Lipomatous tumor: Difference between revisions

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==Gross processing==

*Perform consecutive '''slicing''' of the entire specimen.

*Look for signs of '''liposarcoma''': Mainly by firm volumes.<ref>{{Lilla utskärningen}}</ref> Color varies from yellow to white (and firm) depending on the proportion of adipocytic, fibrous and/or myxoid content.<ref name=Mavrogenis2013>{{cite web|url=http://atlasgeneticsoncology.org/Tumors/WellDiffLiposarcomaID5167.html|title=Soft Tissues: Well-differentiated liposarcoma|author=Andreas F Mavrogenis, Panayiotis J Papagelopoulos|date=2013-02-01|website=Atlas of Genetics and Cytogenetics in Oncology and Haematology}}</ref> Areas of fat necrosis are common in larger lesions. Rarely, infiltrative growth is seen.<ref name=Mavrogenis2013/>

*Submit slices from any suspicious parts, or at least one representative slice from the specimen.

*'''Submit''' slices from any suspicious parts, or at least one representative slice from the specimen.<ref>{{NU Hospital Group}}</ref> {{Moderate-begin}}A more comprehensive practice is to submit 1 section per centimeter, and 2 sections per cassette.<ref>{{cite web|url=https://voices.uchicago.edu/grosspathology/bone-soft-tissue/lipoma/|title=Lipoma|website=Gross Pathology Manual - By The University of Chicago Department of Pathology|accessdate=2020-08-26}}</ref>{{Moderate-end}}

File:Lipoma gross.jpg|thumb|Cross-section of '''lipoma'''. Homogenous texture.

File:Gross pathology of undifferentiated liposarcoma.jpg|'''Liposarcoma''': Tumor section reveals brownish-yellowish areas, hemorrhagic and calcific zones.

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Example:

{|class="wikitable"

| Mass weighing 121 grams and measuring 10 x 6,5 x 3,5 cm. ~~Homogenous~~ yellow color~~. No~~ hemorrhage or necrosis.

| Mass {{Comprehensive-begin}}weighing 121 grams{{Comprehensive-end}} and measuring 10 x 6,5 x 3,5 cm. {{Comprehensive-begin}}The surgical margin is intact.{{Comprehensive-end}} Cut sections show homogenous yellow color, with no hemorrhage or necrosis. {{Comprehensive-begin}}The specimen is serially sectioned, and representative sections are submitted for microscopic examination in __ cassettes.{{Comprehensive-end}}

|}

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==Microscopic evaluation==

File:Histopathology of lipoma.jpg|'''Lipoma''': lobules of mature white adipose tissue divided by delicate and inconspicuous fibrous septa containing thin-walled capillary-sized vessels.

File:Histopathology of lipoma.jpg|'''Lipoma''': lobules of mature white adipose tissue divided by delicate and inconspicuous fibrous septa containing thin-walled capillary-sized vessels. Still, look close at the fibrous septa:

File:Histopathology of a fibrolipoma.jpg|'''Fibrolipoma''' is a lipoma with focal areas of large amounts of fibrous tissue. A '''sclerotic lipoma''' is one step further: a predominantly fibrous lesion with focal areas of fat.<ref>{{cite web|url=http://surgpathcriteria.stanford.edu/softfat/lipoma/fibrolipoma.html|title=Lipoma Variant: Fibrolipoma|website=[[Stanford University School of Medicine]]|accessdate=2020-02-10}}</ref> If unsure of degree of fibrosis: Simply report as lipoma.

File:Histopathology of an atypical lipomatous tumor or well-differentiated liposarcoma, lipoma-like subtype.jpg|An '''atypical lipomatous tumor''' (also termed '''well-differentiated liposarcoma'''), lipoma-like subtype. At low magnification, the majority of the tumor essentially has the look of benign mature adipocytes (except for mildly increased variation in lipid droplet sizes), but high magnification of a fibrous band shows spindle cells with enlarged, hyperchromatic nuclei. Another clue for liposarcoma is a higher variability of lipid droplet sizes.

File:Histopathology of a fibrolipoma.jpg|'''Fibrolipoma''' is a lipoma with focal areas of large amounts of fibrous tissue. A '''sclerotic lipoma''' is one step further: a predominantly fibrous lesion with focal areas of fat.<ref>{{cite web|url=http://surgpathcriteria.stanford.edu/softfat/lipoma/fibrolipoma.html|title=Lipoma Variant: Fibrolipoma|website=Stanford University School of Medicine|accessdate=2020-02-10}}</ref> If unsure of degree of fibrosis: Simply report as lipoma.

File:Histopathology of angiolipoma.jpg|'''Angiolipoma''' is a lipoma with abundant capillaries, with hyaline or fibrin (pictured) thrombi.<ref>{{cite web|url=http://www.pathologyoutlines.com/topic/softtissueadiposeangiolipoma.html|title=Soft tissue - Adipose tissue tumors - Lipoma and variants - Angiolipoma|author=Vijay Shankar|website=Pathology Outlines}} Topic Completed: 1 August 2012. Minor changes: 20 March 2019</ref>

File:Histopathology of liposarcoma, annotated.jpg|Main features of '''liposarcoma''':<ref name=PathologyOutlines-Liposarcoma>{{cite web|url=https://www.pathologyoutlines.com/topic/softtissuewdliposarcoma.html%7Ctitle=Liposarcoma|author=Michael R. Clay, M.D.|website=PathologyOutlines|title=Liposarcoma}} Topic Completed: 1 November 2017. Minor changes: 11 May 2021</ref> - Spindle cells with enlarged, hyperchromatic nuclei. - Apparently univacuolated adipocytes (may look normal). - [[Lipoblast]]s, but is neither necessary nor sufficient for diagnosis.

File:Lipoblast features, annotated.png|Lipoblast features

File:Myxoid liposarcoma (16105753363).jpg|'''Myxoid liposarcoma''': Hypercellular solid sheets of cells lying back to back, with round cells or primitive cytomorphology.<ref>{{cite web|url=http://www.pathologyoutlines.com/topic/softtissuemyxoidliposarcoma.html|title=Soft tissue - Adipose tissue - Myxoid liposarcoma|author=Michael R. Clay|website=PathologyOutlines}} Topic Completed: 1 January 2018. Revised: 20 March 2019</ref>

</gallery>

A '''pedunculated''' lipomatous skin tumor may be a '''pedunculated lipofibroma''':

File:Pedunculated lipofibroma, gross pathology.jpg|Pedunculated lipofibroma, gross pathology

File:Pedunculated lipofibroma (intermediate magnification).jpg|Histopathology, showing thin rim of epidermis, and dermal lipocytes without capsule.

</gallery>

For atypical cases and as a non-subspecialist in soft tissue pathology, generally seek '''expert opinion''', including further workup.

===Microscopy/Histopathology report===

For lipomas: Absence of signs of malignancy.

For lipomas: {{Moderate-begin}}Absence of signs of malignancy.{{Moderate-end}}

{|class="wikitable"

| [[File:Histopathology of lipoma.jpg|190px|left]]

| [[File:Histopathology of lipoma.jpg|190px|left]] {{Moderate-begin}}Chest wall, left lateral, excision:{{Moderate-end}}

Tissue composed of univacuolar fat cells and delicate and inconspicuous fibrous septa. ~~No evidence of malignancy.~~

*Lipoma.

*{{Moderate-begin}}Negative for malignancy{{Moderate-end}}

{{Comprehensive-begin}}Microscopic description: Tissue composed of univacuolar fat cells and delicate and inconspicuous fibrous septa.{{Comprehensive-end}}

|}

@@ Line 6: / Line 6: @@
 {{Fixation - standard}}
 {{Fixation - general notes}}
+{{Comprehensiveness}}
 ==Gross processing==
 *Perform consecutive '''slicing''' of the entire specimen.
 *Look for signs of '''liposarcoma''': Mainly by firm volumes.<ref>{{Lilla utskärningen}}</ref> Color varies from yellow to white (and firm) depending on the proportion of adipocytic, fibrous and/or myxoid content.<ref name=Mavrogenis2013>{{cite web|url=http://atlasgeneticsoncology.org/Tumors/WellDiffLiposarcomaID5167.html|title=Soft Tissues: Well-differentiated liposarcoma|author=Andreas F Mavrogenis, Panayiotis J Papagelopoulos|date=2013-02-01|website=Atlas of Genetics and Cytogenetics in Oncology and Haematology}}</ref> Areas of fat necrosis are common in larger lesions. Rarely, infiltrative growth is seen.<ref name=Mavrogenis2013/>
-*Submit slices from any suspicious parts, or at least one representative slice from the specimen.
+*'''Submit''' slices from any suspicious parts, or at least one representative slice from the specimen.<ref>{{NU Hospital Group}}</ref> {{Moderate-begin}}A more comprehensive practice is to submit 1 section per centimeter, and 2 sections per cassette.<ref>{{cite web|url=https://voices.uchicago.edu/grosspathology/bone-soft-tissue/lipoma/|title=Lipoma|website=Gross Pathology Manual - By The University of Chicago Department of Pathology|accessdate=2020-08-26}}</ref>{{Moderate-end}}
-<gallery mode=packed>
+<gallery mode=packed heights=200>
 File:Lipoma gross.jpg|thumb|Cross-section of '''lipoma'''. Homogenous texture.
 File:Gross pathology of undifferentiated liposarcoma.jpg|'''Liposarcoma''': Tumor section reveals brownish-yellowish areas, hemorrhagic and calcific zones.
@@ Line 20: / Line 22: @@
 Example:
 {|class="wikitable"
-| Mass weighing 121 grams and measuring 10 x 6,5 x 3,5 cm. Homogenous yellow color. No hemorrhage or necrosis.
+| Mass {{Comprehensive-begin}}weighing 121 grams{{Comprehensive-end}} and measuring 10 x 6,5 x 3,5 cm. {{Comprehensive-begin}}The surgical margin is intact.{{Comprehensive-end}} Cut sections show homogenous yellow color, with no hemorrhage or necrosis. {{Comprehensive-begin}}The specimen is serially sectioned, and representative sections are submitted for microscopic examination in __ cassettes.{{Comprehensive-end}}
 |}
 {{Gross processing}}
@@ Line 26: / Line 28: @@
 ==Microscopic evaluation==
 <gallery mode=packed heights=220>
-File:Histopathology of lipoma.jpg|'''Lipoma''': lobules of mature white adipose tissue divided by delicate and inconspicuous fibrous septa containing thin-walled capillary-sized vessels.
+File:Histopathology of lipoma.jpg|'''Lipoma''': lobules of mature white adipose tissue divided by delicate and inconspicuous fibrous septa containing thin-walled capillary-sized vessels. Still, look close at the fibrous septa:
-File:Histopathology of a fibrolipoma.jpg|'''Fibrolipoma''' is a lipoma with focal areas of large amounts of fibrous tissue.<br>A '''sclerotic lipoma''' is one step further: a predominantly fibrous lesion with focal areas of fat.<ref>{{cite web|url=http://surgpathcriteria.stanford.edu/softfat/lipoma/fibrolipoma.html|title=Lipoma Variant: Fibrolipoma|website=[[Stanford University School of Medicine]]|accessdate=2020-02-10}}</ref><br>If unsure of degree of fibrosis: Simply report as lipoma.
+File:Histopathology of an atypical lipomatous tumor or well-differentiated liposarcoma, lipoma-like subtype.jpg|An '''atypical lipomatous tumor''' (also termed '''well-differentiated liposarcoma'''), lipoma-like subtype. At low magnification, the majority of the tumor essentially has the look of benign mature adipocytes (except for mildly increased variation in lipid droplet sizes), but high magnification of a fibrous band shows spindle cells with enlarged, hyperchromatic nuclei. Another clue for liposarcoma is a higher variability of lipid droplet sizes.
+File:Histopathology of a fibrolipoma.jpg|'''Fibrolipoma''' is a lipoma with focal areas of large amounts of fibrous tissue.<br>A '''sclerotic lipoma''' is one step further: a predominantly fibrous lesion with focal areas of fat.<ref>{{cite web|url=http://surgpathcriteria.stanford.edu/softfat/lipoma/fibrolipoma.html|title=Lipoma Variant: Fibrolipoma|website=Stanford University School of Medicine|accessdate=2020-02-10}}</ref><br>If unsure of degree of fibrosis: Simply report as lipoma.
+File:Histopathology of angiolipoma.jpg|'''Angiolipoma''' is a lipoma with abundant capillaries, with hyaline or fibrin (pictured) thrombi.<ref>{{cite web|url=http://www.pathologyoutlines.com/topic/softtissueadiposeangiolipoma.html|title=Soft tissue - Adipose tissue tumors - Lipoma and variants - Angiolipoma|author=Vijay Shankar|website=Pathology Outlines}} Topic Completed: 1 August 2012. Minor changes: 20 March 2019</ref>
+File:Histopathology of liposarcoma, annotated.jpg|Main features of '''liposarcoma''':<ref name=PathologyOutlines-Liposarcoma>{{cite web|url=https://www.pathologyoutlines.com/topic/softtissuewdliposarcoma.html%7Ctitle=Liposarcoma|author=Michael R. Clay, M.D.|website=PathologyOutlines|title=Liposarcoma}} Topic Completed: 1 November 2017. Minor changes: 11 May 2021</ref><br>- Spindle cells with enlarged, hyperchromatic nuclei.<br>- Apparently univacuolated adipocytes (may look normal).<br>- [[Lipoblast]]s, but is neither necessary nor sufficient for diagnosis.
+File:Lipoblast features, annotated.png|Lipoblast features
 File:Myxoid liposarcoma (16105753363).jpg|'''Myxoid liposarcoma''': Hypercellular solid sheets of cells lying back to back, with round cells or primitive cytomorphology.<ref>{{cite web|url=http://www.pathologyoutlines.com/topic/softtissuemyxoidliposarcoma.html|title=Soft tissue - Adipose tissue - Myxoid liposarcoma|author=Michael R. Clay|website=PathologyOutlines}} Topic Completed: 1 January 2018. Revised: 20 March 2019</ref>
 </gallery>
+A '''pedunculated''' lipomatous skin tumor may be a '''pedunculated lipofibroma''':
+<gallery mode=packed heights=180>
+File:Pedunculated lipofibroma, gross pathology.jpg|Pedunculated lipofibroma, gross pathology
+File:Pedunculated lipofibroma (intermediate magnification).jpg|Histopathology, showing thin rim of epidermis, and dermal lipocytes without capsule.
+</gallery>
+For atypical cases and as a non-subspecialist in soft tissue pathology, generally seek '''expert opinion''', including further workup.
 ===Microscopy/Histopathology report===
-For lipomas: Absence of signs of malignancy.
+For lipomas: {{Moderate-begin}}Absence of signs of malignancy.{{Moderate-end}}
 {|class="wikitable"
-| [[File:Histopathology of lipoma.jpg|190px|left]]
+| [[File:Histopathology of lipoma.jpg|190px|left]] {{Moderate-begin}}Chest wall, left lateral, excision:{{Moderate-end}}
-Tissue composed of univacuolar fat cells and delicate and inconspicuous fibrous septa. No evidence of malignancy.
+*Lipoma.
+*{{Moderate-begin}}Negative for malignancy{{Moderate-end}}
+{{Comprehensive-begin}}Microscopic description: Tissue composed of univacuolar fat cells and delicate and inconspicuous fibrous septa.{{Comprehensive-end}}
 |}
 {{Reporting}}
 {{Bottom}}

Lipomatous tumor: Difference between revisions

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