Scalp porocarcinoma and lichen planopilaris

Porocarcinoma (PC) is a malignant neoplasm arising from the intraepidermal ductal portion of the sweat gland duct. Lichen planopilaris (LPP) is a not so rare variant of cutaneous lichen planus (LP) with a preferential involvement of hair follicles, consisting of a chronic lymphocytic inflammation, leading to cicatricial alopecia. A 42-year-old woman, recently diagnosed with HIV infection, was referred to our clinic because of an alopecic patch of 6 years' duration. In the upper region of the alopecia a 1.5cm nodule was noticed, which the patient stated had started growing soon after the appearance of the hair loss. Biopsy of the alopecia margin confirmed the diagnosis of LPP, whereas biopsy of the nodule revealed an infiltrating tumor consistent with the diagnosis of PC. We present a scalp PC emerging in a background of LPP in an HIV patient. We do not know the role, if any, HIV infection and LPP played in this particular case. Immunosuppression and HIV have been implicated in the etiology of PC. However, her HIV diagnosis was made after the appearance of the scalp nodule. We did not find any association between LPP and PC in the literature. Even though an association by chance cannot be excluded, this deserves further investigation.