Malignant Pleural Effusion As the Initial Presentation of Renal Cell Carcinoma: A Case Report and Literature Review.

Renal cell carcinoma is the most common renal neoplasm. Its presentation is often very occult, and it may be discovered incidentally. It may present with the classic symptoms of back pain, flank pain, hematuria, or hypertension. Renal cell carcinoma may also present with malignant pleural effusion at diagnosis; however, it is very rare. In this case report and literature review, we describe a 77-year-old male who was diagnosed with renal cell carcinoma after presenting with a malignant pleural effusion - an extremely rare phenomenon. An analysis of the literature yielded 13 case reports, including ours, where the diagnostic presentation of renal cell carcinoma was a malignant pleural effusion. Our patient presented with left-sided chest pain. Imaging was suggestive of pleural effusion. CT and MRI imaging demonstrated masses in the upper and lower poles of the right kidney suggestive of renal cell carcinoma. CT imaging also showed lung nodules that were suggestive of pulmonary metastases. Biopsy and immunostaining of pleural tissue were positive for clear cell renal cell carcinoma. Therapeutic thoracentesis was performed. Despite this, the patient developed recurrent large-volume pleural effusions requiring drainage and placement of a pleural catheter. Our patient's extremely rare presentation of malignant pleural effusion as the diagnostic presentation of renal cell carcinoma along with recurrent, large-volume effusions requiring drainage has only been reported in the form of case reports in the literature.