Difference between revisions of "Lipoma"

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#redirect [[Adipocytic tumours#Lipoma]]
{{ Infobox diagnosis
| Name      = {{PAGENAME}}
| Image      = Lipoma -- intermed mag.jpg
| Width      =
| Caption    = Mature adipose tissue (lipoma). [[H&E stain]].
| Synonyms  = [[steatoma]] (old term, ambiguous)
| Micro      = mature adipocytes
| Subtypes  =
| LMDDx      = [[liposarcoma]], benign fat
| Stains    =
| IHC        = S-100 +ve
| EM        =
| Molecular  = MDM2/CDK4 amplification absent
| IF        =
| Gross      = soft yellow tissue - typically with a thin capsule and lobulated
| Grossing  =
| Site      = [[soft tissue]]
| Assdx      =
| Syndromes  =
| Clinicalhx =
| Signs      = [[pillow sign]] (endoscopy)
| Symptoms  =
| Prevalence = common
| Bloodwork  =
| Rads      =
| Endoscopy  = smooth yellow coloured submucosal lesion
| Prognosis  = benign
| Other      =
| ClinDDx    =
| Tx        = surgical removal or follow-up
}}
'''Lipoma''' is a benign [[adipocytic tumours|adipocytic tumour]].
 
==General==
*Benign.
*Several variants exist.
**Angiolipoma - one of the (classically) [[painful skin lesions]].
*May be seen in association with MERRF syndrome (myoclonic epilepsy with ragged-red fibres).<ref name=pmid21865105>{{Cite journal  | last1 = Jones | first1 = AP. | last2 = Lewis | first2 = CJ. | last3 = Dildey | first3 = P. | last4 = Hide | first4 = G. | last5 = Ragbir | first5 = M. | title = Lipoma or liposarcoma? A cautionary case report. | journal = J Plast Reconstr Aesthet Surg | volume = 65 | issue = 1 | pages = e11-4 | month = Jan | year = 2012 | doi = 10.1016/j.bjps.2011.08.004 | PMID = 21865105 }}</ref>
*May be seen in the context of ''[[Madelung's disease]]''.<ref name=pmid29129710>{{Cite journal  | last1 = Mayo Yáñez | first1 = M. | last2 = González Poggioli | first2 = N. | last3 = Álvarez-Buylla Blanco | first3 = M. | last4 = Herranz González-Botas | first4 = J. | title = Benign symmetric lipomatosis with lingual involvement: Case report and literature review. | journal = J Stomatol Oral Maxillofac Surg | volume =  | issue =  | pages =  | month = Nov | year = 2017 | doi = 10.1016/j.jormas.2017.11.006 | PMID = 29129710 }}</ref>
 
==Gross==
*Soft yellow tissue - typically lobulated and with a very thin capsule.
 
Note:
*May be quite large ~10 cm.
*Thigh lesions are more likely to the malignant than other sites.<ref name=pmid27020493/>
 
==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: Lipoma -- intermed mag.jpg | Lipoma - intermed. mag.
Image: Lipoma -- high mag.jpg | Lipoma - high mag.
Image:Yellow_adipose_tissue_in_paraffin_section_-_lipids_washed_out.jpg | Mature fat. (WC)
</gallery>
 
==Molecular==
*MDM2/CDK4 gene amplification absent.
**Testing suggested in lesions greater than 10 cm, thigh lesions and lesions with cytologic atypia.<ref name=pmid27020493>{{Cite journal  | last1 = Wong | first1 = DD. | last2 = Low | first2 = IC. | last3 = Peverall | first3 = J. | last4 = Robbins | first4 = PD. | last5 = Spagnolo | first5 = DV. | last6 = Nairn | first6 = R. | last7 = Carey-Smith | first7 = RL. | last8 = Wood | first8 = D. | title = MDM2/CDK4 gene amplification in large/deep-seated 'lipomas': incidence, predictors and clinical significance. | journal = Pathology | volume = 48 | issue = 3 | pages = 203-9 | month = Apr | year = 2016 | doi = 10.1016/j.pathol.2016.02.007 | PMID = 27020493 }}</ref>
 
==Sign out==
===Large lesion looks like lipoma===
Bland lesions may be well-differentiated liposarcoma.<ref>URL: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3422587/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3422587/]. Accessed on: 3 June 2017.</ref> Lesions >10 cm should be of concern.
<pre>
Lesion (Submitted as "Lipoma"), Right Neck, Excision:
- Bland appearing adipose tissue suggestive of lipoma, see comment.
- One benign lymph node.
 
Comment:
Due to the size of the lesion, the case will be sent to a soft tissue pathologist for review.
</pre>
 
===Block letter===
<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:Adipocytic tumours]]

Latest revision as of 20:56, 10 December 2018

Lipoma
Diagnosis in short

Mature adipose tissue (lipoma). H&E stain.
Synonyms steatoma (old term, ambiguous)
LM mature adipocytes
LM DDx liposarcoma, benign fat
IHC S-100 +ve
Molecular MDM2/CDK4 amplification absent
Gross soft yellow tissue - typically with a thin capsule and lobulated
Site soft tissue
Signs pillow sign (endoscopy)
Prevalence common
Endoscopy smooth yellow coloured submucosal lesion
Prognosis benign
Treatment surgical removal or follow-up

Lipoma is a benign adipocytic tumour.

General

  • Benign.
  • Several variants exist.
  • May be seen in association with MERRF syndrome (myoclonic epilepsy with ragged-red fibres).[1]
  • May be seen in the context of Madelung's disease.[2]

Gross

  • Soft yellow tissue - typically lobulated and with a very thin capsule.

Note:

  • May be quite large ~10 cm.
  • Thigh lesions are more likely to the malignant than other sites.[3]

Microscopic

Features:

  • Collection of mature adipocytes.
    • Variation of size may be seen -- should prompt a search for lipoblasts.[4]

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,[5] 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.[7]
  • Extremely rare.[8]
  • Usually large ~ 16 cm.[9]

Microscopic:[8]

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

Note:

  • If skeletal muscle is present consider intramuscular lipoma.[10]

IHC:[8]

  • Actin +ve.
  • Desmin +ve.

Images:

Images

  • Lipoma - intermed. mag.

  • Lipoma - high mag.

  • Mature fat. (WC)

Molecular

  • MDM2/CDK4 gene amplification absent.
    • Testing suggested in lesions greater than 10 cm, thigh lesions and lesions with cytologic atypia.[3]

Sign out

Large lesion looks like lipoma

Bland lesions may be well-differentiated liposarcoma.[12] Lesions >10 cm should be of concern. 

 
Lesion (Submitted as "Lipoma"), Right Neck, Excision:
	- Bland appearing adipose tissue suggestive of lipoma, see comment.
	- One benign lymph node.

Comment:
Due to the size of the lesion, the case will be sent to a soft tissue pathologist for review.

Block letter

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. ↑ Jones, AP.; Lewis, CJ.; Dildey, P.; Hide, G.; Ragbir, M. (Jan 2012). "Lipoma or liposarcoma? A cautionary case report.". J Plast Reconstr Aesthet Surg 65 (1): e11-4. doi:10.1016/j.bjps.2011.08.004. PMID 21865105.
  2. ↑ Mayo Yáñez, M.; González Poggioli, N.; Álvarez-Buylla Blanco, M.; Herranz González-Botas, J. (Nov 2017). "Benign symmetric lipomatosis with lingual involvement: Case report and literature review.". J Stomatol Oral Maxillofac Surg. doi:10.1016/j.jormas.2017.11.006. PMID 29129710.
  3. ↑ 3.0 3.1 Wong, DD.; Low, IC.; Peverall, J.; Robbins, PD.; Spagnolo, DV.; Nairn, R.; Carey-Smith, RL.; Wood, D. (Apr 2016). "MDM2/CDK4 gene amplification in large/deep-seated 'lipomas': incidence, predictors and clinical significance.". Pathology 48 (3): 203-9. doi:10.1016/j.pathol.2016.02.007. PMID 27020493.
  4. ↑ Mentzel, T.; Fletcher, CD. (1995). "Lipomatous tumours of soft tissues: an update.". Virchows Arch 427 (4): 353-63. PMID 8548119.
  5. ↑ 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.
  6. ↑ 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.
  7. ↑ URL: http://www.webmedcentral.com/article_view/1878. Accessed on: 14 March 2013.
  8. ↑ 8.0 8.1 8.2 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.
  9. ↑ Meis, JM.; Enzinger, FM. (Feb 1991). "Myolipoma of soft tissue.". Am J Surg Pathol 15 (2): 121-5. PMID 1703396.
  10. ↑ URL: http://surgpathcriteria.stanford.edu/softfat/lipoma/intramuscular_lipoma.html. Accessed on: 14 March 2013.
  11. ↑ 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/.
  12. ↑ URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3422587/. Accessed on: 3 June 2017.
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