Endocrine Abstracts

Objective: To assess the prevalence of multiple endocrine neoplasia type 1 (MEN1) in patients with symptomatic primary hyperparathyroidism (PHPT).

Methods: A retrospective analysis of 75 consecutive patients with symptomatic PHPT from January 1994 to July 2012 was done, who underwent parathyroid surgery at our centre. Five patients had MEN1 syndrome. Among them 1 was familial MEN1. The patients with MEN1 were analyzed based on clinical presentation, biochemical and hormonal profile, imaging modalities and treatment outcome.

Results: Mean age of the study patients was 28.6±12.9 years (male:female=4:1). Mean age of the rest all patients was 43.5±11.5 years. Four were symptomatic at presentation and one was diagnosed on family screening. Mean duration of symptoms was 23.8±12.1 months. Bone pains and painful proximal myopathy were the commonest presentation (4/4), followed by pathological fractures in one case. Distal renal tubular acidosis was diagnosed in one case, which normalized after surgery. The most common presenting manifestation was PHPT in four patients (80%), followed by hyperprolactinemia due to pituitary tumor in one patient (20%). PHPT was a universal feature (100%) in all MEN1 syndrome followed by pituitary tumors in three cases (60%) and enteropancreatic neuroendocrine tumors in two cases (40%), with both being insulinoma. Among the pituitary tumors, prolactinoma and nonfunctioning pituitary adenoma were present in two each cases demonstrating equal prevalence.

All PHPT patients underwent parathyroidectomy and the ones with MEN1 had mean parathyroid gland weight was 1235.6±684.5 mg, which was larger than the rest (mean parathyroid gland weight was 835.4±178.5 mg, P=0.04). Three PHPT patients with MEN1 syndrome had double adenoma and two patients had multiglandular parathyroid involvement.

Discussion: PHPT patients with MEN1 tend to be younger with multifocal involvement and larger glands. Eighty % of MEN cases had PHPT as initial manifestation followed by hyperprolactinemia in 20% cases. Our series demonstrated higher incidence of symptomatic PHPT, higher prevalence of pituitary tumors (80%) and insulinoma (40%). Additionally prevalence of pituitary involvement (80%) outscores the prevalence of enteropancreatic neuroendocrine tumors (40%). These deviations from classic involvement depicted in literature could be due to small sample size of the study population.

Conclusion: All young patients with double adenoma or multiglandular parathyroid involvement should be screened for MEN1 syndrome irrespective of the symptoms. To avoid the recurrent surgical procedure, high index of suspicion is needed for diagnosis.