Cervical Hibernoma Demonstrating Uptake on Tc-99m Lymphoscintigraphy

Abstract

A hibernoma is an uncommon, benign tumor composed of brown adipose tissue. It is a rare but documented cause of neck masses. Hibernomas may be first diagnosed not by clinical examination, but incidentally through radiologic tests assessing the metabolic activity of certain tissues. These tumors are by definition benign entities but, given their propensity for growth over time, they require complete extirpation to prevent recurrence. Different radiologic modalities have been used to evaluate hibernomas, including computed tomography scan, magnetic resonance imaging, fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography, and angiography. It is rare for a hibernoma to be discovered through Tc-99m lymphoscintigraphy.

Have you ever heard of hibernoma? A rare but important pitfall in FDG-PET/CT

“…There is no literature on SUV reduction in hibernomas after beta-blocker treatment as it is described for brown fat by Agrawal et al in 2009 (1). Even though without clinical impact, incidental uptake of 99m Tc tetrofosmin, during 99m Tc lymphoscintigraphy and bone scintigraphy has been observed in hibernomas (5,12,15,17).…”

Laryngeal hibernoma: Case series of a rare tumor

“…Positron emission tomography using 18F‐fluoro‐2‐deoxy‐d‐glucose shows active uptake with standardized uptake values (SUVs) between 11 and 26, which is much higher than the SUVs reported in published studies of lipoma (SUV of <2) and liposarcoma (SUV from 2 to 9) . Tc‐99m lymphoscintigraphy also shows uptake given the high mitochondrial density in hibernomas . The heterogeneous, hypervascular features of hibernoma on imaging make these tumors difficult to distinguish from other hypervascular lipid‐containing soft tissue tumors, including malignant liposarcoma, fibrosarcoma, malignant fibrous histiocytoma, and rhabdomyosarcoma, or benign angiolipoma, lipoblastoma, atypical lipoma, neurofibroma, elastofibroma, and hemangioma …”

“…Internal complexity may be visible, with the presence of small vessels and fibrous bands, distinguishing hibernoma from a simple lipoma . Ultrasound is nonspecific, with reports of both homogeneous and heterogeneous, hyperechoic, and hypoechoic appearances. Doppler and angiography reveal hypervascularity .…”

False-Positive Diagnosis of Metastasis on Positron Emission Tomography–Computed Tomography Imaging Due to Hibernoma

“…A second report 6 described a glucose-avid intramuscular hibernoma of the lateral chest wall found in a patient 6 months postlobectomy for lung adenocarcinoma. Another report 7 described a glucose-avid hibernoma in the neck found during staging of infiltrating ductal carcinoma of breast. Synchronous presentation of two different rare adipocytic tumors in our patient is perplexing and proved a diagnostic challenge.…”