Primary squamous cell carcinoma of the kidney parenchyma with ascending colon invasion: A case report and literature review

INTRODUCTION: Primary squamous cell carcinoma (SCC) of the kidney parenchyma is extremely rare, with only seven cases reported to date. Herein, we present a case of primary with colon invasion. PRESENTATION OF CASE: A 61-year-old man presented right flank pain for 5 months. Computed tomography (CT) showed multiple renal stones and a necrotic mass in the lower pole of the right kidney, which was suspicious for ascending colon invasion. There was no history of radiation or occupational exposure to chemicals. Radical nephrectomy, right hemicolectomy, and lymph node dissection were performed. The kidneys showed a solid mass with multiple renal stones. The tumor comprised nests of atypical squamous cells and keratin pearls; however, the renal pelvis was normal. 18-Fluorodeoxyglucose-positron emission tomography/CT failed to demonstrate other primary site. Therefore, the patient was diagnosed as primary SCC of the kidney. The patient did not receive adjuvant therapy and was alive during follow-up for 6 months after surgery. DISCUSSION: SCC of the urinary tract is considered to be the result of squamous metaplasia of the urothelium, which may potentially progress to SCC. Squamous metaplasia may be caused by chronic irritation. However, the mechanism of SCC remains unclear. Although the prognosis of SCC is similar to that of urothelial carcinoma when compared stage for stage, SCC tends to be diagnosed at a more advanced stage. CONCLUSION: This is a rare case of kidney SCC with adjacent organ invasion. Additional studies are required to further our understanding of this rare tumor and improve diagnosis and treatment.