Case 14

A 7 year-old female presented with pain and limp about the hip.
    A: An AP radiograph of the hip at presentation. The presenting radiograph shows a large, well-circumscribed radiolucent process in the iliac neck and wing with disruption of the subchondral plate of the acetabulum superiorly. There is very little reactive bone about the lesion.
A biopsy was done.
    B: The curettings from the biopsy. The tissue was soft, buttery yellow, with little vascularity. The buttery yellow coloration is suggestive of lipid material.
    C: A low power field from the curettings. The low power field shows a mass of cellular tissue with no stroma or matrix.
    D: A high power field from the same tissue. The higher power field is composed of an admixture of densely basophilic inflammatory cells interspersed with larger lightly stained histiocytes. The histocytes have several vacuolated clear areas in their cytoplasm. The vacuoles contain lipid - hence the buttery yellow color of the tissue.
    E: Magnification of the previous field. The magnified field shows several of the inflammatory cells have a multilobed nucleus and an eosinophilic stain of their cytoplasm.

Cultures of the tissue produced no growth.

Diagnosis: eosinophilic granuloma.

The cavity was thoroughly curreted without bone grafting.