Soft tissue

Adipose tissue tumors

Lipoma and variants

Myolipoma



Topic Completed: 1 August 2012

Minor changes: 24 May 2021

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PubMed Search: Myolipoma

Vijay Shankar, M.D.
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Cite this page: Shankar V. Myolipoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissueadiposemyolipoma.html. Accessed October 16th, 2021.
Definition / general
Terminology
  • Called lipoleiomyoma in uterus
  • Note: myelolipoma is tumor with hematopoietic (including myeloid) elements, often in adrenal gland
Epidemiology
  • Very rare tumor of adults in abdomen, retroperitoneum or abdominal wall
  • Other rare sites include eyelid, pericardium, base of tongue
Radiology images

Contributed by Drs. Arno Vanstapel and Raf Sciot, Case #452

CT abdomen frontal

CT abdomen transverse

Case reports
Treatment
  • Excision
  • Does not recur, metastasize or transform
Gross description
  • Often 9 cm or more, completely or partially encapsulated, yellow-white
Gross images

Contributed by Drs. Arno Vanstapel and Raf Sciot, Case #452



Images hosted on other servers:

Fatty tissue with bands and nodules of firm white tissue

Microscopic (histologic) description
  • Mature adipose tissue and mature (well differentiated) smooth muscle in short fascicles (Stanford University)
  • Variable fibrosis and inflammation
  • No floret cells, no thick walled vessels, no necrosis, no mitotic figures
Microscopic (histologic) images

Contributed by Drs. Arno Vanstapel and Raf Sciot, Case #452

5x

10x

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Images hosted on other servers:

Mature fat and smooth muscle fibers

Low magnification view of myolipoma

Smooth muscle fibers are SMA+ (left), desmin+ (right)

Positive stains
Differential diagnosis
Board review style question #1
Which of the following immunohistochemical stains would help distinguish retroperitoneal myolipoma from a well differentiated liposarcoma invading smooth muscle?

A. CDK4
B. HMB45
C. S100
D. Smooth muscle actin
E. Vimentin
Board review style answer #1
A. CDK4

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Reference: Myolipoma
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