Lethal melanoma in a 2-yr-old with multiple congenital melan
The following case has been reported in the Indian Journal of Dermatology, Venereology, and Leprology.

A 2 -year-old boy presented with multiple brown and black lesions on the back noticed since birth. It was noted that all lesions were flat and did not show changes until 10 months of age.

Examination revealed multiple hyperpigmented plaques of size varying from 0.5 cm to 3 cm. The plaques were mainly distributed on the back but some smaller ones were also found on the subcostal region of right flank. In total, lesions and satellites covered approximately 6% of body surface area. Face, chest, abdomen and limbs were spared. One of the plaques on the back was studded with a nodule of 5 mm × 5 mm size.

Parents did not consent for a skin biopsy. Follow-up visits were advised every 3 months so that the lesions could be monitored through dermoscopy. Nine months later, parents agreed for a skin biopsy. Biopsy was done from the nodule arising from a hyperpigmented plaque on the back. Histopathologically, the tumor was composed of atypical melanocytes infiltrating the entire dermis extensively without any epidermal involvement.

It was shown that the melanocytes had nuclear hyperchromasia. The thickness of the tumor (Breslow) was 7 mm, the Clark level was IV and the tumor stage was evaluated as IIIB. The immunohistochemical examination revealed that atypical melanocytes were positive for S-100. The Ki-67 labelling index in dermal atypical melanocytes was 20–30%. Both HMB45 and Ki-67 positivity of melanocytes in deep dermis were highly suspicious of malignant transformation.

After 4 months the child presented with a 3 cm × 3 cm tumor on the right axilla. Lymph node metastasis was clinically suspected. This case was diagnosed as malignant melanoma arising from a congenital melanocytic nevus with lymph node metastasis.

The child did not receive any computed tomography scans or treatment due to financial constraint. The child died a year after the initial diagnosis. It was informed that the boy was in a coma during the last months of his life. Therefore, it is speculated that he might have developed widespread metastases involving the brain as well. Brain metastasis often occurs when a tumor is located near the spine.

Learning Points:-
• The biggest challenge in diagnosis is to distinguish between melanomas arising from congenital melanocytic nevus and proliferating nodules that develop in congenital melanocytic nevus.

• There are several features that distinguish between proliferating nodule and melanoma:
(1) lack of highly uniform cell atypicality;
(2) lack of necrosis within the nodule;
(3) rarity of mitosis;
(4) evidence of maturation of cells in a mixed or transitional form;
(5) lack of spread into the epidermis and
(6) absence of destructive bloated growth

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