Difference between revisions of "Lipoma"

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#redirect [[Adipocytic tumours#Lipoma]]
{{ Infobox diagnosis
| Name      = {{PAGENAME}}
| Image      = Yellow adipose tissue in paraffin section - lipids washed out.jpg
| Width      =
| Caption    = Mature adipose tissue. [[H&E stain]].
| Micro      = mature adipocytes
| Subtypes  =
| LMDDx      = [[liposarcoma]], benign fat
| Stains    =
| IHC        = S-100 +ve
| EM        =
| Molecular  =
| IF        =
| Gross      =
| Grossing  =
| Site      = [[soft tissue]]
| Assdx      =
| Syndromes  =
| Clinicalhx =
| Signs      =
| Symptoms  =
| Prevalence = common
| Bloodwork  =
| Rads      =
| Endoscopy  =
| Prognosis  = benign
| Other      =
| ClinDDx    =
}}
'''Lipoma''' is a benign [[adipocytic tumours|adipocytic tumour]].
 
==General==
*Benign.
*Several variants exist.
**Angiolipoma - one of the (classically) [[painful skin lesions]].
 
==Microscopic==
Features:
*Collection of mature adipocytes.
**Variation of size may be seen -- should prompt a search for lipoblasts.<ref name=pmid8548119>{{Cite journal  | last1 = Mentzel | first1 = T. | last2 = Fletcher | first2 = CD. | title = Lipomatous tumours of soft tissues: an update. | journal = Virchows Arch | volume = 427 | issue = 4 | pages = 353-63 | month =  | year = 1995 | doi =  | PMID = 8548119 }}</ref>
 
Notes:
*Microscopically ''not'' definitely distinguishable from mature clump of fat.
**The lesion must be labeled ''lipoma'' (by the clinican) to be signed-out as such.
 
DDx:
*[[Liposarcoma]] - increased number of blood vessels,<ref name=pmid11685482>{{Cite journal  | last1 = Yang | first1 = YJ. | last2 = Damron | first2 = TA. | last3 = Cohen | first3 = H. | last4 = Hojnowski | first4 = L. | title = Distinction of well-differentiated liposarcoma from lipoma in two patients with multiple well-differentiated fatty masses. | journal = Skeletal Radiol | volume = 30 | issue = 10 | pages = 584-9 | month = Oct | year = 2001 | doi = 10.1007/s002560100395 | PMID = 11685482 }}</ref> esp. chickenwire-like vessels, fibrous septae.
*Benign adipose tissue.
 
Images:
*[http://circ.ahajournals.org/content/113/21/e778/F5.expansion.html Lipoma - cardiac (ahajournals.org)].<ref name=pmid16735681>{{Cite journal  | last1 = Friedberg | first1 = MK. | last2 = Chang | first2 = IL. | last3 = Silverman | first3 = NH. | last4 = Ramamoorthy | first4 = C. | last5 = Chan | first5 = FP. | title = Images in cardiovascular medicine. Near sudden death from cardiac lipoma in an adolescent. | journal = Circulation | volume = 113 | issue = 21 | pages = e778-9 | month = May | year = 2006 | doi = 10.1161/CIRCULATIONAHA.105.589630 | PMID = 16735681 | url = http://circ.ahajournals.org/content/113/21/e778.full }}</ref>
 
===Variants===
====Angiolipoma====
*A [[painful skin lesions|painful skin lesion]].
 
Microscopic:
*Numerous blood vessels present.
*+/-Microthrombi.
 
DDx:
*[[Liposarcoma]].
====Myolipoma====
General:
*May mimic a sarcoma radiologically.<ref>URL: [http://www.webmedcentral.com/article_view/1878 http://www.webmedcentral.com/article_view/1878]. Accessed on: 14 March 2013.</ref>
*Extremely rare.<ref name=pmid15371618>{{Cite journal  | last1 = Murphey | first1 = MD. | last2 = Carroll | first2 = JF. | last3 = Flemming | first3 = DJ. | last4 = Pope | first4 = TL. | last5 = Gannon | first5 = FH. | last6 = Kransdorf | first6 = MJ. | title = From the archives of the AFIP: benign musculoskeletal lipomatous lesions. | journal = Radiographics | volume = 24 | issue = 5 | pages = 1433-66 | month =  | year =  | doi = 10.1148/rg.245045120 | PMID = 15371618 | url = http://radiographics.rsna.org/content/24/5/1433.long }}</ref>
*Usually large ~ 16 cm.<ref name=pmid1703396>{{Cite journal  | last1 = Meis | first1 = JM. | last2 = Enzinger | first2 = FM. | title = Myolipoma of soft tissue. | journal = Am J Surg Pathol | volume = 15 | issue = 2 | pages = 121-5 | month = Feb | year = 1991 | doi =  | PMID = 1703396 }}</ref>
 
Microscopic:<ref name=pmid15371618/>
*Mature adipose tissue.
*Benign smooth muscle - usually ~ 2x amount of fat.
 
Note:
*If skeletal muscle is present consider ''intramuscular lipoma''.<ref> URL: [http://surgpathcriteria.stanford.edu/softfat/lipoma/intramuscular_lipoma.html http://surgpathcriteria.stanford.edu/softfat/lipoma/intramuscular_lipoma.html]. Accessed on: 14 March 2013.</ref>
 
IHC:<ref name=pmid15371618/>
*Actin +ve.
*Desmin +ve.
 
Images:
*[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3168809/figure/F1/ Myolipoma (nih.gov)].<ref name=pmid21927569>{{Cite journal  | last1 = Lee | first1 = YS. | last2 = Park | first2 = SE. | last3 = Lee | first3 = JU. | last4 = Choi | first4 = ES. | title = MRI of a subcutaneous myolipoma in the ankle: a case report. | journal = Korean J Radiol | volume = 12 | issue = 5 | pages = 641-5 | month =  | year =  | doi = 10.3348/kjr.2011.12.5.641 | PMID = 21927569 | PMC = 3168809 }}</ref>
*[http://www.webpathology.com/image.asp?case=431&n=1 Myolipoma (webpathology.com)].
 
===Images===
<gallery>
Image:Yellow_adipose_tissue_in_paraffin_section_-_lipids_washed_out.jpg | Mature fat. (WC)
</gallery>
==Sign out==
<pre>
SUBCUTANEOUS TISSUE ("LIPOMA"), LEFT AXILLA, EXCISION:
- MATURE ADIPOSE TISSUE CONSISTENT WITH LIPOMA.
</pre>
 
<pre>
LESION ("LIPOMA"), SPERMATIC CORD (LATERALITY NOT SPECIFIED), EXCISION:
- MATURE ADIPOSE TISSUE CONSISTENT WITH LIPOMA.
</pre>
 
===Colonic lipoma (clinically suspected)===
<pre>
B. SIGMOID COLON AT 55 CM, BIOPSY:
- COLORECTAL-TYPE MUCOSA WITHIN NORMAL LIMITS WITH A SMALL AMOUNT OF SUBMUCOSAL
  ADIPOSE TISSUE; COMPATIBLE WITH CLINICAL IMPRESSION OF LIPOMA.
</pre>
 
===Mirco===
The sections show mature adipocytes.  There is no increase in vascularity.  No thick fibrous septa are present.
 
==See also==
*[[Adipocytic tumours]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]

Revision as of 01:43, 31 October 2013

Lipoma
Diagnosis in short

Mature adipose tissue. H&E stain.
LM mature adipocytes
LM DDx liposarcoma, benign fat
IHC S-100 +ve
Site soft tissue
Prevalence common
Prognosis benign

Lipoma is a benign adipocytic tumour.

General

Microscopic

Features:

  • Collection of mature adipocytes.
    • Variation of size may be seen -- should prompt a search for lipoblasts.[1]

Notes:

  • Microscopically not definitely distinguishable from mature clump of fat.
    • The lesion must be labeled lipoma (by the clinican) to be signed-out as such.

DDx:

  • Liposarcoma - increased number of blood vessels,[2] esp. chickenwire-like vessels, fibrous septae.
  • Benign adipose tissue.

Images:

Variants

Angiolipoma

Microscopic:

  • Numerous blood vessels present.
  • +/-Microthrombi.

DDx:

Myolipoma

General:

  • May mimic a sarcoma radiologically.[4]
  • Extremely rare.[5]
  • Usually large ~ 16 cm.[6]

Microscopic:[5]

  • Mature adipose tissue.
  • Benign smooth muscle - usually ~ 2x amount of fat.

Note:

  • If skeletal muscle is present consider intramuscular lipoma.[7]

IHC:[5]

  • Actin +ve.
  • Desmin +ve.

Images:

Images

  • Mature fat. (WC)

Sign out

SUBCUTANEOUS TISSUE ("LIPOMA"), LEFT AXILLA, EXCISION: 
- MATURE ADIPOSE TISSUE CONSISTENT WITH LIPOMA.

LESION ("LIPOMA"), SPERMATIC CORD (LATERALITY NOT SPECIFIED), EXCISION: 
- MATURE ADIPOSE TISSUE CONSISTENT WITH LIPOMA.

Colonic lipoma (clinically suspected)

B. SIGMOID COLON AT 55 CM, BIOPSY:
- COLORECTAL-TYPE MUCOSA WITHIN NORMAL LIMITS WITH A SMALL AMOUNT OF SUBMUCOSAL
  ADIPOSE TISSUE; COMPATIBLE WITH CLINICAL IMPRESSION OF LIPOMA.

Mirco

The sections show mature adipocytes. There is no increase in vascularity. No thick fibrous septa are present.

See also

References

  1. ↑ Mentzel, T.; Fletcher, CD. (1995). "Lipomatous tumours of soft tissues: an update.". Virchows Arch 427 (4): 353-63. PMID 8548119.
  2. ↑ Yang, YJ.; Damron, TA.; Cohen, H.; Hojnowski, L. (Oct 2001). "Distinction of well-differentiated liposarcoma from lipoma in two patients with multiple well-differentiated fatty masses.". Skeletal Radiol 30 (10): 584-9. doi:10.1007/s002560100395. PMID 11685482.
  3. ↑ Friedberg, MK.; Chang, IL.; Silverman, NH.; Ramamoorthy, C.; Chan, FP. (May 2006). "Images in cardiovascular medicine. Near sudden death from cardiac lipoma in an adolescent.". Circulation 113 (21): e778-9. doi:10.1161/CIRCULATIONAHA.105.589630. PMID 16735681. http://circ.ahajournals.org/content/113/21/e778.full.
  4. ↑ URL: http://www.webmedcentral.com/article_view/1878. Accessed on: 14 March 2013.
  5. ↑ 5.0 5.1 5.2 Murphey, MD.; Carroll, JF.; Flemming, DJ.; Pope, TL.; Gannon, FH.; Kransdorf, MJ.. "From the archives of the AFIP: benign musculoskeletal lipomatous lesions.". Radiographics 24 (5): 1433-66. doi:10.1148/rg.245045120. PMID 15371618. http://radiographics.rsna.org/content/24/5/1433.long.
  6. ↑ Meis, JM.; Enzinger, FM. (Feb 1991). "Myolipoma of soft tissue.". Am J Surg Pathol 15 (2): 121-5. PMID 1703396.
  7. ↑ URL: http://surgpathcriteria.stanford.edu/softfat/lipoma/intramuscular_lipoma.html. Accessed on: 14 March 2013.
  8. ↑ Lee, YS.; Park, SE.; Lee, JU.; Choi, ES.. "MRI of a subcutaneous myolipoma in the ankle: a case report.". Korean J Radiol 12 (5): 641-5. doi:10.3348/kjr.2011.12.5.641. PMC 3168809. PMID 21927569. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3168809/.
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