Clear Cell Renal Cell Carcinoma Recurrence Three Decades After Nephrectomy Presenting With New-Onset Diabetes

Clear cell renal cell carcinoma (ccRCC) is a common cancer that comprises the majority of all renal cancers. Patients typically present with hematuria, flank pain, and constitutional symptoms like fever, fatigue, and weight loss. ccRCC is often managed with chemotherapy, and, under some circumstances, the removal of a kidney. Although recurrence is possible following removal of the kidney, it is uncommon for a recurrence to occur after several decades. An 80-year-old man with a history of hypertension, hyperlipidemia, and ccRCC status post nephrectomy 33 years prior presented with two months of unintentional weight loss, fatigue, decreased appetite, and urinary frequency. Serial weights confirmed a 24-pound (12%) weight loss. Physical examination was notable only for mild epigastric tenderness. Laboratory evaluation demonstrated new-onset severe hyperglycemia with a hemoglobin A1C of 13.7% and serum glucose of 351 mg/dL, without prior documented diabetes. Given the rapid onset of hyperglycemia and significant weight loss, computed tomography imaging revealed a 9.2 × 6.4 cm pancreatic mass with additional lesions in the right lung and liver, initially concerning for metastatic pancreatic malignancy. Subsequent positron emission tomography and biopsy of the pancreatic head confirmed metastatic ccRCC. The patient was initiated on systemic therapy with axitinib and pembrolizumab, resulting in interval reduction of the pancreatic mass and resolution of pulmonary metastasis on follow-up imaging. Surgical excision of the pancreatic lesion has been scheduled in light of treatment response. This unique presentation and unlikely recurrence illustrate a rare case of ccRCC. Moreso, while diabetes is a known risk factor for ccRCC, the association between ccRCC and new-onset diabetes has rarely been documented. This case seeks to reinforce the importance of considering metastatic disease in patients with unexplained metabolic abnormalities and a remote history of renal cell carcinoma.