Panlobar nephroblastomatosis with cystic dysplasia: an unusual case with diffuse renal involvement studied by immunohistochemistry.

A unilateral cystic renal process discovered prenatally was removed in a neonate. Dysplastic cysts were associated with diffuse (both intra- and perilobar) nephroblastomatosis. We describe a comprehensive immunohistological study confirming the transition observed on simple histology between the different structures: nephrogenic rests (CD9+, CD24+/-, CD56+/-), glomeruloid bodies (CD10++, CD35++), ducts lined by columnar epithelium (CD9+, CD24+, CD56++), cysts lined by cuboidal or thin epithelium (some cells CD10+, CD26+, others EMA+, CD24+). Although no typical S-shaped bodies are seen, small cysts and ducts with a columnar epithelium are considered similar. The dysplastic primitive ducts are KL1++, vimentin+/-, CD9+, CD24+. With a view to assessing dysplastic preneoplastic potential, the value of CD56 and Ki67 as activation antigens with possible prognostic significance is discussed.