Multiple endocrine neoplasia type 2: An overview:

Perioperative temperature elevation: not all hyperthermia is malignant hyperthermia

OBJECTIVES

The objective of this review is to assist the readers, anesthesiologists, intensivists, and emergency physicians in making a more accurate diagnosis of perioperative fever or hyperthermia and subsequently choose the proper course of treatment.

AIM

To identify the many sources of perioperative fever and after a more accurate differential diagnosis, select appropriate treatment options. Most anesthesiologists, intensivists, and emergency physicians are not familiar with an expansive differential of perioperative fever. This article attempts to expose these physicians to that differential diagnosis.

BACKGROUND

Much of the medical literature has anecdotal reports, small case series, or limited reviews of the possible sources of hyperthermia or fever. This is especially true of the anesthesia literature.

RESULTS

A literature search was performed which identified many possible common and uncommon sources of fever. Some of these sources are quite relevant to the anesthesiologist. Other sources had potential relevance in obscure cases.

Classification and diagnostic criteria of variants of Hirschsprung's disease

"Variants of Hirschsprung's disease" are conditions that clinically resemble Hirschsprung's disease (HD), despite the presence of ganglion cells in rectal suction biopsies. The diagnosis and management of these patients can be challenging. Specific histological, immunohistochemical and electron microscopic investigations are required to characterize this heterogeneous group of functional bowel disorders. Variants of HD include intestinal neuronal dysplasia, intestinal ganglioneuromatosis, isolated hypoganglionosis, immature ganglia, absence of the argyrophil plexus, internal anal sphincter achalasia and congenital smooth muscle cell disorders such as megacystis microcolon intestinal hypoperistalsis syndrome. This review article systematically classifies variants of HD based on current diagnostic criteria with an additional focus on pathogenesis, epidemiology, clinical presentation, management and outcome.

Simultaneous presentation of giant pheochromocytoma, primary hyperparathyroidism, and mixed-medullary-papillary thyroid cancer in MEN 2A

The aim of this study was to describe a young man with probably the largest pheochromocytoma associated with MEN 2A, described till date. The patient, a non-vegetarian, fifth of eight siblings, married, having five children, presented with episodes of difficult-to-control hypertension requiring over five antihypertensives. He was referred to us with an abdominal CT scan that revealed a 16 cm left-sided adrenal mass. Biochemical testing confirmed a catecholamine secreting pathology. Histopathology confirmed the mass as a pheochromocytoma weighing 1.8 kg. Further evaluation suggested a parathormone-dependent hypercalcemia and a left-sided thyroid mass. Histopathology confirmed parathyroid hyperplasia and medullary carcinoma of the thyroid mixed with papillary carcinoma of thyroid. Putting all the findings together showed that the patient was suffering from multiple endocrine neoplasia 2. Multiple endocrine neoplasia 2A is a rare syndrome. The case is unique in the way it presented, with all the three tumors at the same time. The management was bold and addressed all the three lesions in the same hospital admission. We are also reporting the largest described case of pheochromocytoma from India.

Multiple endocrine neoplasia 2B: delayed presentation, rapid diagnosis

Multiple endocrine neoplasia (MEN) refers to the synchronous or metachronous development of tumours in two or more endocrine organs. MEN 2B is associated with medullary thyroid carcinoma and phaeochromocytoma along with classic morphological features such as marfanoid habitus and mucosal neuromas. Dominantly inherited germline mutations involving the REarranged during Transfection (RET) proto-oncogene are responsible. Affected patients usually present in childhood with thyroid mass or gastrointestinal symptoms. We describe the case of a 28-year-old man who presented to us with metastatic medullary thyroid carcinoma. He lacked the classic marfanoid habitus, but had mucosal neuromas and thickened corneal nerves. Whole-body metaiodobenzyl guanidine scan (MIBG) showed tracer uptake in adrenal and thyroid-confirming phaeochromocytoma and medullary thyroid carcinoma. This case exemplifies the late presentation of multiple endocrine neoplasia 2B and emphasises the need to screen all cases of medullary thyroid carcinoma for phaeochromocytoma.

New perspectives in the diagnosis and management of enteric neuropathies

Chronic disturbances of gastrointestinal function encompass a wide spectrum of clinical disorders that range from common conditions with mild-to-moderate symptoms to rare diseases characterized by a severe impairment of digestive function, including chronic pain, vomiting, bloating and severe constipation. Patients at the clinically severe end of the spectrum can have profound changes in gut transit and motility. In a subset of these patients, histopathological analyses have revealed abnormalities of the gut innervation, including the enteric nervous system, termed enteric neuropathies. This Review discusses advances in the diagnosis and management of the main clinical entities--achalasia, gastroparesis, intestinal pseudo-obstruction and chronic constipation--that result from enteric neuropathies, including both primary and secondary forms. We focus on the various evident neuropathologies (degenerative and inflammatory) of these disorders and, where possible, present the specific implications of histological diagnosis to contemporary treatment. This knowledge could enable the future development of novel targeted therapeutic approaches.

Molecular epidemiology of multiple endocrine neoplasia 2: implications for RET screening in the new millenium

OBJECTIVE

Twenty years ago, the groundbreaking discovery that rearranged during transfection (RET) mutations underlie multiple endocrine neoplasia 2 (MEN2) and familial medullary thyroid cancer (FMTC) ushered in the era of personalized medicine. MEN2-associated signs, taking time to manifest, can be subtle. This study sought to clarify to what extent conventional estimates of 1:200 000-500 000 underestimate the incidence of RET mutations in the population.

DESIGN

Included in this retrospective investigation were 333 RET carriers born between 1951 and 2000 and operated on at the largest German surgical referral center (286 carriers) or elsewhere (47 carriers).

METHODS

To estimate the incidence of RET mutations, the number of RET carriers born in Germany in five decades (1951-1960, 1961-1970, 1971-1980, 1981-1990, and 1991-2000) was divided by the corresponding number of German live births.

RESULTS

Owing to improved diagnosis and capture of FMTC and MEN2 patients, minimum incidence estimates increased over time: overall from 5.0 (1951-1960) to 9.9 (1991-2000) per million live births and year (P=0.008), and by American Thyroid Association/ATA class from 1.7 to 3.7 for ATA class C (P=0.008); from 1.8 to 2.7 for ATA class A (P=0.017); from 1.5 to 2.2 for ATA class B (P=0.20); and from 0 to 1.4 for ATA class D mutations per million live births and year (P=0.008). Based on 1991-2000 incidence estimates the prevalence in Germany is ∼1:80 000 inhabitants.

CONCLUSIONS

The molecular minimum incidence estimate of ≈1:100 000 was two- to fivefold greater than conventional estimates of 1:200 000-500 000.

2012 European thyroid association guidelines for genetic testing and its clinical consequences in medullary thyroid cancer

Twenty-five percent of medullary thyroid cancers (MTC) are familial and inherited as an autosomal dominant trait. Three different phenotypes can be distinguished: multiple endocrine neoplasia (MEN) types 2A and 2B, in which the MTC is associated with other endocrine neoplasias, and familial MTC (FMTC), which occurs in isolation. The discovery that germline RET oncogene activating mutations are associated with 95-98% of MEN 2/FMTC syndromes and the availability of genotyping to identify mutations in affected patients and their relatives has revolutionized the diagnostic and therapeutic strategies available for the management of these patients. All patients with MTC, both those with a positive familial history and those apparently sporadic, should be submitted to RET genetic screening. Once an RET mutation has been confirmed in an index patient, first-degree relatives should be screened rapidly to identify the 50% who inherited the mutation and are therefore at risk for development of MTC. Relatives in whom no RET mutation is identified can be reassured and discharged from further follow-up, whereas RET-positive subjects (i.e. gene carriers) must be investigated and a therapeutic strategy initiated. These guideline recommendations are derived from the most recent studies identifying phenotype-genotype correlations following the discovery of causative RET gene mutations in MEN 2 eighteen years ago. Three major points will be discussed: (a) identification of patients and relatives who should have genetic screening for RET mutations, (b) management of asymptomatic gene carriers, and (c) ethics.

Mechanisms of thyroid development and dysgenesis: an analysis based on developmental stages and concurrent embryonic anatomy

Thyroid dysgenesis is the most common cause of congenital hypothyroidism that affects 1 in 3000 newborns. Although a number of pathogenetic mutations in thyroid developmental genes have been identified, the molecular mechanism of disease is unknown in most cases. This chapter summarizes the current knowledge of normal thyroid development and puts the different developmental stages in perspective, from the time of foregut endoderm patterning to the final shaping of pharyngeal anatomy, for understanding how specific malformations may arise. At the cellular level, we will also discuss fate determination of follicular and C-cell progenitors and their subsequent embryonic growth, migration, and differentiation as the different thyroid primordia evolve and merge to establish the final size and shape of the gland.

Non-invasive prenatal diagnosis of multiple endocrine neoplasia type 2A using COLD-PCR combined with HRM genotyping analysis from maternal serum

The multiple endocrine neoplasia type 2A (MEN2A) is a monogenic disorder characterized by an autosomal dominant pattern of inheritance which is characterized by high risk of medullary thyroid carcinoma in all mutation carriers. Although this disorder is classified as a rare disease, the patients affected have a low life quality and a very expensive and continuous treatment. At present, MEN2A is diagnosed by gene sequencing after birth, thus trying to start an early treatment and by reduction of morbidity and mortality. We first evaluated the presence of MEN2A mutation (C634Y) in serum of 25 patients, previously diagnosed by sequencing in peripheral blood leucocytes, using HRM genotyping analysis. In a second step, we used a COLD-PCR approach followed by HRM genotyping analysis for non-invasive prenatal diagnosis of a pregnant woman carrying a fetus with a C634Y mutation. HRM analysis revealed differences in melting curve shapes that correlated with patients diagnosed for MEN2A by gene sequencing analysis with 100% accuracy. Moreover, the pregnant woman carrying the fetus with the C634Y mutation revealed a melting curve shape in agreement with the positive controls in the COLD-PCR study. The mutation was confirmed by sequencing of the COLD-PCR amplification product. In conclusion, we have established a HRM analysis in serum samples as a new primary diagnosis method suitable for the detection of C634Y mutations in MEN2A patients. Simultaneously, we have applied the increase of sensitivity of COLD-PCR assay approach combined with HRM analysis for the non-invasive prenatal diagnosis of C634Y fetal mutations using pregnant women serum.

Small intestinal ganglioneuromatosis in a dog

A 9-year-old female neutered collie-cross dog was presented with a 2-month history of persistent diarrhoea, weight loss and intermittent vomiting. Abdominal ultrasonography revealed one loop of jejunum with a markedly thickened and multifocally hyperechoic wall, without loss of wall layering. Laparotomies were performed for biopsy and resection of affected intestine. Histopathological examination revealed small intestinal ganglioneuromatosis (GN). The dog recovered well from surgery and the diarrhoea resolved. Eleven months later the dog has gained weight and remains asymptomatic. This is the first report of small intestinal GN affecting a mature dog, in which pathology was localized to the mucosal lamina propria and surgical treatment resulted in a successful outcome.

The genetics of phaeochromocytoma: using clinical features to guide genetic testing

Phaeochromocytoma is a rare, usually benign, tumour predominantly managed by endocrinologists. Over the last decade, major advances have been made in understanding the molecular genetic basis of adrenal and extra-adrenal phaeochromocytoma (also referred to as adrenal phaeochromocytoma (aPCA) and extra-adrenal functional paraganglioma (eFPGL)). In contrast to the previously held belief that only 10% of cases had a genetic component, currently about one-third of all aPCA/eFPGL cases are thought to be attributable to germline mutations in at least nine genes (NF1, RET, SDHA, SDHB, SDHC, SDHD, TMEM127, MAX and VHL). Recognition of inherited cases of aPCA/eFPGL is critical for optimal patient management. Thus, the identification of a germline mutation can predict risks of malignancy, recurrent disease, associated non-chromaffin tumours and risks to other family members. Mutation carriers should be offered specific surveillance programmes (according to the relevant gene). In this review, we will describe the genetics of aPCA/eFPGL and strategies for genetic testing.