An unusual case of metaphyseal chondrodysplasia with an abnormal perilacunar matrix associated with agranulocytosis and hypoplasia of the thymus.

We report herein an unusual skeletal dysplasia in a 6-month-old boy characterized by metaphyseal dysplasia associated with agranulocytosis and hypoplasia of the thymus. A radiological survey revealed generalized metaphyseal abnormalities showing widening and increased density. Pathological changes in the chondro-osseous tissues were unusual and distinctive. There was widespread evidence of abnormal chondrocytes with an abnormal perilacunar matrix containing a PAS-positive, diastase resistant substance. Chondrocyte maturation and regular columnar arrangement were absent in most growth plates with only scattered ball-like nests of chrondrocytes showing incomplete maturation. This case is a newly described form of osteochondrodysplasia.