Intraosseous hibernoma: characterization of five cases and literature review.
OBJECTIVE
To describe the imaging and histopathological findings and provide an overview of a recently described and rare cause of bone sclerosis.


METHODS
Five cases of intra-osseous hibernoma of bone that presented over the last year. The imaging and histopathology is reviewed.


RESULTS
All cases were identified in asymptomatic middle-aged to elderly adults as incidental findings with bone sclerosis in the axial skeleton. MRI showed lesions that were T1 hypointense to subcutaneous fat and hyperintense to skeletal muscle and one showed contrast enhancement. Glucose avidity was demonstrated on FDGPET in both cases tested and isotope bone scan performed in three cases showed strong positivity in two, but uptake was inconspicuous in one case.


CONCLUSIONS
Intra-osseous hibernoma is a rare cause of sclerotic bone lesions, predominating in the axial skeleton of middle-aged and elderly adults. They have a non-aggressive appearance on CT and on MRI are T1 hypointense to subcutaneous fat and hyperintense to skeletal muscle. They are usually T2 hyperintense and may show peripheral contrast enhancement. They may show increased glucose avidity on FDGPET and may or may not be positive on isotope bone scans. We suspect that with ever-increasing use of a variety of imaging techniques, particularly in a setting of staging for malignant disease, more such cases will come to light. This diagnosis should be added to the differential diagnosis of sclerotic bone lesions.
Douglass Hanly Moir Pathology, 14 Giffnock Avenue, Macquarie Park, NSW, 2113, Australia, fbonar@dhm.com.au.
S Fiona
SF
Bonar
Geoffrey
G
Watson
Cristian
C
Gragnaniello
Kevin
K
Seex
John
J
Magnussen
John
J
Earwaker
D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008067:Lipoma / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18