Difference between revisions of "Soft tissue lesions"

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'''Soft tissue lesions''' strike fear in many pathologists as they are uncommon and may be difficult to diagnose.     
'''Soft tissue lesions''' strike fear in many pathologists as they are uncommon and may be difficult to diagnose.     


=Introduction=
==WHO classification of soft tissue lesions/tumours==
==WHO classification of soft tissue lesions/tumours==
===Morphologic grouping<ref name=Ref_WMSP601-3>{{Ref WMSP|601-3}}</ref>===
===Morphologic grouping<ref name=Ref_WMSP601-3>{{Ref WMSP|601-3}}</ref>===
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*Many tumours in soft tissue pathology are diagnosed inconjunction with the finding of [[chromosomal translocations]].
*Many tumours in soft tissue pathology are diagnosed inconjunction with the finding of [[chromosomal translocations]].


==Patterns==
==Histologic patterns==
 
{| class="wikitable sortable" style="margin-left:auto;margin-right:auto"
{| class="wikitable sortable" style="margin-left:auto;margin-right:auto"
! Name
! Name
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|-
|-
| Fasicular
| Fasicular
| description
| the long axis of the (spindle) cells are perpendicular to one another in adjacent bundles of cells
| [[leiomyoma]]
| [[leiomyoma]]
| image ?
| image ?

Revision as of 15:07, 8 April 2011

Soft tissue lesions strike fear in many pathologists as they are uncommon and may be difficult to diagnose.

Introduction

WHO classification of soft tissue lesions/tumours

Morphologic grouping[1]

  1. Adipocytic tumours.
  2. Fibroblastic/myofibroblastic tumours.
  3. "Fibrohistiocytic" tumours.
  4. Smooth muscle tumours.
  5. Skeletal muscle tumours.
  6. Vascular tumours.
  7. Perivascular (pericytic) tumours.
  8. Chondro-osseous tumours.
  9. Tumours of uncertain differentiation.

Biologic potential grouping[2]

  1. Benign.
  2. Intermediate (locally aggressive).
  3. Intermediate (rarely metastasizing).
  4. Malignant.

Prevalence

  • All sarcomas are rare buggers.
    • As the classification has been changing over the past years (with more subtypes being recognized/identified) numbers are variable from study-to-study.
  • Once upon a time almost everything was called malignant fibrous histiocytoma; thus, it is listed as a common entity in some publications.

Most common:[3]

  • Liposarcoma.
  • Leiomyosarcoma.

Molecular testing

Main article: Molecular pathology
  • Molecular testing plays an important role in soft tissue pathology.
  • It is generally seen as an adjunct test that:[4]
    • Often is used to confirm the histomorphologic impression/quality control.
    • Frequently has some prognostic significance.
    • May directly affect treatment.

Translocations

Main article: Chromosomal translocations

Histologic patterns

Name Description DDx Image Other
Storiform, AKA patternless pattern[5] whorled, cartwheel-like arrangement Undifferentiated pleomorphic sarcoma image ? other ?
Herring bone like herring bone (technique) for climbing a hill in cross country skiing; books on a shelf, where they have partially fallen over -- on the one shelf to the left and the one below to the right fibrosarcoma, synovial sarcoma, MPNST image ? other ?
Fasicular the long axis of the (spindle) cells are perpendicular to one another in adjacent bundles of cells leiomyoma image ? other ?
Biphasic nests of cells and stroma synovial sarcoma, DSRCT, alveolar RMS image ? other ?

Adipocytic tumours

Main article: Adipocytic tumours

This category includes:

  • Lipoma.
  • Liposarcoma.
  • Hibernoma.

Smooth muscle tumours

Leiomyosarcoma

See gyne notes.

Microscopy

Features:

Fibrohistiocytic tumours

Undifferentiated pleomorphic sarcoma

  • Abbreviated UPS.
  • Previously known as malignant fibrous histiocytoma.[6]

General

  • Common sarcoma.
  • Usu. deep tissue of the trunk and extremities.

Microscopic

Features:[7]

  • Storiform pattern (AKA patternless pattern - key feature.
  • Marked nuclear pleomorphism key feature.
    • Variation is nuclear size, nuclear shape and nuclear staining (esp. hyperchromasia).
  • Mitoses - abundant; atypical mitoses common.
  • Necrosis (common).
  • Mix of spindle cells and epithelioid cells.

Other findings:

  • +/-Giant cells (see subclassification).
  • +/-Inflammation (see subclassification).
    • Neutrophils.
    • Eosinophils.

Subclassification

UPS is subclassified the following way:[8]

  • UPS with giant cells.
  • UPS with inflammation.
  • UPS not otherwise specified (NOS) - wastebasket diagnosis; if neither of the above two apply.

Fibroblastic/myofibroblastic tumours

Proliferative fasciitis

  • Need to write something here.

Solitary fibrous tumour

General

  • Grouped with hemangiopericytoma in the WHO classification; possibly the same tumour (?).[9]
  • May be benign or malignant; more commonly benign.[10][11]

Microscopic

Features:

  • Well-circumscribed.
  • Fibroblast-like cells (spindle cells).
  • Hemangiopericytoma-like area (staghorn vessels) - not seen on image.
  • Keloid-like collagen bundles.

Images:

Hemangiopericytoma

General

  • Grouped with solitary fibrous tumour in the WHO classification; possibly the same tumour (?).[9]
  • Arises from the pericyte, a connective tissue cell of small vessels that is thought to be involved in flow regulation.
  • Hematologic spread most common - to lungs.[12]
  • Oncogenic osteomalacia - assoc. with hemangiopericytoma.[13]

Presentation

  • Usually painless mass, slow enlargement.

Radiology

  • Intramedullary lytic mass.
  • May be well-circumscribed.
  • +/-Periosteal reaction.
  • +/-Sclerotic border.

May be worked-up with angiography to distinguish from a vascular malformation.[14]

Location

  • Usually extremities - femur or prox. tibial.[15]

Histology

Features:[16]

  • Hypervascular lesion - key diagnostic feature.[17]
    • Abundant thin-walled branching small vessels of variable size.
      • May be described as "staghorn vessels" or "antler-like" vasculature.
      • Cells may "onion-skin" around thin blood vessels.
  • Spindle or ovoid shaped cells in nests or sheets.

IHC

Features:[9][17]

  • Vimentin +ve (usually).
  • Desmin -ve (typical).
  • Factor VIII -ve (marks endothelium).
  • CD34 +ve.
    • CD34 usu. -ve in synovial sarcoma.
  • CD31 -ve (marks benign endothelium).
  • vWF (von Willebrand factor) -ve.

May be in the DDx for meningioma:[18]

  • EMA -ve.
  • S100 -ve.

DDx

  • Other vascular tumours.
  • Vascular malformations.
  • Synovial sarcoma.

Desmoplastic fibroblastoma

  • AKA collagenous fibroma.[19]
  • Benign lesion.
  • Classically found in shoulder region.

IHC

  • Beta-catenin -ve.[20]
    • Significance ???

Low-grade fibromyxoid sarcoma

  • AKA hyalinizing spindle cell tumour.

General

  • Deep soft tissue.

Microscopic

Features:[21]

  • Myoid stroma - key feature.
  • Low cellularity.
  • Spindle cells.

Notes:

  • Few/absent mitoses.

Molecular pathology

t(7;16)(q33;p11)[22]

Vascular lesions

Vascular lesions are "too red"; they have too many RBCs.

Hemangioma

General

Comes is various flavours:[23]

  • Tufted.
    • Small clusters of blood vessels.
  • Microvenular hemangioma.
  • Glomeruloid hemangioma.
  • Epithelioid hemangioma.
  • Targetoid hemosideric hemangioma.

Microscopic

Features:

  • Abundance of benign small blood vessels. (???)

Kaposi sarcoma

General

  • Not really a sarcoma.
  • Caused by HHV-8.
  • Associated with immunodeficiency, e.g. HIV/AIDS.

Stages

It is seen in different stages:[24]

  1. Patch stage.
  2. Plaque stage.
  3. Nodular stage.
  4. Lymphangioma-like. (???)

Microscopic

Features:[25]- key feature.

  • +/-Nuclear atypia.
  • Hyaline globules (intracytoplasmic)[26] - pale pink globs (that are paler than RBCs) - important feature.
  • +/-Hemosiderin deposits.

DDx:

  • Angiosarcoma (have many mitoses, nuclear atypia).
  • Masson's hemangioma (Intravascular papillary endothelial hyperplasia).

Notes:

Images:

IHC

  • CD31 +ve.
  • CD34 +ve.
  • HHV-8 +ve.

Masson hemangioma

General

  • Benign non-neoplastic lesion - a vessel that has thrombosed and recanalized.
  • AKA intravascular papillary endothelial hyperplasia.[29]
  • Histomorphologically may be confused with low-grade angiosarcoma or other soft tissue sarcomas.[29]

Microscopic

Features:

  • Well-circumscribed - key (low power) feature.
  • Abundant small vascular channels with benign endothelium.

Notes:

  • Looks like Kaposi sarcoma at high power.

Angiosarcoma

General

  • Malignant tumour - with a horrible prognosis.[30]
  • Classically on the scalp or head & neck.
  • May arise secondary to therapeutic radiation or chronic lymphoedema related to breast carcinoma.

Microscopic

Features:

  • Very many small capillaries of irregular shape lined with:
    • Pleomorphic nuclei.
      • May have hobnail morphology.
  • Mitoses.
  • Cytoplasmic vacuoles.
    • Cells trying to form lumina - embryologic.

Notes:

IHC

  • CD34 +ve.
  • D2-40 +ve. (???)
  • CD31 +ve.

Hemangioendothelioma

General

  • Usually benign.

Microscopic

Features:[25]

  • Well-formed thin vascular channels on a fibrous stroma - key feature.
  • +/-Thrombosis.
  • +/-Calcification.
  • +/-Fibrosis.
  • +/-Myxoid change.

IHC

  • Factor VIII +ve.

Skeletal muscle tumours

Rhabdomyoma

Main article: Rhabdomyoma

Rhabdomyosarcoma

  • Abbreviated RMS.
Main article: Rhabdomyosarcoma

Comes it two main flavours:

  • Alveolar rhabdomyosarcoma.
  • Embryonal rhabdomyosarcoma.

The histology may be that of a small round cell tumour.

Chondro-osseous tumours

Main article: Chondro-osseous tumours

This grouping includes tumours derived from cartilage and bone.

Tumours of uncertain differentiation

Desmoplastic small round cell tumour

  • Abbreviated DSRCT.

General

  • Males > females.
  • Usu. affects young adults.
  • Typically retroperitoneal.
  • Poor prognosis.

Microscopic

Features:[31]

  1. Broad bands of paucicellular fibrous stroma with:
  2. Small round cells in nests with an undulating sharp border.

Notes:

  • Usu. abundant mitoses.
  • +/-Necrosis.

Images:

DDx:

IHC

Features:

  • AE1/AE3 +ve.
  • Desmin +ve.
  • EMA +ve.

Molecular

Clear cell sarcoma

  • Known among pathologists as "soft-tissue melanoma" and "melanoma of the soft parts", as it has a strong morphological resemblance.[34]
    • Molecular changes and origin distinct from melanoma.
  • Incidence: rare soft tissue tumour.

Clinical

  • Usually - deep soft tissue or extremities.
  • Guarded prognosis.
  • First described in 1965.[35]

Microscopy

Features:[34]

  • Architecture: sheets or fascicular (bundles) arrangement.
  • Cells: Spindle cells or epithelioid cells.
  • Prominent nucleoli - basophilic.
  • Fibrous septae.
  • Uniform

Image:

IHC

Features:[34]

  • S100 +ve.
  • HMB-45 +ve.
  • Melan A (MART-1) +ve; sometimes -ve.
  • BCL2 +ve.
  • CD57 +ve (usually).

Keratins:

  • EMA may be +ve.
  • CAM5.2 -ve.
  • AE1/AE3 -ve.

Molecular studies

  • Chromosomal translocation t(12;22)(q13;q12).[34]
    • Fusion transcripts:
      • EWSR1-ATF1.
      • EWSR1-CREB1 (GI tract associated).

Synovial sarcoma

General

  • Does not arise from cartilage.[36]
  • Young adults or adolescents.

Microscopic

Comes in three flavours:[36][37]

  1. Spindle cell sarcoma with features of hemangiopericytoma, i.e. staghorn vessels.
  2. Biphasic synovial sarcoma:
    1. Spindle cells with features of hemangiopericytoma.
    2. Epitheliod glands or nests.
  3. Primative round cell type.

Images:

IHC

Features:[36]

  • Vimentin +ve + cytokeratin and/or EMA +ve.
  • CD99 +ve.

Others:

Molecular pathology

Unique translocation:

  • t(X;18)(p11.2;q11.2).[40]

See also

References

  1. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 601-3. ISBN 978-0781765275.
  2. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 598-604. ISBN 978-0781765275.
  3. ↑ Skubitz KM, D'Adamo DR (November 2007). "Sarcoma". Mayo Clin. Proc. 82 (11): 1409–32. PMID 17976362. http://www.mayoclinicproceedings.com/content/82/11/1409.long.
  4. ↑ Fletcher CD, Fletcher JA, Dal Cin P, Ladanyi M, Woodruff JM (July 2001). "Diagnostic gold standard for soft tissue tumours: morphology or molecular genetics?". Histopathology 39 (1): 100–3. PMID 11454050.
  5. ↑ Mangano WE, Cagle PT, Churg A, Vollmer RT, Roggli VL (August 1998). "The diagnosis of desmoplastic malignant mesothelioma and its distinction from fibrous pleurisy: a histologic and immunohistochemical analysis of 31 cases including p53 immunostaining". Am. J. Clin. Pathol. 110 (2): 191–9. PMID 9704618.
  6. ↑ URL: http://sarcomahelp.org/learning_center/mfh.html. Accessed on: 8 April 2011.
  7. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 613. ISBN 978-0781765275.
  8. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 613-4. ISBN 978-0781765275.
  9. ↑ 9.0 9.1 9.2 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 609. ISBN 978-0781765275.
  10. ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970528-9. Accessed on: 25 June 2010.
  11. ↑ URL: http://wjso.com/content/6/1/86. Accessed on: 25 June 2010.
  12. ↑ URL: http://emedicine.medscape.com/article/1255879-overview. Accessed on: 2 May 2010.
  13. ↑ URL: http://emedicine.medscape.com/article/1255879-overview. Accessed on: 2 May 2010.
  14. ↑ URL: http://emedicine.medscape.com/article/1255879-diagnosis. Accessed on: 2 May 2010.
  15. ↑ URL: http://emedicine.medscape.com/article/1255879-overview. Accessed on: 2 May 2010.
  16. ↑ URL: http://emedicine.medscape.com/article/1255879-diagnosis. Accessed on: 2 May 2010.
  17. ↑ 17.0 17.1 Enzinger & Weiss's Soft Tissue Tumors. 4th Ed. PP.1007-13. ISBN 0-323-01200-0.
  18. ↑ Croul, SE. 8 November 2010.
  19. ↑ Watanabe, H.; Ishida, Y.; Nagashima, K.; Makino, T.; Norisugi, O.; Shimizu, T. (Feb 2008). "Desmoplastic fibroblastoma (collagenous fibroma).". J Dermatol 35 (2): 93-7. doi:10.1111/j.1346-8138.2008.00421.x. PMID 18271804.
  20. ↑ Takahara, M.; Ichikawa, R.; Oda, Y.; Uchi, H.; Takeuchi, S.; Moroi, Y.; Kiryu, H.; Furue, M. (Oct 2008). "Desmoplastic fibroblastoma: a case presenting as a protruding nodule in the dermis.". J Cutan Pathol 35 Suppl 1: 70-3. doi:10.1111/j.1600-0560.2007.00964.x. PMID 18544056.
  21. ↑ Vernon SE, Bejarano PA (September 2006). "Low-grade fibromyxoid sarcoma: a brief review". Arch. Pathol. Lab. Med. 130 (9): 1358–60. PMID 16948525.
  22. ↑ Panagopoulos I, Storlazzi CT, Fletcher CD, et al. (July 2004). "The chimeric FUS/CREB3l2 gene is specific for low-grade fibromyxoid sarcoma". Genes Chromosomes Cancer 40 (3): 218–28. doi:10.1002/gcc.20037. PMID 15139001.
  23. ↑ Prieto VG, Shea CR (July 1999). "Selected cutaneous vascular neoplasms. A review". Dermatol Clin 17 (3): 507–20, viii. PMID 10410855.
  24. ↑ URL: http://www.histopathology-india.net/KS.htm. Accessed on: 31 January 2010.
  25. ↑ 25.0 25.1 Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 23. ISBN 978-1416002741.
  26. ↑ 26.0 26.1 del Rosario AD, Bui HX, Singh J, Ginsburg R, Ross JS (December 1994). "Intracytoplasmic eosinophilic hyaline globules in cartilaginous neoplasms: a surgical, pathological, ultrastructural, and electron probe x-ray microanalytic study". Hum. Pathol. 25 (12): 1283–9. PMID 7528163.
  27. ↑ Lazova R, McNiff JM, Glusac EJ, Godic A (April 2009). "Promontory sign--present in patch and plaque stage of angiosarcoma!". Am J Dermatopathol 31 (2): 132–6. doi:10.1097/DAD.0b013e3181951045. PMID 19318797.
  28. ↑ Fernandez-Flores A, Rodriguez R (June 2010). "Promontory Sign in a Reactive Benign Vascular Proliferation". Am J Dermatopathol. doi:10.1097/DAD.0b013e3181cf0ae5. PMID 20577080.
  29. ↑ 29.0 29.1 Korkolis DP, Papaevangelou M, Koulaxouzidis G, Zirganos N, Psichogiou H, Vassilopoulos PP (2005). "Intravascular papillary endothelial hyperplasia (Masson's hemangioma) presenting as a soft-tissue sarcoma". Anticancer Res. 25 (2B): 1409–12. PMID 15865098.
  30. ↑ Young RJ, Brown NJ, Reed MW, Hughes D, Woll PJ (May 2010). "Angiosarcoma". Lancet Oncol. doi:10.1016/S1470-2045(10)70023-1. PMID 20537949.
  31. ↑ Pickhardt PJ, Fisher AJ, Balfe DM, Dehner LP, Huettner PC (March 1999). "Desmoplastic small round cell tumor of the abdomen: radiologic-histopathologic correlation". Radiology 210 (3): 633–8. PMID 10207460. http://radiology.rsna.org/content/210/3/633.full.
  32. ↑ Lee YS, Hsiao CH (October 2007). "Desmoplastic small round cell tumor: a clinicopathologic, immunohistochemical and molecular study of four patients". J. Formos. Med. Assoc. 106 (10): 854–60. doi:10.1016/S0929-6646(08)60051-0. PMID 17964965.
  33. ↑ Lal DR, Su WT, Wolden SL, Loh KC, Modak S, La Quaglia MP (January 2005). "Results of multimodal treatment for desmoplastic small round cell tumors". J. Pediatr. Surg. 40 (1): 251–5. doi:10.1016/j.jpedsurg.2004.09.046. PMID 15868593. http://www.dsrct.com/JPS%20Article.pdf.
  34. ↑ 34.0 34.1 34.2 34.3 Hisaoka M, Ishida T, Kuo TT, et al. (March 2008). "Clear cell sarcoma of soft tissue: a clinicopathologic, immunohistochemical, and molecular analysis of 33 cases". Am. J. Surg. Pathol. 32 (3): 452–60. doi:10.1097/PAS.0b013e31814b18fb. PMID 18300804.
  35. ↑ URL: http://www.informaworld.com/smpp/723576818-750600/ftinterface~db=all~content=a789166263~fulltext=713240928. Accessed on: 5 May 2010.
  36. ↑ 36.0 36.1 36.2 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 627. ISBN 978-0781765275.
  37. ↑ Schaal CH, Navarro FC, Moraes Neto FA (2004). "Primary renal sarcoma with morphologic and immunohistochemical aspects compatible with synovial sarcoma". Int Braz J Urol 30 (3): 210–3. PMID 15689250. http://www.brazjurol.com.br/may_june_2004/Schaal_ing_210_213.htm.
  38. ↑ 38.0 38.1 Horvai AE, Kramer MJ, O'Donnell R (June 2006). "Beta-catenin nuclear expression correlates with cyclin D1 expression in primary and metastatic synovial sarcoma: a tissue microarray study". Arch. Pathol. Lab. Med. 130 (6): 792–8. PMID 16740029.
  39. ↑ Ng TL, Gown AM, Barry TS, et al. (January 2005). "Nuclear beta-catenin in mesenchymal tumors". Mod. Pathol. 18 (1): 68–74. doi:10.1038/modpathol.3800272. PMID 15375433.
  40. ↑ URL: http://www.ncbi.nlm.nih.gov/omim/300813. Accessed on: 30 May 2010.
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