ESPE Abstracts

Introduction: Multiple endocrine neoplasia 2B (MEN2B) is a rare cancer syndrome primarily caused by the M918T (95%) and A883F (<5%) germline mutations in the REarranged during Transfection (RET) proto-oncogene. Aggressive and early onset thyroid medullary carcinoma is the hallmark of the disease. Cure rates in M918T carriers who had thyroidectomy before and after 1 year of age were 83% and 15% respectively. More than 80% arise due to de novo mutations challenging the recommendation of thyroidectomy before 1 year of age as extra-endocrine features are subtle in infancy.

Case: We report a girl born by spontaneous vaginal delivery at gestational age 24 + 6 weeks who was unwell with aspirates, abdominal distention and constipation from day 1. Passing of meconium did not occur until day 3 of life. At age 3 weeks abdominal symptoms worsened with increasing amounts of green aspirates and lactate rise. Necrotizing enterocolitis (NEC) was suspected. A laparotomy confirmed chronic paralytic ileus in accordance with dilated bowels on previous abdominal films, and without NEC, malrotation or stenosis. In spite of motility stimulating drugs and rectal washouts, symptoms did not improve, and the girl was failing to thrive. At age 10 weeks she was given an ileostomy to deflate the bowels and alleviate secondary compromised breathing. Proximal to the stoma the bowels were noted to be extremely dilated as opposed to distally where they were collapsed. The pathology report from a specimen of excised bowel described intestinal ganglioneuromatosis. At age 12 weeks genetic analysis confirmed the RETM918T germline mutation aided by the history as the mother had informed, she carried this mutation.

Discussion: Dysmotility in MEN2B is due to abnormal proliferation of intramural ganglion cells resembling symptoms of Hirschsprung's disease. Gastrointestinal problems with severe constipation and pseudo obstruction are common (65%) in MEN2B and may present already in premature neonates. With increasing age marfanoid body proportions, mucosal neuromas, alacrima, corneal hypertrophy and musculoskeletal symptoms start to present.

Conclusion: Awareness and identification of extra-endocrine features occurring in early life for clinicians to suspect MEN2B is paramount for early diagnosis and timely prophylactic thyroidectomy.