Spitzoid proliferative nodules arising in a congenital melanocytic naevus: A case report with clinical, dermoscopic and histologic correlation.

Proliferative nodules (PNs) are benign nodular proliferation of melanocytes occurring within congenital melanocytic naevi (CMN). Differential diagnosis between PN and melanoma is challenging for clinicians and pathologists. We describe the case of a 9-month-old boy who developed multiple nodules arising in a medium-sized CMN. Clinically, pink papules were observed, with dotted vessels on dermoscopy, suggesting spitzoid PN. On histopathological examination, the dermoscopic findings correlated with the vertical vessels of a spitzoid PN. Dermoscopy could be a useful tool to differentiate PN from melanoma. However, further studies describing the dermoscopic features of the different PN subtypes are needed. Histopathology remains the gold standard for definitive diagnosis aided by ancillary molecular tests such as fluorescence in situ hybridization or comparative genomic hybridization.

Giant congenital nodular melanoma in a newborn: a case report and literature review.

BACKGROUND: Malignant melanoma (MM) arises predominantly after adolescence and is uncommon in children. Congenital MM in newborns is even rarer with a dearth of published literature; as a consequence, there is no uniform standard for the pathogenesis and treatment for neonatal malignant melanoma. Herein we report a case of giant congenital nodular MM in a newborn, including its clinical, imaging, pathological and molecular pathological features. This case is the largest giant congenital primary nodular malignant melanoma in utero in neonates currently reported in China. CASE PRESENTATION: A female neonatal patient was found to have a 2.97 cm× 1.82 cm×1.50 cm mass with a clear boundary at the right acromion in color Doppler ultrasound examination at 24 weeks of gestation. The mass increased to 3.0 cm×5.0 cm×9.0 cm at birth, and local ulceration was seen. MRI demonstrated that the mass was located on the right shoulder and underarm in a lobulated appearance, and surrounded the right scapula which was deformed. Clinical stage:IV(AJCC 8th Edition (2017)). α-Fetoprofein (AFP) by hematological examination: 1210ng/ml, NSE: 21.28ng/ml, LDH: 842U/L. The patient underwent surgical resection of the tumor, and was pathologically diagnosed as neonatal congenital malignant melanoma; immunohistochemistry (IHC): S-100 (+), HMB45 (+), Melan A (+), and Tyrosinase (+). Molecular pathological examination for BRAF V600E showed no mutations (Quantitative Real-time PCR, qPCR); And so were NRAS, C-kit (exons 9,11,13,14,17,18), and TERT (promoter locus, C228T and C250T) (Sanger sequencing). Non-surgical therapies were not carried out after the surgical resection of the tumor. After 6 months of follow-up, the child developed normally, and color Doppler ultrasound showed no obvious tumor growth or abnormality in the original tumor site. CONCLUSIONS: It is extremely rare to see giant congenital primary nodular MM in utero in neonates. The pathogenesis, treatment and prognosis of congenital MM need further research. The diagnosis mainly depends on histopathology and immunohistochemistry, and it needs to be differentiated from malignant lymphoma and primitive neuroectodermal tumor. The current treatment strategy for MM relies on the surgical excision of the mass. Research directed at molecular detection for genetic mutations would contribute to targeted therapy and better prognosis.

Next-generation sequencing revealing TP53 mutation as potential genetic driver in dermal deep-seated melanoma arising in giant congenital nevus in adult patients: A unique case report and review of the literature.

Melanoma in giant congenital nevus (M-GCN) is a rare and potentially lethal neoplasm. In children, M-GCN appears as a dermal/deep-seated melanoma (DDM-GCN) with histopathologic features difficult to distinguish from proliferative nodules (PNs-GCN). DDM-GCN in adults is an anecdotal entity and only 8 cases have been described and genetically characterized. We report the first case of DDM-GCN in a 34-year-old man characterized with a large-panel next-generation sequence (NGS) highlighting a TP53 mutation with a UV-signature (C>T substitution) in DDM but not in PNs-GCN and GCN. Curiously, DDM showed an aberrant p16 overexpression without detection of CDKN2A mutation at NGS. In line with previous studies, it supports a different pathway in children and adults: UV-induced mutations may be involved in the latter not only by CDKN2A but also by TP53 mutations, with a potentially confusing overexpression of p16 protein. While these data need to be confirmed in larger cases series, our results show that NGS could be an additional genetic diagnostic tool in DDM-GCN.