spindle cell lipoma

Introduction

part of histologic spectrum of spindle cell lipoma & pleomorphic lipoma.

Epidemiology

• older men, median age over 50 yrs.
• predominantly posterior neck & shoulder
• face, forehead, scalp, buccal-perioral area, upper arm less common; lower extremity rare

Pathology

oval/discoid yellow/gray/white mass, firmer texture than ordinary lipomas

Microscopic pathology

• variable numbers of adipocytes
• bland mitotically inactive spindle cells
• thick rope like collagen bundles
• often large numbers of mast cells
• may show myxoid stromal change or slit like spaces resembling vascular slits

Immunophenotype

CD34 strongly positive S100 may rarely be positive

Genetics

• frequently hypodiploid
• monosomy/partial monosomy 13/16
• breakpoint chromosome 16q13 with loss of 16q13-qter
• chromosome 13q12 and 13q14-q22 losses

Clinical manifestations

• asymptomatic, circumscribed, mobile dermal or subcutaneous mass
• long history
• usually single lesions

Management

• benign behavior
• conservative local excision

More general terms

• adipose tissue neoplasm