Hibernoma: a case report demonstrating usefulness of MR angiography in characterizing the tumor

Abstract

Hibernoma is a rare, benign soft-tissue tumor composed of brown fat. In the past, there has been an extensive discussion of the CT attenuation and MRI signal characteristics of hibernomas. However, recent reports have focused upon the tumor vascularity of hibernomas. We describe the only case in the literature which utilizes state of the art contrast enhanced MR angiography to clearly characterize the surface and intratumoral vessels to help confirm the diagnosis of a hibernoma and aid in the preoperative planning.

Imaging of hibernomas: A retrospective study on twelve cases

“…The heterogeneous lesion on T1WSE remained heterogeneously hyperintense on T2WSE images as well. Finally, like in most cases [5-7,13-17], STIR and T2 fat sat sequences failed to achieve full suppression of the examined hibernomas and displayed the most heterogeneous patterns. Gadolinium enhancement, either heterogeneous or homogeneous, is usually present in hibernomas [5,7,11-18]; even though Cook M et al [8] and Lee J [6] et al did not report any significant gadolinium uptake in their cases.…”

“…Lipomas present as homogeneous fatty masses with few scattered internal septa and no signs of enhancement [6]. Angiolipomas and hemangiomas can be distinguished in terms of different morphology of internal vasculature [13,16,17]. Several studies [4,16-18] stress the importance of large branching intratumoral vessels with early contrast enhancement and AV shunting in the differential diagnosis of hibernomas.…”

Interscapular hibernoma—Case report and literature review

“…The vascular structure in hibernoma has received attention in recent reports. In addition to heterogenous enhancement after contrast administration, large feeding surface vessels have been found on Doppler ultrasound [12], and increased T1 signal intensity and large intratumor vessels indicating a diagnosis of hibernoma have been suggested in some reports [12–14]. By using recent advances in MR time‐resolved contrast imaging, these large vessels clearly demonstrated arteriovenous shunting [14].…”

Hibernoma of the thigh: a lipoma-like variant rare tumour mimicking soft tissue sarcoma

“…However, brown fat is also found in more than 50 non-hibernating animal species, as well as in man 3. It is abundant in newborn humans and gradually decreases in quantity during life compromising less than 0.1% of total body weight by the age of 70 years 3 6 12. Unlike white adipose, the function of brown adipose is thermogenesis 4…”

“…Angiolipoma and haemangioma can be distinguished in terms of different morphology of internal vasculature 10–12. Some studies stress the significance of large branching intratumoral vessels with early contrast enhancement and arterio-venous shunting in the differential diagnosis of hibernomas 6 11 12. However, these features are not always present, although fine enhancing strands may be seen 9.…”