A 59-year-old man with a history of renal failure requiring a kidney transplant presented with an enlarging lesion on his chest. A biopsy specimen of the lesion was consistent with trichilemmal carcinoma. The lesion was treated with Mohs’ micrographic surgery. To our knowledge, this is the first reported case of trichilemmal carcinoma occurring in a renal transplant patient. Trichilemmal carcinoma (TLC) is a rare cutaneous carcinoma that usually appears as a solitary lesion in individuals after the fifth decade. It generally presents on sun-exposed skin, including the face and arms. However, it can appear as multiple lesions on non–sun-exposed skin. A 59-year-old white man presented to the dermatology department on 27 August 1997 with a 1- to 2-year history of a gradually enlarging mid-chest lesion (Fig. 1). His medical history was significant for a long history of hypertension, glaucoma, and cataracts. He received a kidney transplant in 1992, and his medications included prednisone, azathioprine, and cyclosporine A. His examination revealed a hyperkeratotic papulonodular lesion. A biopsy specimen of his chest lesion was consistent with a TLC. The histologic examination demonstrated a broad platelike proliferation of the epidermis. Numerous lobules with clear cells and mitotic figures were noted in the center of the lobules. Peripheral palisading of the nuclei and a hyaline mantle were noted around the lobules. The TLC was excised with Mohs’ micrographic surgery. The patient has had no recurrence in 6 years. Figure 1: Hyperkeratotic papulonodular trichilemmal carcinoma on the mid chest.TLC is a rare cutaneous tumor arising from the external root sheath of the hair follicle and is thought to be the malignant counterpart of trichilemmoma (1). Clinically, the tumor usually presents as a solitary lesion on sun-exposed skin, and the appearance ranges from a flesh-colored telangiectatic plaque or papule to a hyperkeratotic or ulcerated crater (2,3). Microscopically, TLC exhibits lobular proliferation or infiltration that may be centered on a pilosebaceous unit. The tumor is composed of glycogen-rich clear cells that are diastase-positive (2). The tumor may exhibit intraepithelial or pagetoid spread or may invade the dermis. TLC may also have a plasma cell or lymphocytic infiltrate. All reports of TLC have been in immunocompetent patients. One report exists of multiple TLC presenting in a patient with a history of pulmonary tuberculosis requiring subsequent partial pneumonectomy. The patient received approximately 50 to 60 chest radiographs over a 30-year period. The authors postulated that the x-ray exposure may have contributed to the development of multiple TLC in the non–sun-exposed area. One of the eight cases presented by Reis et al. (4) had a history of xeroderma pigmentosum. It is well documented that transplant patients have an increased risk of developing cutaneous skin cancers in addition to lymphomas and solid organ malignancies (4). Cutaneous malignancies are the most common cancers that develop in renal allograft patients (4,5). The most common skin cancer in the patient population is squamous cell carcinoma (SCC) followed by basal cell carcinoma (BCC). SCC has a higher incidence than BCC in the transplant population, with a ratio ranging from of 5:1 to 20:1. This contrasts with the ratio in the normal population, where the reverse is true. In addition to SCC and BCC, Merkel cell carcinomas, melanomas, Bowen’s disease, Kaposi sarcoma, and others have been diagnosed in renal transplant patients (4). However, to our knowledge, there has been no previous report of a TLC appearing in a renal transplant patient. Algin B. Garrett Kimberly A. Scott