Solitary irregular hyperkeratotic and eroded plaque on the shoulder of a child

A 2-year-old child presented with a localized hyperpigmented, hyperkeratotic, and irregular plaque with a persistent erosion on her right posterior shoulder (Figure 1). This lesion had been present since birth. Her family history was positive for generalized Darier's disease in her father and paternal grandmother. There were no other cutaneous findings or signs of systemic disease. To date, the patient's developmental milestones have been normal. A skin biopsy of the affected skin was performed (Figures 2a-2b).