Multiple Endocrine Neoplasia Type 2B: Early Diagnosis by Multiple Mucosal Neuroma and Its DNA Analysis

CRISPR-Based Precision Molecular Diagnostics for Disease Detection and Surveillance

Sensitive, rapid, and portable molecular diagnostics is the future of disease surveillance, containment, and therapy. The recent SARS-CoV-2 pandemic has reminded us of the vulnerability of lives from ever-evolving pathogens. At the same time, it has provided opportunities to bridge the gap by translating basic molecular biology into therapeutic tools. One such molecular biology technique is CRISPR (clustered regularly interspaced short palindromic repeat) which has revolutionized the field of molecular diagnostics at the need of the hour. The use of CRISPR-Cas systems has been widespread in biology research due to the ease of performing genetic manipulations. In 2012, CRISPR-Cas systems were, for the first time, shown to be reprogrammable, i.e., capable of performing sequence-specific gene editing. This discovery catapulted the field of CRISPR-Cas research and opened many unexplored avenues in the field of gene editing, from basic research to therapeutics. One such field that benefitted greatly from this discovery was molecular diagnostics, as using CRISPR-Cas technologies enabled existing diagnostic methods to become more sensitive, accurate, and portable, a necessity in disease control. This Review aims to capture some of the trajectories and advances made in this arena and provides a comprehensive understanding of the methods and their potential use as point-of-care diagnostics.

Dermatologic manifestations of thyroid disease: a literature review

Introduction

Thyroid hormone is considered one of the key regulatory hormones for skin homeostasis. Multiple organs are affected by the release of peripheral thyroid hormones (T4 and T3) further regulating various functions at a cellular level. Specifically, skin is considered an important target organ in which the thyroid hormone has a significant impact. Multiple skin diseases are associated with thyroid hormone dysregulation. However, other striking dermatologic manifestations are seen in nails and hair as well. Hypothyroidism, hyperthyroidism, and thyroid cancer can have an array of cutaneous manifestations, and we present the recent updates in this field.

Methods

A PubMed search was performed for updates in any new skin disease findings and treatments between 2010 and 2022. Research published in the past decade and previously known foundational skin findings associated with thyroid disease were presented in this review.

Conclusion

Cutaneous manifestations of thyroid disease is one of the first notable signs of thyroid hormone dysregulation. This article reviews the recent updates on the thyroid and skin interplay, and it further discusses overt visible findings and various available treatment modalities.

Subgemmal neurogenous plaques of the tongue: a systematic autopsy study

Subgemmal neurogenous plaque (SNP) is a subepithelial nerve plexus associated with taste buds, occasionally observed in tongue biopsies. There is no evaluation of the prevalence of this structure in the general population. We present a systematic study of samples obtained at random from the dorsal portion of the oral tongue in 205 consecutive complete autopsies. Each sample was about 15 mm long and 10 mm thick. Four hundred fifty-eight samples were routinely obtained and an average of 2.23±0.88 samples per case (range 1-7) was collected. The total number of SNPs observed was 556, with a mean of 2.71±2.68 per case (range 0-16). This means that for every 15 linear mm of the oral tongue, approximately 2.7 SNPs can be present. SNPs display several ages, and they do not show sex differences. The mean size of these structures was 2.1±0.94 mm (range 0.6-3.6 mm). SNP is characterized by its unique neural, zonal pattern with a superficial neurofibroma-like area and a deeper neuroma-like area. Special features of the SNPs include the presence of taste buds (49.1%), ganglion cells (26.3%), dilated thin-walled vessels (11.3%), salivary gland excretory ducts emptying on the surface of the papillae (6.1%), moderate-severe inflammatory infiltrate (6.8%), presence of lymphoid tissue in the vicinity (7.0%), and hyperplasia of the epithelial cover with pseudoepitheliomatous appearance (7.0%). The differential diagnoses include schwannoma, neurofibroma, ganglioneuroma, traumatic neuroma, mucosal neuroma, and squamous cell carcinoma. SNPs are small, normal structures that may undergo hyperplasia and are usually seen incidentally.

Dermatologic Manifestations of Endocrine Disorders

Endocrine disorders are known to involve all organ systems of the body, including the skin. The cutaneous manifestations of endocrine disorders can range from common findings such as acanthosis nigricans, pretibial myxedema, acne, hirsutism, hyper or hypopigmentation to rare cutaneous findings such as miliaria rubra, calciphylaxis, lentigines, and calcinosis cutis. These cutaneous symptoms can sometimes be the presenting symptoms or can even be pathognomonic of the underlying endocrine condition. In some cases, the cutaneous symptoms from an underlying endocrine abnormality may be the most prominent. These symptoms can significantly affect the quality of life of individuals. Often, individuals may seek health care from a dermatologist or primary care physician for isolated skin symptoms. Therefore, it is imperative for physicians to recognize the skin symptoms as the manifestation of the endocrine disorder for prompt diagnosis and treatment of the underlying endocrine disorder.

The Skin in Cowden Syndrome

Cowden syndrome (CS) is an autosomal dominant condition caused by mutations in the phosphatase and tensin homolog (PTEN) gene, and is characterized by multiple hamartomas and a predisposition to malignant tumors. Characteristic skin lesions include trichilemmomas, acral keratosis, mucocutaneous neuromas, oral papillomas, and penile macules, and are often the first clues to the underlying diagnosis. Here, we discuss the mucocutaneous manifestations of CS, differential diagnoses of genetic causes of each cutaneous finding, genetic analyses for patients with skin manifestations, management of patients with CS, and potential new targeted therapies for CS.

Genodermatoses with malignant potential

The hereditary nature of some forms of cancer was recognized long ago. Over time, recognition of associated findings led to the delineation of numerous hereditary cancer syndromes. Many of these syndromes also have cutaneous manifestations, the recognition of which can lead to their early identification. Recognition of these syndromes allows vigilant surveillance and preemptive treatment, which can dramatically impact the risks of morbidity and mortality for affected patients. The rise of rapid and accurate genetic testing now allows the early identification of asymptomatic at risk family members so that monitoring can be initiated as early as possible. The dermatologist plays a critical role in early identification of these syndromes and, in many cases, their treatment. This review summarizes many known hereditary cancer syndromes with cutaneous findings, their etiology, identification, evaluation, and management. Importantly, this is an ever evolving topic and new findings and syndromes will continue to be recognized. The dermatologist must be always alert to ensure they are detected.

Demographic, Clinical and Histopathological Features of Oral Neural Neoplasms: A Retrospective Study

Intraoral neural neoplasms though unusual may be clinically significant. The aim of this study was to categorize and evaluate oral neural tumors in a large oral pathology biopsy service. With IRB approval, a retrospective search of all neural neoplasms of the oral cavity in the archives of the University of Florida Oral Pathology Biopsy Service spanning from 1994 to 2015 was performed. Extraoral cases as well as cases with insufficient patient information were excluded. A total of 340 out of 164,578 submitted specimens in a 22 year period (0.2%) were included with a mean age of 43.3 years (range: 6-89), and 44% male and 56% female. The most commonly affected locations were: tongue (37.5%), palate (22%), lip (19%), and gingiva (14%). The microscopic diagnoses rendered, in descending order of frequency were: neurofibromas (NFs): 123 (36%), granular cell tumor (GCT): 108 (32%), schwannomas: 61 (17%), palisaded encapsulated neuromas: 39 (11%), benign neural lesion not otherwise specified: 8 (2%), and mucosal neuroma c/w multiple endocrine neoplasia type 2B (MEN 2B): 1 (< 0.5%). Six cases of NF reported a history of neurofibromatosis Type 1 (NF 1). Four cases showed multifocal lesions. Immunohistochemical staining was performed on equivocal cases (25% of the lesions) and all were confirmed by their S-100 positivity. Intraoral neural neoplasms, though uncommon should be in the differential diagnosis of oral soft tissue entities and specific consideration to syndromal linkage is paramount as this may impact patient management.

Identification of intestinal ganglioneuromatosis leads to early diagnosis of MEN2B: role of rectal biopsy

BACKGROUND/PURPOSE

Gastrointestinal symptoms are very common in patients with multiple endocrine neoplasia type 2B (MEN2B) syndrome. Herein, we present a case of intestinal ganglioneuromatosis (IGN) in MEN2B syndrome and a systematic literature review with a special focus on gastrointestinal symptoms prior to the diagnosis of MEN2B.

METHODS

Literature search was performed (years 1966-2015) using the "Pubmed" and "Scopus" databases. Search terms used were gastrointestinal, intestinal and MEN2B.

RESULTS

Literature search revealed 188 publications on MEN2B patients with gastrointestinal symptoms, providing a total of 55 patients including our own case. The far most common gastrointestinal symptom was constipation (72.7%). The onset of gastrointestinal symptoms occurred in 29 out of 55 cases (52.3%) below the age of 1year. However, MEN2B diagnosis was established at a median age of 13.0years (range 0-46years). The histological finding of IGN led to the diagnosis of MEN2B In 15 of 55 patients (27.3%) at a median age of 3years (range 0-31years).

CONCLUSION

Paying close attention to gastrointestinal problems in early childhood and taking a rectal biopsy that precisely screens for IGN offers the chance of diagnosing MEN2B syndrome early in infancy.

A diffuse traumatic neuroma in the palate: a case report

BACKGROUND

A traumatic neuroma is not a true neoplasm but a reactive proliferation of neural tissue that commonly occurs after the transection or damage of a nerve bundle. Traumatic neuromas are rare in the oral region and usually occur as a solitary nodule of the mental foramen, lower lip, or tongue. This is the first report of a diffuse traumatic neuroma of the palate.

CASE PRESENTATION

A 30-year-old Japanese man was referred to our clinic complaining of painful swelling of the left side of his palate. The swelling was diffuse and his pain increased with palpation of his palate. He had no noteworthy medical or family history, and was not aware of any history of trauma or inflammation in his head or neck area. We administered antibiotics and non-steroidal anti-inflammatory drugs because we suspected that his symptoms were the result of inflammation caused by an infection. However, his symptoms did not change. An incisional biopsy was performed, and histopathologic examination indicated that the lesion was a traumatic neuroma. Under general anesthesia the lesion was resected with a 5-mm margin using an electric scalpel because of the diffuse expansion and indistinct borders of the mass. Some tumor cells were observed within the surgical margins of the resected specimen, but there has been no recurrence of either the pain or mass in the 3 years since the surgery.

CONCLUSIONS

The location and diffuse nature of this traumatic neuroma are both very rare. While we were initially unsure about the diagnosis and treatment of this mass, the treatment outcome has been good. However, a postoperative recurrence can occur at any time following the excision of a traumatic neuroma, and close long-term follow-up will continue.

SOS1 frameshift mutations cause pure mucosal neuroma syndrome, a clinical phenotype distinct from multiple endocrine neoplasia type 2B

BACKGROUND

Mucosal neuromas, thickened corneal nerves and marfanoid body habitus are characteristic phenotypic features of multiple endocrine neoplasia type 2B (MEN2B) and often provide an early clue to the diagnosis of the syndrome. Rarely, patients present with typical physical features of MEN2B but without associated endocrinopathies (medullary thyroid carcinoma or pheochromocytoma) or a RET gene mutation; this clinical presentation is thought to represent a distinct condition termed 'pure mucosal neuroma syndrome'.

METHODS

Exome sequencing was performed in two unrelated probands with mucosal neuromas, thickened corneal nerves and marfanoid body habitus, but no MEN2B-associated endocrinopathy or RET gene mutation. Sanger sequencing was performed to confirm mutations detected by exome sequencing and to test in family members and 3 additional unrelated index patients with mucosal neuromas or thickened corneal nerves.

RESULTS

A heterozygous SOS1 gene frameshift mutation (c.3266dup or c.3248dup) was identified in each proband. Sanger sequencing showed that proband 1 inherited the c.3266dup mutation from his affected mother, while the c.3248dup mutation had arisen de novo in proband 2. Sanger sequencing also identified one further novel SOS1 mutation (c.3254dup) in one of the 3 additional index patients.

CONCLUSION

Our results demonstrate the existence of pure mucosal neuroma syndrome as a clinical entity distinct from MEN2B that can now be diagnosed by genetic testing.

Synchronous mucosal Schwann-cell hamartomas in a young adult suggestive of mucosal Schwann-cell harmatomatosis: a case report

Background

Mucosal Schwann-cell hamartoma is a rare mesenchymal polyp that presents in the intestine. Despite lacking ganglion cells, it resembles a gastrointestinal ganglioneuroma.

Case presentation

We report a case of synchronous mucosal Schwann-cell hamartomas in a young male patient, who presented with a single discrete polyp in the mid-rectum and multiple polypoid mucosal lesions in the distal rectum.

Conclusion

To the best of our knowledge, this is the first report of a case of multiple mucosal Schwann-cell hamartomas.

Axonal neuropathy, long limbs and bumpy tongue: think of MEN2B

INTRODUCTION

Multiple endocrine neoplasia type 2 (MEN 2) is an uncommon autosomal dominant cancer syndrome which can be associated with nerve conduction abnormalities.

METHODS

A 14-year-old boy with a family history of consanguinity developed progressive gait clumsiness, pes cavus, hypotonia, and mucosal tumors of the lips and tongue since the age of 3 years. At age 11 years, he was diagnosed with an hereditary motor neuropathy (Charcot-Marie-Tooth syndrome).

RESULTS

Physical examination revealed a Marfanoid habitus, mucocutaneous verrucous tumors, thyroid nodules, and cervical adenopathy. Genetic testing demonstrated the p.M918T mutation in the RET gene, and blood tests showed elevated levels of calcitonin.

CONCLUSIONS

Clinical suspicion in MEN2 is crucial for early diagnosis and subsequent therapy. Mucosal neuroma and a Marfanoid habitus are especially useful. Other neurologic manifestations should not disguise the endocrine disorder, because early diagnosis and treatment of medullary thyroid carcinoma determines the prognosis.

More than just skin deep: faciocutaneous clues to genetic syndromes with malignancies

Genetic syndromes with dermatologic findings and multisystemic involvement (e.g., visceral cancer predisposition) are underrecognized. Patients may have incomplete penetrance and variable expressivity; some patients may solely exhibit subtle skin signs, which create a diagnostic challenge for physicians. Interdisciplinary diagnostic knowledge is required for the early diagnosis and monitoring of patients with these syndromes. Cutaneous changes in the face-one of the most highly exposed areas-can be easily noticed by patients themselves, their families and friends, and physicians; these changes may serve as early indicators of genetic syndromes with malignancies. In this article, we present examples of genetic syndromes with malignancies for which a thorough faciocutaneous examination is helpful in establishing a diagnosis. These examples include lentiginosis-related syndromes (e.g., Peutz-Jeghers syndrome, Carney complex), photosensitivity-related syndromes (Bloom syndrome, Rothmund-Thomson syndrome), and hamartoma-related syndromes (Cowden syndrome, multiple endocrine neoplasia syndrome, tuberous sclerosis complex, Gardner syndrome, Muir-Torre syndrome). The characteristics of these faciocutaneous clues are summarized and discussed. Objective evaluation of these faciocutaneous clues in combination with other clinical information (e.g., family history, histopathological findings, combination with other concomitant faciocutaneous lesions) is emphasized to narrow the diagnosis. The list of genetic syndromes with faciocutaneous manifestations is still expanding. Increased awareness of faciocutaneous markers can alert physicians to underlying syndromes and malignancies, render earlier screening and detection of associated medical issues, and allow for genetic counseling of family members.

Multiple endocrine neoplasias type 2B and RET proto-oncogene

Multiple Endocrine Neoplasia type 2B (MEN 2B) is an autosomal dominant complex oncologic neurocristopathy including medullary thyroid carcinoma, pheochromocytoma, gastrointestinal disorders, marphanoid face, and mucosal multiple ganglioneuromas. Medullary thyroid carcinoma is the major cause of mortality in MEN 2B syndrome, and it often appears during the first years of life. RET proto-oncogene germline activating mutations are causative for MEN 2B. The 95% of MEN 2B patients are associated with a point mutation in exon 16 (M918/T). A second point mutation at codon 883 has been found in 2%-3% of MEN 2B cases. RET proto-oncogene is also involved in different neoplastic and not neoplastic neurocristopathies. Other RET mutations cause MEN 2A syndrome, familial medullary thyroid carcinoma, or Hirschsprung's disease. RET gene expression is also involved in Neuroblastoma. The main diagnosis standards are the acetylcholinesterase study of rectal mucosa and the molecular analysis of RET. In our protocol the rectal biopsy is, therefore, the first approach. RET mutation detection offers the possibility to diagnose MEN 2B predisposition at a pre-clinical stage in familial cases, and to perform an early total prophylactic thyroidectomy. The surgical treatment of MEN 2B is total thyroidectomy with cervical limphadenectomy of the central compartment of the neck. When possible, this intervention should be performed with prophylactic aim before 1 year of age in patients with molecular genetic diagnosis. Recent advances into the mechanisms of RET proto-oncogene signaling and pathways of RET signal transduction in the development of MEN 2 and MTC will allow new treatment possibilities.