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Pathological features of multiple endocrine neoplasia type IIb in childhood
R W Byard1, P S Thorner, H S Chan
1Department of Pathology, Hospital for Sick Children, Toronto, Ontario, Canada.
Insights
Multiple Endocrine Neoplasia type IIb (MEN2B) can present with subtle gastrointestinal and neck symptoms. Early recognition is crucial to avoid delayed diagnosis of associated medullary thyroid carcinoma.
Area of Science:
- Endocrinology
- Gastroenterology
- Oncology
Background:
- Multiple Endocrine Neoplasia type IIb (MEN2B) is a rare genetic disorder.
- MEN2B is characterized by medullary thyroid carcinoma, pheochromocytoma, and mucosal neuromas.
- Marfanoid habitus is a common feature in MEN2B patients.
Observation:
- Two pediatric patients with MEN2B presented with distinct symptoms: chronic constipation and failure to thrive (Patient 1), and cervical lymphadenopathy (Patient 2).
- Histopathological examination revealed disorganized, hyperplastic ganglion cells in the intestinal nerve plexuses of Patient 1.
- Patient 2 exhibited a submucosal neuroma of the tongue and cervical lymph node metastases.
Findings:
- Both patients were diagnosed with occult medullary thyroid carcinoma.
- Neoplastic cells showed positive staining for cytokeratin, carcinoembryonic antigen, calcitonin, bombesin, chromogranin, serotonin, and Leu 7.
- Immunohistochemistry and electron microscopy confirmed neurosecretory granules and calcitonin-positive amyloid in Patient 2.
Implications:
- These cases highlight the diagnostic challenges and potential delays in identifying MEN2B.
- Awareness of diverse clinical presentations is essential for timely diagnosis and management of MEN2B.
- Early detection of MEN2B can significantly improve patient outcomes by facilitating prompt treatment of associated malignancies.
Abstract:
The features of two patients with multiple endocrine neoplasia type IIb are described. Patient 1, a 9-year-old boy with marfanoid features, presented with chronic constipation and failure to thrive since infancy. Patient 2, a 12-year-old boy with marfanoid features, presented with a five-year history of persistent cervical lymphadenopathy. In patient 1, the myenteric and submucosal nerve plexuses at all levels of the small and large intestines were comprised of diffusely disorganized, hyperplastic, mature ganglion cells and nonmyelinated nerve fibers. Nerve plexus dissection with morphometric analysis showed marked thickening of the myenteric plexus with a quantitative increase in neural tissue. Patient 2 had a submucosal neuroma of the tongue. Both patients had occult medullary thyroid carcinoma, and patient 2 had cervical lymph node metastases. Both neoplasms showed positive staining for cytokeratin, carcinoembryonic antigen, calcitonin, bombesin, chromogranin, serotonin, and Leu 7. Electron microscopy showed membrane-bound, intermediate-sized, dense-core neurosecretory granules in tumor cells. In patient 2, calcitonin-positive amyloid was present with localization of calcitonin by immunoelectron microscopy to cytoplasmic secretory granules and to extracellular amyloid fibrils. These cases illustrate the potential for missed or delayed diagnosis in multiple endocrine neoplasia syndromes.