Acanthosis nigricans in a patient with lung cancer: a case report.

Some skin lesions may accompany malignancies. Acanthosis nigricans, one such lesion, is a paraneoplastic dermatosis characterized by hyperpigmented and velvety verrucose plaques observed as symetric eruptions. With this report, we aim to present a rare case of concomitant lung cancer and acanthosis nigricans. Malignant acanthosis nigricans is most commonly associated with intra-abdominal malignancies. A 65-year-old patient who had hyperpigmented, hypertrophic and symmetric verrucose lesions at the flexor surfaces of the lower and upper extremities, face, palms and the axillary region. Thoracic computed tomography demonstrated a hypodense mass lesion with a dimension of 5 x 5.5 cm at the center of basal segment bronchi of the left pulmonary lobe. Fiberoptic bronchoscopy showed that the access to the lower left lobe was almost completely obstructed by the endobronchial lesion. The result of the histopathologic examination of the endobronchial tissue biopsy was reported as non-small cell (adenocarcinoma) lung cancer. Result of the histopathologic analysis of the punch biopsy of the skin lesions was reported as acanthosis nigricans .There are no pathognomonic dermatological findings for lung cancer. In conclusion, there are skin lesions that accompany lung cancer and we believe that these should be considered for differential diagnosis.