Hyperplasia of parathyroid gland in a five-year old childaffected by MEN 2A

Primary hyperparathyroidism (HPT) is observed in 20-30% of patients with multiple endocrine neoplasia type 2A (MEN 2A). The age of diagnosis ranges from seven to seventy one year old (with median of thirty eight years) in patients affected by HPT in MEN 2A. We diagnosed primary HPT in a 5 year old boy carrier of RET gene mutation associated with MEN 2A,submitted to prophylactic total thyroidectomy (TT). The RET mutated gene carriers are submitted to prophylactic TT at different ages. Recent studies demonstrated that based on the type of RET gene mutation the timing of TT varies, as the transforming potential of RET-mutations are codon-dependentwith significant correlations between genotype and clinical phenotype in MEN 2A patients. In particular, the medullary thyroid carcinoma (MTC) occurs earlier in the patients with codon 634 mutations than in those with other mutations, and these patients have also a higher frequency of pheochromocytoma and hyperparathyroidism. This genotype-phenotype correlation is confirmed in the patient described in this report, who was carrier of a germline mutation in the 634 codon (Cys→Trp) and showed early expression of MTC and parathyroid pathology. The young age of this patient represents an exception, as other Authors report the absence of parathyroid pathology in children or in adolescents submitted to prophylactic TT. The patient underwent a partial parathyroidectomy in agreement with the preferred surgical treatment of HPT in MEN 2A, which consists in removing only the parathyroid(s) with increased volume. Indeed, the experiences with subtotal or total parathyroidectomy associated to autograft are very limited, with results supporting lack of major differences and, therefore, suggesting a more conservative surgical approach HPT in MEN 2A. We diagnosed primary HPT in a 5 year old boy carrier of RET gene mutation associated with MEN 2A, submitted to prophylactic total thyroidectomy (TT). The RET mutated gene carriers are submitted to prophylactic TT at different ages. Recent studies demonstrated that based on the type of RET gene mutation the timing of TT varies, as the transforming potential of RET-mutations are codon-dependent with significant correlations between genotype and clinical phenotype in MEN 2A patients. In particular, the medullary thyroid carcinoma (MTC) occurs earlier in the patients with codon 634 mutations than in those with other mutations, and these patients have also a higher frequency of pheochromocytoma and hyperparathyroidism. This genotype-phenotype correlation is confirmed in the patient described in this report, who was carrier of a germline mutation in the 634 codon (Cys→Trp) and showed early expression of MTC and parathyroid pathology. The young age of this patient represents an exception, as other Authors report the absence of parathyroid pathology in children or in adolescents submitted to prophylactic TT. The patient underwent a partial parathyroidectomy in agreement with the preferred surgical treatment of HPT in MEN 2A, which consists in removing only the parathyroid(s) with increased volume. Indeed, the experiences with subtotal or total parathyroidectomy associated to autograft are very limited, with results supporting lack of major differences and, therefore, suggesting a more conservative surgical approach