Soft tissue
Adipose tissue
Intramuscular lipoma

Author: Charanjeet Singh, M.D. (see Authors page)

Revised: 28 July 2016, last major update June 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Intramuscular lipoma

Cite this page: Intramuscular lipoma. PathologyOutlines.com website. http://pathologyoutlines.com/topic/softtissueadiposeintramuscular.html. Accessed October 20th, 2017.
Definition / general
  • Lipoma that infiltrates within muscle belly
  • Called intermuscular lipoma if between muscle fascicles
Terminology
  • Also called invasive or infiltrative lipoma
  • Not a WHO diagnosis
Sites
  • Intramuscular: affects thigh, trunk, head and neck of middle-aged adults
  • Intermuscular: affects abdominal wall of middle-aged adults; doesn’t recur if completely excised
Clinical features
  • Benign, but 20% recur due to incomplete excision
  • Infiltration may be due to muscular degeneration and endomysial fatty growth secondary to atrophy (BMC Musculoskelet Disord 2004;18:20)
Case reports
Clinical images

Images hosted on other servers:

Tumor of face

Gross description
  • Intramuscular: poorly circumscribed, extends between and around skeletal muscle fibers
Gross images

Images hosted on PathOut servers:

Yellow adipose tissue within skeletal muscle



Images hosted on other servers:

Irregular lobulated tumor without encapsulation

Yellow adipose tissue within skeletal muscle

Microscopic (histologic) description
  • Mature lipocytes that infiltrate skeletal muscle
  • No atypia, no mitotic figures
Microscopic (histologic) images

Images hosted on PathOut servers:

Adipocytes and atrophic muscle



Images hosted on other servers:

Prominent muscular atrophy

Adipocytes and atrophic muscle

Intramuscular lipoma

Differential diagnosis