Soft tissue
Adipose tissue
Spindle cell / pleomorphic lipoma


Topic Completed: 1 August 2012

Minor changes: 24 April 2020

Copyright: 2002-2020, PathologyOutlines.com, Inc.

PubMed Search: Pleomorphic lipoma / spindle cell lipoma

Vijay Shankar, M.D.
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Cite this page: Shankar V. Spindle cell / pleomorphic lipoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissueadiposepleomorphicgeneral.html. Accessed June 7th, 2020.
Definition / general
  • Subcutaneous tumor of back, shoulder or posterior neck with mature adipocytes, bland spindle cells, floret cells and collagen (Stanford University)
Epidemiology
  • Pleomorphic lipoma and spindle cell lipoma represent a continuum of benign tumors - most tumors show some features of both
  • 70% occur in subcutaneous tissue of shoulder, back and posterior neck
  • 90% men
  • Usually ages 45 - 65 years
  • Usually relatively superficial
  • If deep, some suggest calling well differentiated liposarcoma
Case reports
Treatment
  • Excision
  • Only rare local recurrences, no metastases
Gross description
  • Usually 3 - 5 cm, well circumscribed, yellow-gray-white, firmer than classic lipoma
Gross images

AFIP images

Yellow tumor due to numerous adipocytes

Microscopic (histologic) description
  • Circumscribed tumor with adipocytes that are variable in size at low power
  • Prominent floret giant cells (hyperchromatic, multinucleated, wreath-like nuclei) and small round hyperchromatic cells
  • May have spindle cells similar to spindle cell lipoma
  • No / rare lipoblasts, no prominent vascularity
Microscopic (histologic) images

AFIP images

Numerous pleomorphic and floret cells


Adipocytes, spindle cells and ropy collagen

Pseudoangiomatous
appearance

Spindle cells have
inconspicuous cytoplasm
and small, slender,
uniform nuclei

Spindle cells and collagen with few adipocytes

Cytology description
Positive stains
Negative stains
Electron microscopy description
Molecular / cytogenetics description
  • Structural rearrangements of 13q (Rb) or losses of an entire chromosome 13 are the most common cytogenetic aberrations but 16q deletions and other variations are also possible (Cancer Genomics Proteomics 2018;15:193)
Differential diagnosis
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