A Paradigm Shift in Renal Cell Carcinoma: Recognizing Hypoglycaemia as a Significant Paraneoplastic Syndrome

Recurrent hypoglycaemia is a rare paraneoplastic syndrome associated with several cancers, including renal cell carcinoma (RCC). Here we present a curious case of a patient with type 2 diabetes mellitus (T2DM) who had numerous hospitalisations due to recurrent hypoglycaemia. A well-defined lesion at the lower pole of the right kidney and bilateral pyelonephritis were found during imaging investigations. A biopsy from the lesion confirmed clear cell carcinoma of the kidney and the most probable cause of recurrent hypoglycemia was paraneoplastic syndrome related to RCC. Analysis of Insulin-like growth factor levels revealed that recurrent hypoglycaemia might be the result of non-islet cell tumor-hypoglycaemia (NICTH). This case emphasizes how crucial it is to rule out paraneoplastic syndromes like NICTH in individuals presenting with hypoglycaemia that cannot be explained, even when pre-existing diabetes is present. Furthermore, this study emphasizes the need to include RCC in the differential diagnosis.