A 52-year-old woman presents with a 3 cm lytic lesion in the trochanteric region of the femur. Biopsy shows nests of epithelial cells with clear cytoplasm. PET scan shows an avid right renal mass. This is MOST likely:

• A Primary osteosarcoma of the femur
• B Solitary plasmacytoma
• C Giant cell tumor with secondary degeneration
• D Metastatic renal cell carcinoma ✓

Explanation

Metastatic renal cell carcinoma (RCC) to bone classically presents as a lytic, highly vascular lesion with 'clear cell' morphology on biopsy — the clear cytoplasm reflects abundant intracytoplasmic glycogen and lipid. RCC is one of the common primary tumors causing solitary bone metastases (mnemonic: Kidney, Lung, Breast, Thyroid, Prostate — 'Kidney Loves Bleeding Thus Profusely'). The concurrent renal mass on PET confirms RCC as primary. Surgical intervention for metastatic RCC to bone often includes preoperative embolization due to high vascularity risk of intraoperative hemorrhage.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.