Bronchial adenocarcinoid tumor metastatic to skin

A pulmonary neoplasm, evident initially as a metastatic nonpruritic skin rash in a 51-year-old man, progressed during a period of four months, leading to the patient's death. Histologic and histochemical studies of the skin metastasis, which were confirmed by transbronchial biopsy, demonstrated an adenocarcinoid tumor. Further ultrastructural studies of the skin metastasis showed that many tumor cells contained neurosecretory granules, although histochemical analyses had revealed the presence of only a few such tumor cells. Furthermore, in some cells both mucin and neurosecretory granules were present in the cytoplasm, confirming a previous observation in normal human segmental bronchi. These findings support the endodermal origin of such neoplasms.