[Recurrent hypoglycemia and a large intraabdominal tumor in a 61-year-old woman]

A 61-year-old woman was found unconscious by her husband. The emergency doctor detected hypoglycemia (blood glucose 1.7 mmol/l). This was the first such event, the patient had not been known to have diabetes mellitus. At admission the physical examination and the laboratory findings revealed no abnormalities.

A fasting test was aborted shortly after the start because of the onset of neurological symptoms. An insulinoma was excluded by detecting suppressed levels of insulin and C-peptide. Computed tomography of the abdomen revealed a mesenteric tumour of 9 cm in diameter, which was identified immunhistologically as a grade 1 follicular lymphoma (FL).  After exclusion of endocrinological causes the recurrent hypoglycaemia was diagnozed as part of a paraneoplastic syndrome associated with a non-islet cell tumour hypoglycaemia (NICTH) with a newly diagnosed FL.

Specific medication with the CD20 antibody rituximab (375 mg/m2, once per week for a total of four cycles) was initiated. There were no further episodes of hypoglycaemia. After one year the patient remains free of any symptoms.

After exclusion of any endocrinological reasons for hypoglycemia, differential diagnosis should include NICTH as paraneoplastic syndrome. In rare cases a hematological malignancy may be the underlying disease. The specific treatment of this disease likewise represents the causal treatment of NICTH.