Adipocytic tumours

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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]

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

Lipoblastoma

General

  • Rare paediatric tumour.[4]

Usual presentation:[4]

  • Painless neck mass.

Microscopic

Features:

  • Nests of cells in the dermis with abundant pale cytoplasm - vaguely resemble adipocytes.
    • Smaller than mature adipocytes.

DDx:

Images:

Lipoma

Pleomorphic lipoma

General

  • Rare.
  • May mimic a malignancy.[6]
  • Male > female.[7]

Gross

  • Classically shoulder and neck region in adults.[8]

DDx - shoulder lesions:

Microscopic

Features:

  • Multinucleated cells - "floret cells" - key feature.
    • Solid eosinophilic cytoplasm.
    • Peripheral nuclei - impart a knobby border to the cells.
  • Fibrous septa.

Notes:

Images:

DDx:

IHC

  • AR +ve - ~95% in men, ~85% in women.[7]
  • CD34 +ve (26 +ve of 26 cases[11]).
  • Desmin -ve (0 +ve of 20 cases[11]).
  • ER -ve/+ve (5 +ve of 21 cases[11]).

Spindle cell lipoma

General

  • Rare.
  • Predominantly men.[12]

Note:

  • Spindle cell lipoma may immunohistochemically and histomorphologically overlap with mammary-type myofibroblastoma[13] - see: mammary myofibroblastoma.

Microscopic

Features:[12]

  • 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:

DDx:

Image

www:

IHC

  • CD34 +ve.[15]
  • Desmin +ve.
  • S100 -ve. (???)

Lipoma versus liposarcoma:

Molecular

  • Retinoblastoma (Rb) deletions.[17]
  • CDK4 no amplication (FISH).[17]

Hibernoma

Atypical lipomatous tumour

  • AKA well-differentiated liposarcoma, abbreviated WDLPS.[17]
  • 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

See also

References

  1. 1.0 1.1 1.2 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.
  2. URL: http://journals.lww.com/amjdermatopathology/Citation/2004/12000/Original_Observation_to_Rediscovery__Nuclear.9.aspx. Accessed on: 18 April 2011.
  3. URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970574-5. Accessed on: 18 April 2011.
  4. 4.0 4.1 Pham, NS.; Poirier, B.; Fuller, SC.; Dublin, AB.; Tollefson, TT. (Jul 2010). "Pediatric lipoblastoma in the head and neck: a systematic review of 48 reported cases.". Int J Pediatr Otorhinolaryngol 74 (7): 723-8. doi:10.1016/j.ijporl.2010.04.010. PMID 20472310.
  5. Nagano, A.; Ohno, T.; Nishimoto, Y.; Hirose, Y.; Miyake, S.; Shimizu, K. (2011). "Lipoblastoma mimicking myxoid liposarcoma: a clinical report and literature review.". Tohoku J Exp Med 223 (1): 75-8. PMID 21212605.
  6. 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.
  7. 7.0 7.1 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.
  8. URL: http://www.webpathology.com/image.asp?n=2&Case=435. Accessed on: 3 October 2011.
  9. 9.0 9.1 URL: http://surgpathcriteria.stanford.edu/softfat/spindle_cell_lipoma/. Accessed on: 4 December 2010.
  10. Azzopardi, JG.; Iocco, J.; Salm, R. (Jul 1983). "Pleomorphic lipoma: a tumour simulating liposarcoma.". Histopathology 7 (4): 511-23. PMID 6884998.
  11. 11.0 11.1 11.2 Cheah, A.; Billings, S.; Goldblum, J.; Hornick, J.; Uddin, N.; Rubin, B. (Feb 2015). "Spindle cell/pleomorphic lipomas of the face: an under-recognized diagnosis.". Histopathology 66 (3): 430-7. doi:10.1111/his.12548. PMID 25219904.
  12. 12.0 12.1 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.
  13. 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.
  14. Dei Tos, AP.; Mentzel, T.; Newman, PL.; Fletcher, CD. (Sep 1994). "Spindle cell liposarcoma, a hitherto unrecognized variant of liposarcoma. Analysis of six cases.". Am J Surg Pathol 18 (9): 913-21. PMID 8067512.
  15. 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.
  16. Alshenawy, H. (Jun 2013). "Can HMGI-C be used as an aid with MDM2 and CDK4 to differentiate liposarcoma subtypes from their mimics?". J Cancer Res Clin Oncol 139 (6): 1073-81. doi:10.1007/s00432-013-1420-6. PMID 23529275.
  17. 17.0 17.1 17.2 17.3 Creytens, D.; van Gorp, J.; Savola, S.; Ferdinande, L.; Mentzel, T.; Libbrecht, L. (Jul 2014). "Atypical spindle cell lipoma: a clinicopathologic, immunohistochemical, and molecular study emphasizing its relationship to classical spindle cell lipoma.". Virchows Arch 465 (1): 97-108. doi:10.1007/s00428-014-1568-8. PMID 24659226.
  18. 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.