnosis of basal cell carcinoma arising from a follicular hybrid cyst was made. To our knowledge, this is the first case of basal cell carcinoma originating from a follicular hybrid cyst. A review of previous reports of basal cell carcinoma from a follicular cyst indicated that the majority of previous cysts were located on the face, and that the lesions had been present for a relatively long time. The present case showed typical clinical findings and followed a regular course. Malignant transformation may be a rare event, but it can occur in a follicular cyst, so cysts and suspected cysts, especially those found on the face and those persisting for relatively long time, should always be subjected to histological examination.