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spindle cell lipoma

Tuesday 11 October 2005

spindle cell/pleomorphic lipoma; spindle cell lipoma/pleomorphic lipoma; fusiform cell lipoma; spindle cell/pleomorphic lipoma


- spindle cell tumor / fusiform cell tumor
- Benign, superficial. Male predilection (>50 yo)
- Mature adipocytes, spindle+mast cells, myxoid stroma, ropey collagen
- If "Floret" cells: Pleomorphic lipoma
- possiblke lipoblasts
- IHC: CD34+ Desmin/SMA-
- deletion of RB1(13q14)

- Cellular variants of spindle cell lipoma/ Pleomorphic lipoma:



Digital cases

- JRC:2293 : spindle cell lipoma.
- JRC:14822 : spindle cell lipoma.


- myxoid tumor
- spindle cell tumor
- CD34+++, S100-


Mammary-type myofibroblastoma and cellular angiofibroma show overlapping histologic features and similar chromosomal losses, suggesting a possible relationship among these tumor types. There is a pathogenetic relationship among this group of tumors.

Differential diagnosis

- spindle cell tumors / fusiform cell tumors
- adipocytic tumors

  • lipomas


Consistent rearrangements of chromosomes 13q and 16q have been identified in spindle cell and pleomorphic lipomas by cytogenetics.

The tumor suppressor gene RB1, encoding the retinoblastoma (Rb) protein, is located at 13q14, within a minimally deleted region in spindle cell lipoma.

- partial monosomy 16q

  • loss of material from the region 16q13-qter

- monosomy 13 or partial monosomy 13q


- Loss of retinoblastoma protein expression in spindle cell/pleomorphic lipomas and cytogenetically related tumors: an immunohistochemical study with diagnostic implications. Chen BJ, Mariño-Enríquez A, Fletcher CD, Hornick JL. Am J Surg Pathol. 2012 Aug;36(8):1119-28. PMID: 22790852