多発性脂腺嚢腫と脂肪腫を併発した Malignant proliferating trichilemmal tumorの1例

We report a case of malignant proliferating trichilemmal tumor associated with steatocystoma multiplex and lipoma on the scalp of a 71-year-old man who, against medical advice, refused follow-up treatment and examinations six months postoper-atively.On CT and MR images, an exophylic occipital mass lesion consisted of solid and cystic components with central calcification. An adjacent lipoma and multiple cystic lesions were seen subcutaneously.Suspected malignant tumors in the occipital region were totally resected with 3cm surgical margin and skin grafting was performed. The rest of the small isolated tumors were extirpated individually.Hisotopathlogical findings for the suspected malignant tumor revealed that it was composed of irregularly shaped, well circumscribed lobules of low grade malignancy of squamous epithelium in a palisaded pattern with typical trichilemmal keratiniza-tion. Other tumors were consistent with typical steatocystoma multiplex and lipoma. Because no regional lymph node metastasis had been seen, radical neck dissection was not performed.This case is a rare condition in that the patient with malignant proliferating trichilemmal tumor had typical steatocystoma multiplex not only on the scalp but also neck, chest, back and axillae symmetrically. We discuss the relationship between malignant proliferating trichilemmal tumor and steatocystoma multiplex and the differential diagnosis of Gardner syndrome.