FIGURE 1.

A, This gross photograph of a bivalved kidney from a 19-year-old female with segmental hypoplasia shows a single deep groove characteristic of segmental hypoplasia. The kidney was 7 cm long (normal: 11 to 12 cm). The hypoplastic focus is tan with no evidence of corticomedullary differentiation. The adjacent cortex appears normal. The underlying collecting system shows marked hydronephrosis. B, This gross photograph of a bivalved kidney is from a 33-year-old female with segmental hypoplasia. The kidney was 6 cm long and weighed 38 g (normal: 115 to 125 g). Four hypoplastic foci were preset; 3 are visible in this photograph. C, This gross photograph of a bivalved kidney from a 2-year-old female was 2.5 cm long (normal: 5.5 to 7.8 cm) and weighed 3 g (normal: 35 to 50 g). There are several adjacent hypoplastic foci without intervening normal lobes. Two normal lobes are at the top and on the right, respectively. D, This gross photograph of a child with segmental hypoplasia shows the deep circumferential groove characteristic of this entity. Jay Bernstein Consultative Collection, with permission.