Metastatic bone disease from an occult renal primary

We report a rare presentation of metastatic renal cell carcinoma (RCC) in a 71-year-old man who presented with persistent shoulder pain. MRI revealed widespread lytic lesions within the bones suggestive of metastatic disease but extensive imaging including CT chest, abdomen and pelvis with contrast and fluorodeoxyglucose-positron emission tomography did not identify a primary cancer. The diagnosis was ultimately made from a targeted bone and subsequently targeted liver biopsy, whereby immunohistochemistry was consistent with metastatic RCC (mRCC). While bone metastases in RCC are very common, it is extremely rare for patients to present with mRCC and no identifiable renal primary.