Incomplete MEN in a Female

Abstract

Introduction: Symptomatic hypoglycemia without diabetes is unusual and prompts further evaluation including use of exogenous insulin or oral hypoglycemic agents and insulinoma. Insulinoma could present sporadically or as a part of syndrome; most commonly MEN (multiple endocrine neoplasia) 1or Wermer Syndrome. It is usually diagnosed at younger age but reported in elderly population on rare occasions. We present an old female presenting with hypoglycemia and found to have incomplete MEN 1 syndrome. Case: A 72 year old female was brought to hospital by EMS after being found unconscious at home. Her initial blood glucose was 22 when checked by EMS with transient improvement after giving dextrose 50%. In the emergency room, again she was noted to have blood glucose 33 and started on D5-normal saline infusion. Her past medical history included chronic kidney disease, hypertension, and stroke with residual right hemiplegia. Initial physical exam was significant for elevated BP: 220/118, slurred speech, altered mental sensorium, residual right arm and leg weakness. Laboratory values: Ca 11 mg/dl (corrected calcium 11.32), creatinine 2.07 mg/dl (baseline), Albumin 3.6 g/dl, Vitamin D 70 ng/ml, unremarkable CBC. Computed tomography (CT) of head was negative for intracranial abnormality. Patient met the criteria of Whipple's traid and further workup for hypoglycemia revealed elevated serum Insulin 33.4 U/IU/ml, Pro insulin 65.2 pmol/l, C Peptide 27.1 ng/ml, parathyroid hormone 147 pg/ml. The sulfonylurea screen was negative. MRI abdomen, endoscopic ultrasound and octreotide scan failed to show any obvious pancreatic lesion. Parathyroid scan revealed parathyroid adenoma in left lower neck. Due to patient's age and medical co-morbidities, decision was made for medical management with diazoxide and bisphosphonate with parathyroidectomy later on and genetic testing for family members. Discussion: Insulinoma, rare fascinating tumor is associated with MEN1 in less than 10% of cases. MEN 1 is autosomal dominant inheritance with 95% penetrance of gene by 50 years, but sporadic mutations occur and usually presents with hyperparathyroidism. Pancreatic islet cell tumors are the second most common presentation and can occur in 30-80% of MEN1 patients. Patients with MEN1 have decreased life expectancy and 70% of these patients die of causes directly related to MEN1 as reported by a multicenter trail. Our patient had incomplete expression of MEN 1 with only parathyroid adenoma and Insulinoma. It should be noted that these tumors could present in the elderly patients and one needs to look for these when dealing with elderly patients with hypoglycemia and other typical presentation of MEN1.