Hibernoma: a rare benign soft tissue tumour resembling liposarcoma

Hibernoma is a rare benign soft tissue tumour that can mimic a liposarcoma on radiographic imaging. Our case series review illustrates the clinical presentation and radiographic appearances of four patients with histologically confirmed hibernoma. Hibernoma is usually hypointense relative to subcutaneous fat on T (1) weighted MRI and demonstrates partial fat suppression on fat-saturated sequences. Large intratumoral vessels likely support the diagnosis of hibernoma but are not invariably present. Fludeoxyglucose avidity on PET scan is not beneficial in distinguishing hibernoma from soft tissue malignancy because of its inherent, metabolically active property. Owing to the radiographic heterogeneity of hibernoma, it is currently not possible to diagnose hibernoma based on imaging characteristics alone. Given the excellent prognosis of hibernoma with marginal excision alone, an appreciation of the radiographic features is helpful in the appropriate pre-operative workup of soft tissue tumours.