Phacomatosis Pigmentokeratotica: Case Study

Background. Phacomatosis pigmentokeratotica (PPK) is an orphan genodermatosis from the epidermal nevus syndrome group. This disease is caused by somatic mosaicism predominantly in the HRAS gene. Pathognomonic PPK sign is combination of congenital linear nevus sebaceus of Jadassohn and speckled lentiginous nevus. Second one may debut much later. In some cases, there are signs of nervous system damages, skeletal disorders, visual impairments. Case description. Description of a patient with PPK and novel for this disease mosaic variant G469A in the BRAF gene is presented. Clinical picture included typical signs of the syndrome and immunological disorders unusual for patients with PPK. Possible genotype-phenotype correlations were analyzed based on 16 previously published observations of genetically verified PPK. Conclusion. The syndrome rarity, its course variability, and patients genetic testing features determine the difficulties in PPK diagnosis. The disease should be considered not only in terms of dermatological signs, but also regarding comorbid disorders. The dynamic follow-up should include consultations of pediatric oncologist, neurologist, ophthalmologist, endocrinologist, orthopedist, cardiologist, and immunologist.