A 74-year-old woman with no history of trauma visited our hospital with right-sided abdominal pain and general malaise. Blood tests revealed elevated inflammatory markers. A computed tomography (CT) scan revealed a 8 cm mass and subcapsular hematoma on the lower pole side of the right kidney. She was diagnosed with a malignant tumor or renal abscess combined with subcapsular hematoma and inflammation and was treated conservatively with antibiotics. The symptoms quickly improved. Although kidney biopsy was performed, no obvious malignant cells were found. Since a subsequent CT scan could not exclude the possibility of kidney cancer, radical nephrectomy was performed. The histopathological diagnosis was clear cell renal cell carcinoma. She has not experienced recurrence within 10 months after the surgery. Clear cell renal cell carcinoma combined with subcapsular blood is relatively uncommon and can be difficult to diagnose, requiring careful decision-making regarding treatment indications.