Difference between revisions of "Adipocytic tumours"
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*Microscopically ''not'' definitely distinguishable from mature clump of fat. | *Microscopically ''not'' definitely distinguishable from mature clump of fat. | ||
**The lesion must be labeled ''lipoma'' to be signed-out as such. | **The lesion must be labeled ''lipoma'' (by the clinican) to be signed-out as such. | ||
Images: | Images: | ||
Revision as of 16:38, 26 November 2011
Adipocytic tumours fall into the grouping soft tissue lesions and includes things that are very common (e.g. lipoma) and everything from benign to malignant.
Overview
This grouping includes a number of tumours, which can be divided based on their behaviour into benign, intermediate and malignant.
Benign
Benign adipocytic tumours:[1]
- Lipoma.
- Angiolipoma.
- Myolipoma.
- Pleomorphic lipoma/spindle cell lipoma.
- Lipomatosis.
- Lipomatosis of nerve.
- Lipoblastoma.
- Extrarenal angiomyolipoma.
- Extra-adrenal myelolipoma.
- Hibernoma.
Intermediate
Intermediate adipocytic tumours:[1]
- Atypical lipomatous tumour.
Malignant
Malignant adipocytic tumours:[1]
- Dedifferentiated liposarcoma.
- Myxoid liposarcoma.
- Pleomorphic liposarcoma.
- Mixed-type liposarcoma.
- Liposarcoma NOS.
Detail section
Normal mature fat
Microscopic
Features:
- Adipocytes of approximately equal size.
- Not vascular.
- No nuclear hyperchromasia.
Notes:
- May have nuclear pseudoinclusions (Lockhern cell).[2]
- There is some suggestion this is not benign.[3]
IHC
- S100 +ve.
Lipoma
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.[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.
Images:
Variants
Angiolipoma
Microscopic:
- Numerous blood vessels present.
Myolipoma
Microscopic:
- Muscle present.
Pleomorphic lipoma
General
- Rare.
- May mimic a malignancy.[6]
- Classically shoulder and neck region in adults.[7]
- Male > female.[8]
Microscopic
Features:
- Multinucleated cells - "floret cells" - key feature.
- Solid eosinophilic cytoplasm.
- Peripheral nuclei - impart a knobby border to the cells.
- Fibrous septa.
Notes:
- May overlap with spindle cell lipoma.[9]
- Floret cell - may look similar to Touton giant cells.
Images:
- Pleomorphic lipoma - low mag. (webpathology.com).
- Pleomorphic lipoma - high mag. (webpathology.com).
DDx:
- Liposarcoma.
- Ancient neurofibroma.
- Ancient schwannoma.
IHC
- AR +ve - ~95% in men, ~85% in women.[8]
Spindle cell lipoma
General
- Rare.
- Predominantly men.[10]
Note:
- Spindle cell lipoma may immunohistochemically and histomorphologically overlap with mammary-type myofibroblastoma[11] - see: mammary myofibroblastoma.
Microscopic
Features:[10]
- Aligned bland spindled cells adjacent to fat.
- Rope-like collagen bundles - key feature.
- May be described as "shreaded wheat".
- +/-Myxoid component.
- +/-Staghorn-like vessels.
Notes:
- May overlap with pleomorphic lipoma.[9]
DDx:
Image:
IHC
- CD34 +ve.[12]
- Desmin +ve.
Hibernoma
General
- Consists of brown fat (present in the infants to generate heat).[13]
- Benign.
- Usually asymptomatic.[14]
Epidemiology
- Young adults.
Gross
- Well-circumscribed.
- Lobulated and light-brown on sectioning.
Microscopic
Features:[15]
- Large polygonal/oval cells:
Image:
Atypical lipomatous tumour
- AKA well-differentiated liposarcoma, abbreviated WDLPS.
- Abbreviated ALT/WDLPS.
General
- Atypical lipomatous tumour is a term used to save people with a (curable) peripheral liposarcoma from getting denied life insurance.
Microscopic
Features:[18]
- Large adipocytes.
- Atypical lipoblasts - focal, scattered:
- Nuclear hyperchromasia.
- +/-Multinucleated.
Liposarcoma
General
- Most common malignant sarcoma in the retroperitoneum.
- Not all (large) retroperitoneal adipocytic tumours are liposarcomas.
Notes:
- Retroperitoneal sarcomas: #1: liposarcoma, #2: pleomorphic undifferentiated sarcoma, #3: leiomyosarcoma, #4: MPNST.
- Extremely rare in retroperitoneum: synovial sarcoma.
Microscopic
Features:
- Lipoblasts - key feature.
- Large sharply demarcated vacuole.
- Nucleus:
- Hyperchromatic (dark staining) nucleus.
- Eccentric location.
- Nuclear indentation.
- Chicken wire-like vascular.
- +/-Myxoid background.
- Cell size variation.
Images:
- Myxoid liposarcoma (WC).
- Myxoid liposarcoma (WC).
- Lipoblasts (john-libbey-eurotext.fr).
- Dediff. liposarcoma - lipoblasts - very high mag. (WC).
- Dediff. liposarcoma - shows dediff. component - intermed. mag. (WC).
Subtypes
There are several subtypes:[1]
- Dedifferentiated liposarcoma.
- Myxoid liposarcoma.
- Mixed-type liposarcoma.
- Pleomorphic liposarcoma.
- Liposarcoma not otherwise specified (NOS).
Myxoid liposarcoma
- Has characteristic translocations.
Features:
- Chickenwire-type blood vessels.
Dedifferentiated liposarcoma
- Has an undifferentiated component that, if seen alone, would be diagnosed as pleomorphic undifferentiated sarcoma.
- The diagnosis depends on the presence of the differentiated component of the tumour, i.e. the presence of lipoblasts.
IHC
- IHC is of limited value.
- S-100 +ve ~1/3 of the time.
- Reticulin ???.
See also
References
- ↑ 1.0 1.1 1.2 1.3 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 601. ISBN 978-0781765275.
- ↑ URL: http://journals.lww.com/amjdermatopathology/Citation/2004/12000/Original_Observation_to_Rediscovery__Nuclear.9.aspx. Accessed on: 18 April 2011.
- ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970574-5. Accessed on: 18 April 2011.
- ↑ Mentzel, T.; Fletcher, CD. (1995). "Lipomatous tumours of soft tissues: an update.". Virchows Arch 427 (4): 353-63. PMID 8548119.
- ↑ 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.
- ↑ Persichetti, P.; Di Lella, F.; Marangi, GF.; Cagli, B.; Simone, P.; Tenna, S.; Rabitri, C.; Cassandro, R. et al. "Pleomorphic lipoma: a definite histopathological entity.". Anticancer Res 24 (5B): 3157-9. PMID 15510605.
- ↑ URL: http://www.webpathology.com/image.asp?n=2&Case=435. Accessed on: 3 October 2011.
- ↑ 8.0 8.1 Syed, S.; Martin, AM.; Haupt, H.; Podolski, V.; Brooks, JJ. (Jan 2008). "Frequent detection of androgen receptors in spindle cell lipomas: an explanation for this lesion's male predominance?". Arch Pathol Lab Med 132 (1): 81-3. doi:10.1043/1543-2165(2008)132[81:FDOARI]2.0.CO;2. PMID 18181679.
- ↑ 9.0 9.1 URL: http://surgpathcriteria.stanford.edu/softfat/spindle_cell_lipoma/. Accessed on: 4 December 2010.
- ↑ 10.0 10.1 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.
- ↑ McMenamin, ME.; Fletcher, CD. (Aug 2001). "Mammary-type myofibroblastoma of soft tissue: a tumor closely related to spindle cell lipoma.". Am J Surg Pathol 25 (8): 1022-9. PMID 11474286.
- ↑ Wood, L.; Fountaine, TJ.; Rosamilia, L.; Helm, KF.; Clarke, LE. (Dec 2010). "Cutaneous CD34+ spindle cell neoplasms: Histopathologic features distinguish spindle cell lipoma, solitary fibrous tumor, and dermatofibrosarcoma protuberans.". Am J Dermatopathol 32 (8): 764-8. doi:10.1097/DAD.0b013e3181d0c587. PMID 20559119.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 605. ISBN 978-0781765275.
- ↑ Ahmed SA, Schuller I (December 2008). "Pediatric hibernoma: a case review". J. Pediatr. Hematol. Oncol. 30 (12): 900–1. doi:10.1097/MPH.0b013e318184e6dd. PMID 19131775.
- ↑ Chen DY, Wang CM, Chan HL (March 1998). "Hibernoma. Case report and literature review". Dermatol Surg 24 (3): 393–5. PMID 9537018.
- ↑ http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675(06)70271-6
- ↑ http://surgpathcriteria.stanford.edu/softfat/hibernoma/
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 605. ISBN 978-0781765275.
- ↑ Smith, TA.; Easley, KA.; Goldblum, JR. (Feb 1996). "Myxoid/round cell liposarcoma of the extremities. A clinicopathologic study of 29 cases with particular attention to extent of round cell liposarcoma.". Am J Surg Pathol 20 (2): 171-80. PMID 8554106.
- ↑ Conyers, R.; Young, S.; Thomas, DM. (2011). "Liposarcoma: molecular genetics and therapeutics.". Sarcoma 2011: 483154. doi:10.1155/2011/483154. PMID 21253554.