Metastatic renal clear cell carcinoma mimicking stage IV lung cancer.

We present a 63-year-old man who was investigated for a lesion in the apex of the left lung and a coexisting osteolytic lesion in the right major trochanter. FNA of the thoracic mass was suggestive for malignancy yet not diagnostic regarding the tumor type and the site of the primary tumor. A diagnosis of a stage IV lung cancer was favored and he underwent a left exploratory thoracotomy in view to resect the primary tumor. An extrapulmonary mass localized to the pleura not involving the ipsilateral lung was disclosed. Multiple biopsies revealed metastatic clear cell RCC. A 5 x 7 cm left renal tumor was revealed in a postoperative abdominal CT scan. He was treated with combination of interferon A and vinblastin followed by radical nephrectomy. Twenty-four months after the diagnosis he is alive without evidence of local or distant recurrence. Pleural metastases from RCC are mainly presented as malignant pleural effusions. Thoracic metastatic lesions localized to the pleura, forming solitary or multiple mass(es) have been rarely reported. We review the literature regarding this rare clinical manifestation of the disease and we discuss diagnostic and therapeutic options.