Multiple endocrine neoplasia syndrome — type 2b

Common conditions associated with mandibular canal widening: A literature review

Purpose

The aim of this study was to review the common conditions associated with mandibular canal widening.

Materials and Methods

General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus were used to find relevant studies by using the following keywords: “mandibular canal,” “alveolar canal,” “inferior alveolar nerve canal,” “inferior dental canal,” “inferior mandibular canal,” “widening,” “enlargement,” “distension,” “expansion,” and “dilation.”

Results

In total, 130 articles were found, of which 80 were broadly relevant to the topic. We ultimately included 38 articles that were closely related to the topic of interest. When the data were compiled, the following 7 lesions were found to have a relationship with mandibular canal widening: non-Hodgkin lymphoma, osteosarcoma, schwannoma, neurofibroma, vascular malformation/hemangioma, multiple endocrine neoplasia syndromes, and perineural spreading or invasion.

Conclusion

When clinicians encounter a lesion associated with mandibular canal widening, they should immediately consider these entities in the differential diagnosis. Doing so will help dentists make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

Radiographic Enlargement of Mandibular Canal as an Extranodal Primary Non-Hodgkin's Lymphoma Early Sign in an Asymptomatic Patient

Non-Hodgkin's lymphoma (NHL) is a lymphoproliferative disorder, from a subgroup of heterogeneous hematologic malignancies; the term “extranodal” refers to malignant involvement of tissues other than lymph nodes, tonsils, spleen, pharyngeal lymphatic ring, or thymus. Only 0.6% of all NHL are at mandible alone, and it may involve the inferior alveolar canal. We describe a case of bilateral enlargement of the mandibular canal without symptomatology, which was shown in a panoramic radiograph and cone beam computed tomography in a rehabilitation routine exam, as an early sign of primary extranodal NHL.

Oral Manifestations and Molecular Basis of Oral Genodermatoses: A Review

Genodermatoses refers to group of inherited monogenic disorders with skin manifestations. Many of these disorders are rare and also have oral manifestations, called oral genodermatoses. This article provides a focused review of molecular basis of important genodermatoses that affects the oral cavity and also have prominent associated dermatologic features. In several conditions discussed here, the oral findings are distinct and may provide the first clue of an underlying genetic diagnosis. The article also emphasises on the prenatal diagnosis, genetic counselling and the treatment oral genodermatoses.

Multiple endocrine neoplasia-2B presenting with orthodontic relapse

The multiple endocrine neoplasia (MEN) syndromes are a relatively uncommon group of genetic disorders characterized by the development of tumors in various endocrine organs. MEN type 2B is of particular interest to the dental profession because of its oral manifestations, which are often some of the earliest clinically detectable signs of the disorder. Early identification of this syndrome is critical because affected patients often develop a characteristic malignancy, medullary carcinoma of the thyroid, at a very early age. We describe a 17-year-old male whose initial diagnosis of MEN-2B was triggered by his orthodontist's request for an oral and maxillofacial pathology consultation to evaluate the patient's oral abnormalities.

Ocular findings in a child with multiple endocrine neoplasia type 2b

A 16-year-old girl was admitted with severe bilateral conjunctival hyperemia and stinging lasting for more than 1 year. Slit-lamp biomicroscopic examination revealed extremely thickened corneal nerves and multiple small plexiform subconjunctival neuromas. Both eyes had thickened upper and lower eyelids and a neuroma was found on the left upper conjunctival lid margin. On physical examination, a 2 x 3 cm nodule was detected within the thyroid gland. Medullary thyroid carcinoma was diagnosed by fine needle aspiration biopsy and thyroidectomy ensued. Further investigation with abdominal computed tomography revealed a pheochromocytoma (3 x 4.5 x 2 cm) of the right adrenal gland, which was removed surgically. Ophthalmologists must remember multiple endocrine neoplasia 2b in the presence of greatly thickened corneal nerves and subconjunctival neuroma because this may be the first sign of the disease. Early diagnosis and prophylactic thyroidectomy may be life saving.

Widening of the inferior alveolar canal: a case report with atypical lymphocytic infiltration of the nerve

Widening of the inferior alveolar (mandibular) canal is a rare radiological finding. It is most often associated with neurofibromatosis. Rarely, a malignant process such as lymphoma may cause ill-defined enlargement of the mandibular canal. We present a unique case of a 33-year-old male who gradually developed sensory loss of his left lower lip and cheek and a well-defined tube-like widening of his left mandibular canal. The histopathological findings of the lesion were unusual in that they indicated atypical lymphocytic infiltration of the nerve tissue. The differential diagnoses regarding the clinical, radiological, and histopathological findings are discussed.

Oral manifestations of genodermatoses

Many genodermatoses have distinct oral features that may help identify or confirm a genetic diagnosis. Oral features of the disorders described here are summarized in Table 1. These conditions provide clear examples of rapid progress in the field of genetic technology relevant to patient care. Less than a decade ago, the exact genetic locus of most of these disorders was unknown. Today, for many of these disorders, the exact location of the disease-causing mutation is known and clinical genetic testing is available for patients. This information has impact not only for genetic counseling and anticipatory medical care, but also provides insight into the mechanisms of disease. How this rapid progress will impact care, and ultimately treatment of patients, remains to be seen.

Enlargement of mandibular canal without hypesthesia caused by extranodal non-Hodgkin's lymphoma: a case report

A rare condition of enlargement of the mandibular canal caused by an extra-nodal non-Hodgkin's lymphoma in a 59-year-old Japanese woman was reported. The patient had a swelling of the hard palate and protrusion of both ocular bulbs, which had been present for 10 years. A panoramic radiograph revealed that the right mandibular canal was widely enlarged, extending from the mandibular foramen to the mental foramen, without bone destruction. The continuous dilation of the mandibular canal to an approximate 15-mm width was associated with peripheral bony sclerosis. Computed tomography and magnetic resonance imaging showed a soft tissue tumor inside the mandibular canal. The lesion demonstrated expansive growth in the orbits, extending to the skull base through the superior orbital fissures and cavernous sinus. The lymphoma was suspected to have grown so slowly that the adjacent mandibular canal and ocular bulbs enlarged without destroying the normal bone and nervous tissue.

A case of multiple endocrine neoplasia type 2B

A sporadic case of multiple endocrine neoplasia type 2B in a twenty-six year old man who manifested medullary thyroid carcinoma, multiple mucosal neuromas of the tongue and a marfanoid habitus is reported. At the time of diagnosis, he also had multiple liver and lung metastases. Genetic analysis of his lymphocytes revealed a point mutation in exon 16 of the RET proto-oncogene. Since multiple endocrine neoplasia type 2B has a relatively poor prognosis because of the occasional aggressive behavior of medullary thyroid carcinoma, the necessity of the genetic diagnosis of multiple endocrine neoplasia in the early stage is suggested.

RET protooncogene mutational analysis in multiple endocrine neoplasia syndrome type 2B: case report and review of the literature

Multiple endocrine neoplasia, type 2B (MEN 2B), is a phenotypic variant of a group of autosomal-dominant neurocristopathies. MEN 2B is associated with medullary thyroid carcinoma and pheochromocytoma with oral, ocular, and alimentary submucosal ganglioneuromas and Marfanoid body features. Approximately 50% of cases are thought to be spontaneous mutations. The RET protooncogene (RET) is a 21-exon gene encoding a tyrosine kinase receptor. A codon 918 germ line mutation, which converts a highly conserved methionine to a threonine in the intracellular tyrosine kinase portion of this receptor of RET, has been identified in 95% of patients with MEN 2B. This mutation is easily detected by a direct deoxyribonucleic acid sequencing or restriction enzyme (Fok 1) analysis of amplified polymerase chain reaction products. The RET gene is normally expressed in the oral and gastrointestinal submucosal neural ganglia, and the codon 918 mutation is thought to cause neuromas by virtue of its transforming activity in these ganglia. Identifying clinical features of MEN 2B in an 11-year-old boy by an oral pathologist led to confirmation by mutational analysis. Before genetic testing was available, the patient, and at a later date his mother, underwent thyroidectomies based solely on biochemical testing. Results indicated the patient had the codon 918 mutation, whereas his phenotypically normal mother, father, and older brother had normal RET analyses. Studies in families have demonstrated that the mutant allele is derived from the father with possible acquisition during spermatogenesis. We believe the mother of our affected patient to be normal; the absence of phenotypic features of MEN 2B and a normal genotype suggest her calcitonin abnormalities and minimal evidence for C-cell hyperplasia were inconsequential. Molecular analysis for RET abnormalities will likely supplant biochemical methods of diagnosis in patients with MEN 2B.

Multiple endocrine neoplasia syndrome, type III: review and case report

Successful treatment of the multiple endocrine neoplasia type III (MEN III) syndrome requires early diagnosis. It is highly possible that the patient's dentist may be the first practitioner with the opportunity to diagnose this potentially fatal syndrome. Additionally, patients with this syndrome having a pheochromocytoma and needing invasive dental treatment pose a life-threatening dental management risk. This article presents a review of the MEN II syndrome and a case report on the surgical management of a MEN III patient with a pheochromocytoma.