Abstract
INTRODUCTION: Non-islet cell tumor hypoglycemia (NICTH) generally refers to hypoglycemia caused by tumors other than islet cell tumors. Although hypoglycemia is a common clinical emergency, NICTH rarely occurs in patients with breast cancer. PATIENT CONCERNS: A 47-year-old woman presented with repeated hypoglycemia hypoglycemia caused by a lobulated breast tumor. DIAGNOSES: Hypoglycemic symptoms occurred many times during fasting and in the early morning. Insulin and C-peptide levels were decreased; insulin-like growth factor (IGF)-II: IGF-I was greater than 10. Postoperative pathology revealed a lobulated tumor in the breast. After excluding other causes of hypoglycemia, the patient was diagnosed with NICTH due to breast cancer. INTERVENTIONS: Total mastectomy of right breast was performed. OUTCOMES: After 3 years of follow-up, hypoglycemia did not recur. CONCLUSION: Patients with breast cancer may experience recurrent hypoglycemia. After exclusion of insulinomatous and pancreatic origin of hypoglycemia, the possibility of NICTH should be considered, and surgical resection of the primary tumor should be performed as soon as possible.