Adipocytic tumours
Revision as of 19:13, 9 December 2011 by Michael (talk | contribs) (→Hibernoma: +DDx another micro)
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:
DDx:
- Reaction to silicone implant.
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 a characteristic translocation.
- t(12;16)(q13;p11) TLS-CHOP.[21]
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.
- ↑ Knight, JC.; Renwick, PJ.; Dal Cin, P.; Van den Berghe, H.; Fletcher, CD. (Jan 1995). "Translocation t(12;16)(q13;p11) in myxoid liposarcoma and round cell liposarcoma: molecular and cytogenetic analysis.". Cancer Res 55 (1): 24-7. PMID 7805034.