A MEN1 syndrome with a paraganglioma

Abstract

Germline mutations of the MEN1 gene cause multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disorder characterized by tumors of the parathyroids, the pancreas, and the anterior pituitary. Paraganglioma (PGL) is a rare endocrine tumor, which can be sporadic or genetically determined. To date, PGL has never been reported as a feature of MEN1.We report here a patient presenting three features of MEN1 syndrome (hyperparathyroidism, pancreatic neuroendocrine tumor, and adrenocortical adenoma) associated with PGL. Genetic analysis of MEN1 gene revealed a new missense mutation in exon 5 (AGGAAG), causing the substitution of arginine by lysine at codon 275. Screening for other genetic disorders (SDHx, TMEM127, MAX, CDKN1B) causing PGL was negative. Immunohistochemical analyses showed normal levels of succinate dehydrogenase (SDH)A and SDHB in the PGL. The proband's sister, bearing the mutation, had primary hyperparathyroidism. It was the first typical MEN1 syndrome reported with an extra-adrenal PGL.

Figure 1

Pedigree of the kindred. The arrow indicates the proband. Squares represent male family members, circles female family members, and slashes deceased family members; dark symbols denote symptomatic carriers of the MEN1 gene mutation, gray asymptomatic carriers, and blank non-carriers. Note: members I-1 and I-2 were not tested; the question mark represents a clinical presumption for the presence of the mutation.

Figure 2

SDHA and SDHB immunohistochemistry in the patient's PGL. Normal SDHA and SDHB mitochondrial staining was observed in tumor cells. Scale bar=50 μm.