[A case of squamous cell carcinoma of the lung associated with acanthosis nigricans and solitary bronchial papilloma].

A 58-year-old man diagnosed as having acanthosis nigricans symmetrically distributed on the face, neck, hands, navel and external genitals, was admitted to our department for further investigation of abnormal chest films. Bronchoscopy revealed squamous cell carcinoma of left S6 and solitary bronchial papilloma of left S3. After left pneumonectomy, facial hyperpigmentation improved slightly. About half of the reported cases of acanthosis nigricans are accompanied by various kinds of malignant neoplasms, mostly adenocarcinomas of the digestive system. The association with squamous cell carcinoma of the lung in our case appears to be unique. Only 16 cases of solitary bronchial papilloma, including our case which had the smallest diameter of 2 mm, have been reported in Japan. While it is suggested that malignant neoplasms contribute to abnormal epidermal growth such as acanthosis nigricans, a causal relationship between squamous cell carcinoma of the lung and bronchial papilloma cannot be established.