Melanoma arising in a Giant congenital melanocytic nevus: two case reports

Abstract Background A giant congenital melanocytic nevus (GCMN) is found in 0.1% of live-born infants. If present, the lesion has a chance of about 6% to develop into malignant melanoma. Both children and adults can be affected by malignant melanoma arising in a giant congenital nevus. Up to 95% of GCMNs harbor NRAS mutations, and mutations in the BRAF, MC1R, TP53, and GNAQ genes have also been described. The individualization of therapy is required, but diagnostic and prognostic criteria remain controversial. Case presentations We report two cases: 1) melanoma arising in a giant congenital nevus during the first month of life complicated with neurocutaneous melanosis (NCM), and 2) melanoma arising in a giant congenital nevus during the first 6 months of life. Pathology, immunohistochemistry, and genetic analyses of tumor tissue were performed. The first case revealed only a non-pathogenic P72R polymorphism of the TP53 gene in the homozygote condition. For the second case, a Q61K mutation was detected in the NRAS gene. Conclusion Malignant melanoma associated with GCMN is rare and therefore poorly understood. Outcomes have been linked to the stage at diagnosis, but no additional pathological prognostic factors have been identified. The most frequent genetic event in giant CMNs is NRAS mutations, which was discovered in one of our cases. To accumulate evidence to improve disease prognosis and outcomes, children with congenital melanocytic nevus should be included in a systemic follow-up study from birth

Prophylactic thyroidectomy results among RET germline mutation bearers in families with hereditary forms of medullary thyroid cancer

Genetically caused medullary thyroid cancer (MTC) is associated with unfavorable survival prognosis, so it makes necessary to develop new diagnostic techniques to reveal pre-clinical stage of disease as well as to introduce into clinical practice the effective method of tumor prevention. The article represents first in Russia summary clinical experience of prophylactic thyroidectomy have been executed in the period 1998 – 2015 yeas among ten bearers of RET gene germlinemutation in families with hereditary disease including syndrome MEN2A and familial MTC. Aim: to evaluate the results of surgical treatment of asymptomatic carriers of germinal mutations in the RET gene. Materials and methods. In the period from 1998 to 2015, in two centers: N.N. Blokhin Russian Cancer Research Center, Moscow and A. Tsyb Medical Radiological Research Centre – branch of the National Medical Research Radiological Centre, Obninsk was conducted prophylactic surgical treatment in 10 patients – asymptomatic carriers of germinal mutations in RET. Age of patients – from 2 to 23 years old. 9 patients – from families with the syndrome of multiple endocrineneoplasia type 2A (MEN2A), one – with the family of MTC. According to genealogy in 9 families of patients there have been cases of death from MTC or pheochromocytoma (PC). In all cases, surgical treatment was performed in a volume of TE, two patients additionally performed lymph node dissection VI level. The observation period after surgery ranged from 6 months to 16 years. Results. DNA diagnostics in 8 patients identified a mutation in exon 11, in one case – in exon 10 and one patient had revealed two mutations in exons 13 and 14. The age of patients ranged from 2 to 23 years. Basal calcitonin level was elevated in 7 of 10 patients. Such prophylactic TE in 2 patients was supplemented by selective lymph node dissection. Histological examination of the removal of the thyroid gland (TG) revealed foci of medullary cancer in 6 of 10. At 2 patients revealed a C-cell hyperplasia and at 2 patients were found signs of the well expressed and weakly expressed sclerosis in thyroid tissue. The earliest age to identify MTC was a child 3 years old, mutations in codon 634, from a family where relatives observed for aggressive MTC. In the course of follow-recurrence was detected in one patient, a child of 15 years, a similar mutation carrier. Conclusion. In view of the risk of MTC developing identifying a mutation in RET gene and preventive TE should be carried out as soon as possible. The high risk of MTC developing in RET-gene positive subjects was confirmed in this study (6 cases of cancer from 10 patients)