Soft tissue
Adipose tissue
Intramuscular lipoma



Topic Completed: 1 June 2012

Revised: 17 May 2019

Copyright: 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Intramuscular lipoma

Page views in 2018: 4,822
Page views in 2019 to date: 4,357
Cite this page: Singh C. Intramuscular lipoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissueadiposeintramuscular.html. Accessed September 22nd, 2019.
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 server:

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 server:

Adipocytes and atrophic muscle



Images hosted on other servers:

Prominent muscular atrophy

Adipocytes and atrophic muscle

Intramuscular lipoma

Differential diagnosis
Back to top