Complete reversibility of paraneoplastic acanthosis nigricans after operation.

. A patient with widespread acanthosis nigricans is described. No abdominal tumour was found. Explorative thoracotomy disclosed numerous enlarged lymph glands containing squamous cell carcinoma. The left lung was removed but meticulous search did not disclose any tumour. The glands were removed as radically as possible. After the operation the skin improved and the lesions have disappeared completely. The observation time is over three years.