209 Are kindey malformations possible feature of men2b syndrome? – report of a patient with men2b, type 1 diabetes, situs viscerum inversus and kidney malformations

Multiple endocrine neoplasia Type2b (MEN2b) is a rare familial syndrome caused by autosomal dominant mutations in the RET protooncogen. Patients with MEN2b suffer from aggressive form of medullary thyroid cancer (MTC), pheochromocytoma, multiple mucosal neuromas, gangliomatosis of gastrointestinal tract, and a marfanoid habitus, whereas hyperparathyroidism is exceedingly rare.AimTo present a patient with MEN2b, diabetes mellitus type 1, situs viscerum inversus and hydronephrosis with megacystis-megaureter syndrome and explore possible etiologic associations between those entities.Case ReportOur patient was born from a normal pregnancy, at term. Fetal ultrasound imaging ‘in utero’ revealed bilateral dilation of ureters (megaureter), hydronephrosis, duplicated ureters, and situs inversus. On the 2nd day of life bilateral percutaneous nephrostomies were inserted. At the age of two years right upper pole heminephrectomy for ectopic ureter and antireflux surgery of the lower ureter were performed. He has been followed-up by pediatric surgeon and nephrologist. Kidney function was normal, he didn’t show any symptoms and didn’t require any treatment. At the age of 7 years he was diagnosed with type 1 diabetes. When he was 11,5 years old, during regular follow-up visit, an ultrasound examination of the thyroid gland revealed suspicious nodule and brought to attention an unusual appearance of the patient: thick, prominent lips with submucosal nodules, marfanoid body habitus, musculature weakness and hypotrophy, high arched palate- suggesting MEN2b syndrome. Laboratory evaluation (high calcitonin level) and pathohistological examination of extirpated thyroid confirmed metastatic medullary thyroid carcinoma. Molecular genetic analysis found RET-proto-oncogene patogenic variant: c.2753T>C (p. Met918Thr) confirming MEN2b syndrome. There were no signs of pheochromocytoma.ConclusionTo the best of our knowledge there are no reports on association of MEN2b and type 1 diabetes or reversed position of major visceral organs. However, there are scarce reports on kidney malformations in patients with MEN2b. Acknowledging a recognised role of RET gene in kidney development, we suggest that kidney malformations might be a feature of MEN2b syndrome that should be looked for.