Multiple sections, including decalcified sections, show a cystic
hemorrhagic neoplasm consisting of plump fairly spindle shaped cells
interspaced by osteoclast-like giant cells that may contain up to 50
nuclei. The neoplasm is richly vascularized. The slit-like spaces
are not lined by a vascular endothelium. Some hemosiderin laden
macrophages are present. Occasional areas of osteoid is noted. There
are areas of bone destruction and reabsorption, along with areas of
new bone growth. The tumor is fairly well circumscribed and does not
extend into the surrounding soft tissue. In some areas there is a
dense fibroblastic reaction. All margins of resection are free of
Ultrastructurally, there are sheets of plump fusiform
fibroblast-like cells with moderately developed Golgi apparatus and
rough endoplasmic reticulum. An occasional lipid droplet is present
within these cells. These cells are embedded in a fibrillary matrix.
Interspersed are giant cells which contain relatively small nucleoli
with marginated chromatin. The cytoplasm of giant cells show
abundant mitochondria, multiple Golgi and numerous vesicles.
(Interpretation performed by Drs. Hunter and Pan. Performed in the
Electron Microscopy Laboratory, Creighton Medical Laboratories,
ULTRASTRUCTURAL IMPRESSION: Giant cell tumor of bone.
CYTOGENETICS REPORT (performed at University of Nebraska Medical Center Human Genetics
Laboratory, Omaha, NE, report on file):
Cytogenetic analysis revealed the presence of an abnormal diploid
clone characterized by a reciprocal translocation between 6q and 13q
and a deletion of 20q. Twelve cells were normal male.
Giant cell reparative granuloma of bone, a variant of aneurysm bone