[Proliferating trichilemmal cyst with focal segments of metastatic squamous epithelial carcinoma].

A large ulcerated tumor covered the right hemisphere of the scalp of a 77 year old woman. By histological, immunohistological, and electronmicroscopical examination, a proliferating trichilemmal cyst with focal areas of a poorly differentiated squamous cell carcinoma was identified. Six months after extirpation of the entire tumor and dissection of supraomohyoidal lymph nodes, metastases in nuchal and supraclavicular lymph nodes and soft tissue of the neck became apparent. The present case underlines the necessity of a preoperative diagnostic evaluation and of radical surgical treatment for proliferating trichilemmal cysts.