Hibernoma: imaging characteristics of a rare benign soft tissue tumor

Abstract

Hibernoma is a rare benign soft tissue tumor of brown fat. Awareness of the MR imaging appearances of this lesion may allow for improved preoperative diagnosis or at least inclusion of hibernoma as a possible benign differential diagnosis prior to surgery.

Hibernoma: Intense Uptake on F18-FDG PET/CT

“…The CT, MRI, ultrasonography, angiography, and F18-FDG PET imaging of hibernomas reflect their histopathology and the relative amount of brown fat and white fat [1,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The masses are often heterogenous on MRI and CT with characteristics similar but not identical to those of fat.…”

“…Hibernomas demonstrate well-defined margins on CT and attenuation between fat and skeletal muscle, depending on the tumor's lipid content. Multiple vessels are often seen coursing through the mass, with enhancement of soft tissue components after the administration of intravenous contrast medium [1,8,9]. MRI also reflects the tumor's lipid content; some investigators note a correlation between the histological subtype and MRI appearance.…”

“…Non-lipoma-like hibernomas were isointense to mildly hypointense to fat on T2-weighted images, and moderately to markedly inhomogeneous on postcontrast T1-weighted images, showing either diffuse prominent enhancement or intense enhancement in vessels or septa [17]. MR angiography may demonstrate marked vascularity [8]. Saito et al [19] reported that the signal intensity of a hibernoma was not suppressed on a T2-weighted fat suppression image.…”

Functional Diagnosis of Hibernoma by FDG Imaging Under Propranolol Treatment: A Case Report

“…In fact, high FDG retention can be observed in benign lesion originating from tissues characterized by high glycolytic rate. This finding frequently occurs in benign neoplasms originating from brown fat, defined as "hibernomas", whose low prevalence (1.6% of benign lipomatous tumors) often prevents a correct identification [2][3][4]. Actually, these lesions are most frequently observed in areas occupied by brown persists after fetal life (mediastinum, retroperitoneum, as well as paravertebral, supra-clavear and laterocervical spaces) [5].…”

Expert’s comment concerning Grand Rounds case entitled “Paraspinal hibernoma: Grand Round presentation of a rare benign adipocytic tumor” by S. Ghailane et al. (Eur Spine J; 2017: DOI 10.1007/s00586-017-5124-5)

“…Anderson [2] and Kransdorf [3] have described the imaging characteristics of hibernoma. MRI characteristics are of high signal intensity on T1 sequences, very high intensity on T2, heterogeneous fat suppression and diffuse gadolinium enhancement.…”