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Case 31 - Discussion

Surgical Pathology Case

 

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Microscopic Description
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 neoplasm.

ELECTRON MICROSCOPY:
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, Omaha, NE.)
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.
NOMENCLATURE: 46,XY,t(6;13)(q15;q34),del(20)(q13.1)[8]/46,XY[12]

Diagnosis: Giant cell reparative granuloma of bone, a variant of aneurysm bone cyst

  Reference: Pan Z, Sanger WG, Bridge JA, Hunter WJ, Siegal GP, Wei S. Hum Pathol. A novel t(6;13)(q15;q34) translocation in a giant cell reparative granuloma (solid aneurysmal bone cyst). 2012 Jun;43(6):952-7