Abstract: This article reports a case of paraneoplastic acanthosis nigricans in a 57-year-old male patient who presented with verrucous hyperplasia and hyperpigmentation on the extremities, head and neck for 3 months. During the course of the disease, the patient also had symptoms such as numbness in both feet and dizziness. Dermatological physical examination revealed characteristic skin lesions including brownish-black hyperpigmentation, hyperkeratosis and verrucous hyperplasia in multiple parts. Laboratory tests showed an elevated carbohydrate antigen 72-4 (CA72-4). Gastroscopy, colonoscopy and pathological examinations confirmed poorly cohesive gastric carcinoma (signet ring cell type), and skin pathological examination was consistent with the manifestations of paraneoplastic acanthosis nigricans. Clinically, symptomatic treatments for skin lesions were administered with acitretin capsules, loratadine and other drugs, and the patient was advised to be referred to the Department of Gastrointestinal Surgery for further treatment of gastric carcinoma. This case suggests that clinicians shonld pay atlention to screening for associated malignant tumors in patients with acanthosis nigricans.

Key words: malignant acanthosis nigricans, gastric poorly cohesive carcinoma