MEN1 family with a novel frameshift mutation

Approach of Multiple Endocrine Neoplasia Type 1 (MEN1) Syndrome-Related Skin Tumors

Non-endocrine findings in patients with MEN1 (multiple endocrine neoplasia) syndrome also include skin lesions, especially tumor-type lesions. This is a narrative review of the English-language medical literature including original studies concerning MEN1 and dermatological issues (apart from dermatologic features of each endocrine tumor/neuroendocrine neoplasia), identified through a PubMed-based search (based on clinical relevance, with no timeline restriction or concern regarding the level of statistical significance). We identified 27 original studies involving clinical presentation of patients with MEN1 and cutaneous tumors; eight other original studies that also included the genetic background; and four additional original studies were included. The largest cohorts were from studies in Italy (N = 145 individuals), Spain (N = 90), the United States (N = 48 and N = 32), and Japan (N = 28). The age of patients varied from 18 to 76 years, with the majority of individuals in their forties. The most common cutaneous tumors are angiofibromas (AF), collagenomas (CG), and lipomas (L). Other lesions are atypical nevi, basocellular carcinoma, squamous cell carcinoma, acrochordons, papillomatosis confluens et reticularis, gingival papules, and cutaneous T-cell lymphoma of the eyelid. Non-tumor aspects are confetti-like hypopigmentation, café-au-lait macules, and gingival papules. MEN1 gene, respective menin involvement has also been found in melanomas, but the association with MEN1 remains debatable. Typically, cutaneous tumors (AF, CG, and L) are benign and are surgically treated only for cosmetic reasons. Some of them are reported as first presentation. Even though skin lesions are not pathognomonic, recognizing them plays an important role in early identification of MEN1 patients. Whether a subgroup of MEN1 subjects is prone to developing these types of cutaneous lesions and how they influence MEN1 evolution is still an open issue.

TIO Associated with Hyperparathyroidism: A Rarity, a Rule, or a Novel HPT-PMT Syndrome-A Case Study with Literature Review

Objective

Association of primary hyperparathyroidism (pHPT) with phosphaturic mesenchymal tumors (PMT) is rarely reported. This report entertains the hypothesis of the causal association of HPT with tumor-induced osteomalacia (TIO) and of the existence of HPT-PMT syndrome. Case Presentation. A 49-year-old man presented with fragility rib fractures, generalized bone pain, and muscle weakness worsening over the past 3 years. Initial tests demonstrated hypophosphatemia and high PTH. The diagnosis of pHPT was entertained, but parathyroid scan was negative. During a 2-year follow-up, the patient reported minimal improvement of symptoms after intermittent treatment with calcitriol and phosphate. Biochemical evaluation showed persistent hypophosphatemia with renal phosphate wasting, elevated FGF23, and osteopenia on DXA scan. TIO was suspected. Multiple MRIs and whole-body FDG-PET scans were inconclusive. The patient subsequently underwent ⁶⁸Ga-DOTATATE PET-CT, which revealed a somatostatin receptor-positive lesion in the lung. The resected mass was confirmed as PMT. The patient had dramatically improved symptoms, normal phosphate, calcium, and FGF23. During follow-up over 3 years postsurgery, the patient had slowly rising calcium and persistently elevated PTH.

Conclusion

The debate whether the patient had pHPT or tertiary HPT prompted literature review showing that aberrant genes including FGFR1, FGF1, fibronectin 1, and Klotho were mechanistically involved in the HPT-PMT association. This case highlights the pitfalls contributing to delayed diagnosis and treatment of TIO and hypothesizes the association between pHPT and PMT.

Multiple endocrine neoplasia type 1: analysis of germline MEN1 mutations in the Italian multicenter MEN1 patient database

PURPOSE

Multiple endocrine neoplasia type 1 (MEN1) is caused by germline inactivating mutations of the MEN1 gene. Currently, no direct genotype-phenotype correlation is identified. We aim to analyze MEN1 mutation site and features, and possible correlations between the mutation type and/or the affected menin functional domain and clinical presentation in patients from the Italian multicenter MEN1 database, one of the largest worldwide MEN1 mutation series published to date.

METHODS

The study included the analysis of MEN1 mutation profile in 410 MEN1 patients [370 familial cases from 123 different pedigrees (48 still asymptomatic at the time of this study) and 40 single cases].

RESULTS

We identified 99 different mutations: 41 frameshift [small intra-exon deletions (28) or insertions (13)], 13 nonsense, 26 missense and 11 splicing site mutations, 4 in-frame small deletions, and 4 intragenic large deletions spanning more than one exon. One family had two different inactivating MEN1 mutations on the same allele. Gastro-entero-pancreatic tumors resulted more frequent in patients with a nonsense mutation, and thoracic neuroendocrine tumors in individuals bearing a splicing-site mutation.

CONCLUSIONS

Our data regarding mutation type frequency and distribution are in accordance with previously published data: MEN1 mutations are scattered through the entire coding region, and truncating mutations are the most common in MEN1 syndrome. A specific direct correlation between MEN1 genotype and clinical phenotype was not found in all our families, and wide intra-familial clinical variability and variable disease penetrance were both confirmed, suggesting a role for modifying, still undetermined, factors, explaining the variable MEN1 tumorigenesis.

Combined biological therapy with lanreotide autogel and cabergoline in the treatment of MEN-1-related insulinomas

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome associated with the development of many endocrine tumors, involving mainly pituitary, parathyroids, pancreas, although a proliferative state interests all neuroendocrine system. MEN1 pancreatic neuroendocrine tumors (pNETs) are multiples and can secrete different hormones. The therapeutic approach is based on surgery which usually is followed by tumor relapse or persistence unless to be highly aggressive. Biotherapy with somatostatin analogs and dopamine agonists could be of great benefit to manage these patients without altering their life quality. We report a case of a 36-year-old MEN1 man affected with multicentric pNETs associated with insulinoma syndrome. Therapy with symptomatic agents (diazoxide), as well as biotherapy (lanreotide, cabergoline) was started. At 6-month follow-up, symptomatic agents were stopped and disease control was only based on lanreotide plus cabergoline. This combined biotherapy was able to control endocrine syndromes and tumor growth. Subsequently, a safer and selective surgical intervention on pNETs was performed. An excellent response to therapy with lanreotide autogel and cabergoline has been observed in a MEN1 patient with pNETs associated with insulinoma syndrome. The potential synergistic effects of lanreotide autogel and cabergoline on insulin-secreting neuroendocrine tumors are discussed.

Silent familial isolated pituitary adenomas: histopathological and clinical case report

Familial isolated pituitary adenoma (FIPA) is a rare condition independent of Carney Complex or MEN1. An international multicenter study recently described 28 nonfunctioning pituitary adenomas in 26 families with only two homogeneous nonsecreting phenotype families consistent of silent GH and silent gonadotroph adenomas, respectively. We present the clinical, genetic, and morphological analysis of two silent pituitary adenomas occurring in a man and his daughter, and discuss the differential diagnosis associated with their histological, immunohistochemical, and ultrastructural features. The patients developed invasive nonsecreting macroadenomas manifesting only with compressive symptoms. Genetic analysis in the father showed no MEN-1 germ-line mutation. Tissue samples obtained after paraseptal trans-sphenoidal surgery were studied by immunohistochemistry for adenohypophyseal hormones, low molecular weight cytokeratins (CAM 5.2), proliferation markers, and anterior pituitary transcription factors (Pit-1 and SF-1) and by electron microscopy for secretory granules. The clinical, histological, and immunohistochemical features of the lesions posed a differential diagnosis between a null cell adenoma and a silent corticotroph adenoma (Type II); on the basis of immunohistochemical stains for cytokeratin and adenohypophysis cell lineage markers, tumor behavior and ultrastructural studies we concluded for the second. The reported cases represent an as yet undescribed example of homogeneous family with silent corticotroph adenomas (Type II). Our observations support the trend for more aggressive behavior in nonsecreting FIPAs as compared with sporadic adenomas.