BACKGROUND: Pellagra is a rare clinical syndrome caused by niacin deficiency, and although most commonly nutritional in origin, may be secondary to carcinoid syndrome.
CASE: A premenopausal nulliparous woman with metastatic carcinoid tumor developed isolated vulvovaginal manifestations characterized by well-demarcated symmetrical vulvar erythema, mild scaling, ulcerations, and dyspareunia. Tryptophan levels were low. Treatment with nicotinamide resulted in dramatic improvement; however, after 2 years of effective treatment, she developed lichen sclerosus.
CONCLUSION: Patients with carcinoid tumor presenting chronic vulvar lesions should be evaluated for pellagra. Subsequent development of lichen sclerosus at the site of vulvar dermatosis may be a feature of the “Koebner phenomenon,” which describes appearance of lichen sclerosus in scarred areas or sites prone to friction.