The Cutaneous Manifestations of McCune-Albright Syndrome: A Rare Case Report

McCune-Albright syndrome (MAS) is a rare and complex nonhereditary genetic disorder affecting the bones, skin, and endocrine system. The estimated prevalence of this rare sporadic disease ranges from 1 in 100,000 to 1,000,000. It is clinically defined by a triad of fibrous dysplasia, café-au-lait macules (CALMs), and hyperfunctioning endocrinopathies. We report an 11-year-old boy presenting with widespread brownish patches, postural changes, and limited mobility due to spinal deformities. Physical examination revealed skeletal abnormalities, breast budding, and scoliosis. Skin and dermoscopic examinations were conducted to assess CALMs. Although CALMs are common in MAS, their presentation may overlap with other disorders, creating diagnostic challenges. Our patient also exhibited hypertrichosis, a finding not classically associated with MAS whose relationship to the syndrome remains uncertain despite occasional reports. In MAS, hyperpigmentation results from increased melanogenesis caused by a GNAS gene mutation. CALM can resemble lesions in neurofibromatosis; however, distinct clinical features such as irregular borders and segmental distribution aid in differentiation. Dermoscopy further helps distinguish CALM from congenital melanocytic nevi and Becker’s nevus, supporting accurate diagnosis. This case highlights the clinical importance of recognizing atypical and overlapping cutaneous manifestations of MAS and highlights the diagnostic value of dermoscopy in pediatric patients.