Mediastinal lymph node metastasis of renal cell carcinoma: A case report.

Renal cell carcinoma (RCC) may metastasize to mediastinal lymph nodes without any abdominal lymph node involvement. The present study describes an autopsy-proven case of RCC presenting with a large mediastinal mass; the case had been previously misdiagnosed as small cell lung carcinoma due to imaging analysis results, an elevated serum level of neuron-specific enolase and the presence of small atypical cells with a high nuclear/cytoplasmic ratio. Despite RCC occurrence being rare, it should be considered in the differential diagnosis, particularly when a mass located in the kidneys presents with metastases to the mediastinal lymph nodes, even if there is no involvement of the abdominal lymph nodes and the primary lesion is of a small size.