Aggressive digital papillary adenocarcinoma on the palm with pulmonary metastases.

A 41-year-old Japanese male had aggressive digital papillary adenocarcinoma with pulmonary metastases. He had an asymptomatic, solitary, dome-shaped, skin-colored firm nodule on his left palm for half year. The tumor consisted of multiple lobules of anaplastic epithelial cells with central necrosis. The neoplastic cells were immunohistochemically positive for cytokeratin and S-100 protein. Two years after the lesion was removed, pulmonary nodular lesions were found on chest X-ray. On histopathological examination, the pulmonary biopsy specimens showed lobular proliferation of acantholytic tumor cells and some ductal structures associated with papillary projections. Five years after the initial removal of the lesion, the patient was referred to our hospital because of a recurrent skin nodule on his left palm. The recurrent skin tumor was found to have lobular proliferation of anaplastic cells. On immunohistochemistry, the pulmonary metastasis and the palmar skin nodules were identical. The tumor was diagnosed as an aggressive digital papillary adenocarcinoma. This report is a rare case of aggressive digital papillary adenocarcinoma that was diagnosed based on the histopathology of the pulmonary metastases, which showed ductal structures associated with papillary projections.