Recurrent trichilemmal carcinoma with a large cutaneous horn formation

We describe an unusual case of trichilemmal carcinoma accompanied by a large horn formation in a 79-year-old man who presented with a brown tumor mass including a 15-cm-long horn on the vertex for one and a half years. Two months after the surgical removal of the primary tumor, the tumor recurred with a dimension 10×8×8 cm. The tumor was then excised again and the wound was covered using skin from the patient’s back. Microscopically, the tumor showed histology consistent with trichilemmal carcinoma. After 2 years, the patient had not shown any recurrence or metastases. We highlight the features that distinguish trichilemmal carcinoma from the other malignant tumors, such as squamous cell carcinoma, basal cell carcinoma, nodular melanoma, or keratoacanthoma.