IntroductionCongenital melanocytic nevi (CMN) denote benign melanocytic proliferations, affecting approximately 1 to 2% of newborns, with a higher prevalence observed among Asian and Black children1,2. Manifesting either at birth or within subsequent weeks, these nevi typically manifest as light brown to black patches or plaques, varying in size and distribution across the body. Classification commonly stratifies CMN into small (< 1.5 cm), medium-sized (1.5 to 19.9 cm), and large or giant (20 cm or greater) lesions 3,4. Described as ’garment or bathing trunk’ nevi, large lesions are infrequent, with an incidence ranging from 1:200,000 to 500,000 births and a notable female predilection3. They are often deeply pigmented, accompanied by moderate hair growth, and frequently associated with scattered satellite lesions. While the hairy component, present in 95% of cases, tends to become more prominent in late childhood, the nevus itself typically pales at this stage 1.Giant nevi may exhibit associations with several comorbidities, including neurocutaneous melanosis, diffuse lipomatosis, structural brain malformations, skull bone hypertrophy, limb atrophy, skeletal asymmetry involving soft tissue hyper- and hypoplasia, von Recklinghausen’s disease, and vitiligo 5. The likelihood of neoplastic transformation is directly proportional to CMN size, with an estimated incidence ranging from 6% to 12% over one’s lifetime 6. The emergence of firm nodules warrants vigilant attention, with differential diagnoses encompassing proliferative nodules and malignant melanoma 4. Malignant transformation within giant CMN predominantly occurs in axial locations, with extremity lesions presenting lower risk, and satellite nevi exhibiting negligible risk 6.The cornerstone of treatment for large congenital melanocytic nevi remains surgical excision, often employing staged excision and subsequent resurfacing via skin grafts, tissue expanders, or flaps for giant lesions 5. In this report, we document a case involving a male adolescent presenting with a giant congenital nevus accompanied by lipomatosis localized to the right flank.