A female baby (G1P1 38 + 6 weeks gestation) was born via cesarean section, weight 2.89 kg, no fetal distress, birth without asphyxia. The physical parameter were: body temperature 36.8 ℃, heart rate 152/min, and respiration 46/min. Serum total bilirubin was 123.7umol/L (3.4–17.7). The child was born with a huge nodular mass (3.0 cm×5.0 cm×9.0 cm) on her right shoulder. The skin on the surface of the tumor appeared black, with skin ulceration about 1 cm×1 cm on the top, accompanied by a small amount of bright red blood exudation (Fig.
1a). No melanin plaques were observed on the skin of other parts of the patient’s body. Magnetic Resonance Imaging (MRI) revealed that the tumor was located on the right shoulder and underarm in a lobulated appearance, and surrounded the right scapula which was deformed (The right scapula showed irregular spots and patchy bone destruction. The bone was discontinuous, with infiltrating tumor) (Fig.
1b), Clinical stage:IV(AJCC 8th Edition (2017)).The findings of AFP by hematological examination were 1210ng/ml (50-100000), NSE: 21.28ng/ml (0-16.3), LDH: 842U/L (67-394.1). The patient was found to have a mass of 2.97 cm×1.82 cm×1.5 cm on the right acromion in the color Doppler ultrasound examination at 24 weeks of pregnancy. Her parents and other family members denied a family history of any disease (hereditary, infectious, or similar diseases), mental illness, and malignant tumors. The infant underwent tumor resection and pathological examination. General examination of the tumor found the presence of a gray-red and dark-red skin mass measuring 9.0 cm×5.0 cm×4.0 cm with an incomplete capsule that was mostly black in color. A 2.0 cm×1.5 cm sized ulceration was seen on the surface of the mass (Fig.
2a). The section observed was solid and black, and necrosis was also present in certain parts (Fig.
2b). Histopathological examination revealed that the tumor cells in the dermis were distributed in sheets or nests (Fig.
2c), with round or oval nuclei, in which some nucleoli were evident and nuclear divisions were common. A large amount of melanin was seen in the cytoplasm, and local epithelium was absent. Infiltration and necrosis of neutrophils was observed, and the tumor invaded striated muscles,residual tumor was seen in the local margin (Fig.
2d). IHC staining showed the expression of S-100 (+), HMB45 (+), Melan A (+) (Fig.
2e), SOX10 (+) and Tyrosinase (+) (Fig.
2f), Ki67 (+, hot spots 15–20 %), CK (-), CD163(-). 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). Final pathological diagnosis verified the mass as neonatal congenital nodular MM, Breslow T4b, Clark V. Since the patient was a newborn, non-operative treatment such as chemotherapy and radiotherapy were not carried out after 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.