Acanthosis nigricans maligna. Clinical and virological investigations

2 cases of acanthosis nigricans associated with an adenocarcinoma (signet ring cell carcinoma) of the stomach and a metastasizing small-cell carcinoma of unknown origin are reported. In both cases the skin lesions preceded the diagnosis of the carcinoma by months and acanthosis nigricans maligna was suspected by onset and localization of the dermatosis. There was no evidence of a papillomavirus etiology of the warty skin lesions. Virus particles could not be demonstrated either in ultrathin sections or in buffer extracts. Virus-specific DNA was not detectable after CsCL-ethidium bromide gradient centrifugation and cellular DNA did not hybridize under stringent or relaxed conditions with 32P-labelled human papillomavirus 6 or human papillomavirus 8 DNA.