hibernoma

Introduction

rare benign adipose tissue neoplasm composed in part of brown fat cells

Microscopic pathology

• variable numbers of polygonal brown fat cells
• small capillary proliferation
• stromal background
• multivacuolated lipoblast-like cells often seen
• variants: myxoid variant (myxoid stroma) spindle cell variant (spindle cells, thick collagen, mast cells)
• mitoses exceptional
• cytologic atypia unusual

Immunophenotype

S100 variable, sometimes strongly positive

Clinical manifestations

• slow growing
• ~10% intramuscular

More general terms

• adipose tissue neoplasm