A Useful Skin Biopsy

A 10-year-old girl was referred with peculiar non-itchy lumps on her inner arms, legs, and trunks that had been present since one month of age (Fig. 1). She had a history of developmental delays and dry skin. A skin biopsy revealed intradermal deposits of calcium, consistent with calcinosis and osteoma cutis (Fig. 2). Her head circumference was 56 cm (> 97th percentile), weight 24.2 kg (3rd percentile), and height 123.5 cm (< 3rd percentile). The physician suspected Albright osteodystrophy and noted she had a round face with shortened fourth and fifth knuckles and abnormal toes (Fig. 3). Investigations confirmed pseudohypoparathyroidism with low blood calcium (1.23, normal: 2.15–2.55 mM), high phosphate