Epidermal nevus syndrome with hypophosphatemic rickets in a young girl

Epidermal nevus syndrome (ENS) is a rare congenital disorder. It is characterised by epidermal nevi and abnormalities of multiple organs, including central nervous system, skeleton, cardiovascular and genitourinary systems and eyes. Hypophosphatemic rickets-associated ENS has rarely been reported. We report a 46-month-old girl who presented with a classical feature of hypophosphatemic rickets. Examination of skin revealed multiple melanocytic nevi at her trunk, face and both arms with verrucous plaques at both axillae and neck, and yellow plaques at the back along Blaschko's lines. Histopathology of the skin lesions was compatible with epidermal nevi and nevus sebaceous. Therefore, the diagnosis of ENS was made. Apart from typical rickets, the skeletal X-rays interestingly displayed fibrous dysplasia-like lesions along right femur, tibia and fibula. Hypophosphatemic rickets was treated with alfacalcidol and phosphate solution. After 3 months of treatment, clinical improvement of hypophosphatemic rickets was clearly demonstrated. Her blood chemistries were normalised at 5 months following the treatment. In conclusion, hypophosphatemic rickets is a rare presentation of ENS. Our patient also demonstrated an additional abnormal bone finding, fibrous dysplasia-like lesions, associated with rachitic changes. This highlights heterogeneity of this condition and importance of thorough evaluation of patients with ENS.