Apocrine Sweat Gland Adenocarcinoma in the Left Retroauricular Area: A Rare Case Report

An 81-year-old woman without skin cancer history suddenly developed a left retroauricular soft, pink mass 2 years previously. The mass had slight exudation and a yellow scar on the surface, and it had rapidly increased in size fornearly past 1month. Itwasoriginally asymptomatic, but it showed intermittent ulceration during the disease course. Systematic physical examination revealed no other lesions in the axillae or anogenital region, which contain many apocrine cells, and no enlarged or otherwise abnormal regional lymph nodes. The patient’s medical history included facial nerve paralysis. Examination revealed a pink ridgy 3cm 4cm nodule with slight exudation and yellow scarring on the surface (Fig. 1). Early and capsid antibodies to Epstein–Barr virus were negative, and all tumor markers were normal, including carcinoembryonic antigen, carbohydrate antigen 125, carbohydrate antigen 199, carbohydrate antigen 153, a-fetoprotein, neuron-specific enolase, and human chorionic gonadotropin. The visceral examination at the