Pleural mesothelioma with initial presentation as cervical lymphadenopathy.

A 41-year-old woman presented with a left neck mass. Light microscopy suggested metastatic large cell carcinoma, but subsequent electron microscopy demonstrated typical epithelial mesothelioma. Initial clinical investigations were negative and the primary pleural tumor remained inapparent for a further 8 months. The woman ultimately died from the effects of superior vena caval obstruction. Mesotheliomas frequently metastasize late in the course of the disease, but it is exceptional for them to present as a metastatic tumor of unknown primary origin.