A 23-year-old female presented with headache, palpitation, and hypertensive spells. There was no similar family history. Twenty-four (24) hour urine testing showed elevated normetanephrine level with normal metanephrines [metanephrines 123 mcg/24 hrs (74-297); normetanephrines 5321.16 mcg/24 hrs (73-808)]. A biochemical diagnosis of normetanephrine-secreting pheochromocytoma was made. Considering the age and urine reports, a functional scan was ordered. Imaging with 18-FDG PET CT was done which showed uptake indicative of a large left adrenal mass, as well as uptake in the mediastinal, abdominopelvic, lymph nodes and metabolically active mesenteric, peritoneal and omental thickness. This suggested a left adrenal pheochromocytoma with the possibility of an associated lymphoproliferative disorder or active lesions in brown fat. To describe these extra-adrenal lesions, a Ga-68 This work DOTANOC PET CT was obtained which showed a diffuse somatostatin receptor-expressing large soft tissue mass lesion in the left adrenal likely to be pheochromocytoma without any other lesion elsewhere in the whole body survey. This depicts the confusion created by the metabolically active brown adipose tissue (BAT) in the FDG PET scan. Brown fat is involved in non-shivering thermogenesis and is typically located in the cervical, supraclavicular, mediastinal, and abdominal regions. High uptake in the BAT can make interpretation of the FDG PET report difficult and misleading. Some precautions like avoidance of cold and beta blockers can minimize BAT uptake in FDGPET scans.
Adipose Tissue, Brown ; Pheochromocytoma

Rats ; Animals ; Adipose Tissue, Brown/physiology* ; Adipose Tissue

Brown adipose tissue (BAT) is regarded as a key target for developing interventions to prevent and treat obesity and age-related diseases. In addition, uncoupling pro tein 1 (UCP1)
Adipocytes ; Adipose Tissue ; Adipose Tissue, Brown ; Adipose Tissue, White ; Atrophy ; Eating ; Humans ; Middle Aged ; Obesity ; Thermogenesis

brown adipose tissue (BAT) from white adipose tissue (WAT) in rats using spectral computed tomography (CT) with histological validation.MATERIALS AND METHODS: A lipid-containing phantom (lipid fractions from 0% to 100%) was imaged with spectral CT. An in vivo, non-enhanced spectral CT scan was performed on 24 rats, and fat concentrations of BAT and WAT were measured. The rats were randomized to receive intraperitoneal treatment with norepinephrine (NE) (n = 12) or saline (n = 12). Non-enhanced and enhanced spectral CT scans were performed after treatment to measure the elevation of iodine in BAT and WAT. The BAT/aorta and WAT/aorta ratios were calculated and compared, after which isolated BAT and WAT samples were subjected to histological and uncoupling protein 1 (UCP1) analyses.RESULTS: The ex-vivo phantom study showed excellent linear fit between measured fat concentration and the known gravimetric reference standard (r² = 0.996). In vivo, BAT had significantly lower fat concentration than WAT (p < 0.001). Compared to the saline group, the iodine concentration of BAT increased significantly (p < 0.001) after injection of NE, while the iodine concentration of WAT only changed slightly. The BAT/aorta ratio also increased significantly after exposure to NE compared to the saline group (p < 0.001). Histological and UCP1 expression analyses supported the spectral CT imaging results.CONCLUSION: The study consolidates spectral CT as a new approach for non-invasive imaging of BAT and WAT. Quantitative analyses of BAT and WAT by spectral CT revealed different characteristics and pharmacologic activations in the two types of adipose tissue.]]>
Adipose Tissue ; Adipose Tissue, Brown ; Adipose Tissue, White ; Animals ; Iodine ; Norepinephrine ; Rats ; Tomography, X-Ray Computed

Hibernoma is a rare subcutaneous neoplasm resembling the brown fat of the hibernating animal. It is usually found in the interscapular, cervical or axillary regions. We report a case of this rare tumor which developed on the occeipital scalp of a 42-year-old woman.
Adipose Tissue, Brown ; Adult ; Animals ; Female ; Humans ; Lipoma* ; Scalp*

Hibernoma is a rare hypervascular benign soft tissue tumor arising from residual fetal brown fat. Awareness of the MR imaging appearances of this lesion may allow at least inclusion of hibernoma in the possible differential diagnosis prior to surgery.
Adipose Tissue, Brown ; Axilla ; Diagnosis, Differential ; Lipoma* ; Magnetic Resonance Imaging*

Brown adipose tissue contributes to energy balance in humans by generating heat via the mitochondrial uncoupling of lipid oxidation. Currently it is believed that brown adipose has two origins: Myf5-negative progenitor (its source is same as that of white adipocyte) and Myf5-positive progenitor (its source is same as myocyte). Due to the different origins of brown adipocytes, they may be formed via multiple pathways which include the main pathway (by which Myf5-positive progenitors differentiate into brown adipocytes that distribute in classical locations) and alternative pathway (by which Myf5-negative progenitors differentiate into brown adipocytes that distribute in white adipose tissue).
Adipocytes ; cytology ; Adipose Tissue, Brown ; cytology ; physiology ; Humans

The induction of brown-like adipocyte development in white adipose tissue (WAT) confers numerous metabolic benefits by decreasing adiposity and increasing energy expenditure. Therefore, WAT browning has gained considerable attention for its potential to reverse obesity and its associated co-morbidities. However, this perspective has been tainted by recent studies identifying the detrimental effects of inducing WAT browning. This review aims to highlight the adverse outcomes of both overactive and underactive browning activity, the harmful side effects of browning agents, as well as the molecular brake-switch system that has been proposed to regulate this process. Developing novel strategies that both sustain the metabolic improvements of WAT browning and attenuate the related adverse side effects is therefore essential for unlocking the therapeutic potential of browning agents in the treatment of metabolic diseases.
Adipocytes, Beige ; cytology ; Adipose Tissue, Brown ; cytology ; metabolism ; Adipose Tissue, White ; cytology ; Aging ; metabolism ; Animals ; Humans

Hibernoma is a rare, benign soft tissue tumor that is derived from the remnants of fetal brown tissue. The term hibernoma was proposed in 1914 by Cery because of its morphologic similarity to the cel s of the so-called hibernating gland of animals. The most common site of hibernomas is the subcutaneous tissue of the back, especially the interscapular area. These tumors are considered benign and malignant transformation has not been reported. We experienced a case of hibernoma, 60-year-old woman had suffered from the palpable mass without pain or tenderness on posterolateral lower chest wall, left. The tumor was extirpated under the impression of angiolipoma, but was confirmed hibernoma. She was discharged without complication.
Adipose Tissue, Brown ; Angiolipoma ; Animals ; Female ; Humans ; Lipoma* ; Middle Aged ; Subcutaneous Tissue ; Thoracic Wall* ; Thorax*

Brown adipose generates heat via oxidation of fatty acids by a mitochondrial uncoupling protein 1 (UCP1)-dependent process. In addition, a subpopulation of cells within subcutaneous white adipose tissue, known as beige adipocytes, also plays a role in thermogenesis. The biogenesis of beige adipocytes is induced by thermogenic signals, such as chronic cold exposure. Recently, it has been reported that eosinophils, type 2 cytokines of IL-4/13, and alternatively activated macrophages control the thermogenic cycle of beige adipocytes. Alternatively, activated macrophages induce UCP1+ beige adipocytes through secretion of catecholamines. These results define the role of type 2 immune responses in the regulation of energy homeostasis.
Adipocytes ; Adipose Tissue, Brown ; Adipose Tissue, White ; Organelle Biogenesis* ; Catecholamines ; Cytokines ; Eosinophils* ; Fatty Acids ; Homeostasis ; Hot Temperature ; Macrophages* ; Thermogenesis