Hibernoma

Hibernoma, also tumour of brown fat, is an uncommon adipocytic tumour.

Hibernoma
Diagnosis in short
Hibernoma. H&E stain.
LM	large polygonal/oval cells with central & small nucleus; nucleoli typically prominent; cytoplasm multivacuolated, oval, eosinophilic, granular
LM DDx	reaction to silicone implant
Gross	lobulated lesion, light-brown, usually extremities
Site	cervical-supraclavicular, periaortic - both thorax and the abdomen, perirenal; see soft tissue - adipocytic lesions
Clinical history	typically young adults
Prevalence	uncommon
Prognosis	benign
Clin. DDx	Lipoma

General

• Consists of brown fat (present in the infants to generate heat).
• Benign.
• Usually asymptomatic.

Epidemiology:

• Young adults - disappears with age.

Gross

• Well-circumscribed.
• Lobulated and light-brown on sectioning.

Locations:

• Cervical-supraclavicular.
• Periaortic - both thorax and the abdomen.
• Perirenal.

Microscopic

Features:

• Large polygonal/oval cells:
  • Nucleus - central & small.
    • Nucleoli typically prominent.
  • Cytoplasm - multivacuolated, oval, eosinophilic, granular.
• +/-Prominent blood vessels, central.

DDx:

• Reaction to silicone implant.

Images

• 

  Hibernoma - high mag. (WC)

• 

  Hibernoma - intermed mag. (WC)

• 

  Hibernoma - low mag. (WC)

See also

• Adipocytic tumours.
• Lipoma.
• Brown tumour.