Primary renal parenchymal squamous cell carcinoma involving the renal pelvis: a case report and review of the literature.

Primary squamous cell carcinoma (SCC) of the renal parenchyma represents an exceptionally rare malignancy. We present an SCC case demonstrating renal pelvis invasion, histopathologically confirmed following radical nephrectomy. Postoperative adjuvant chemotherapy was initiated, with subsequent development of pulmonary and adrenal metastases at the 10th-month follow-up. After treatment adjustment, the patient is currently 12 months after the operation and is in good general condition. This case illustrates that a definitive diagnosis of primary renal parenchymal SCC remains achievable despite concomitant renal pelvis involvement, emphasizing the importance of comprehensive histopathological evaluation in such rare presentations.