Difference between revisions of "Soft tissue lesions"

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=Skeletal muscle tumours=
=Skeletal muscle tumours=
==Rhabdomyoma==
{{Main|Rhabdomyoma}}
==Rhabdomyosarcoma==
==Rhabdomyosarcoma==
*Often abbreviated ''RMS''.
*Abbreviated ''RMS''.
===General===
*Most common paediatric sarcoma.
*~6% of all childhood cancer.
 
Histological subdivision:
#Alveolar rhabdomyosarcoma.
#*Usually young adults/adolescents.
#*Early mets common.
#Embryonal rhabdomyosarcoma.
#*Usual <10 years old.
#*Typically locally invasive.
 
Molecular and histologic subdivision:
#Translocation-positive alveolar RMS.
#Translocation-negative alveolar RMS.
#Embryonal RMS.
 
Notes:
*Translocation-negative alveolar RMS shares characteristics with ''embryonal RMS''.
 
===Microscopy===
Alveolar rhabdomyosarcoma:
*Alveolus-like pattern:
**Fibrous septae lined by tumour cells.
***Space between fibrous sepate may be filled with tumour: ''solid variant of alveolar rhabdomyosarcoma''.
*Eccentric nucleus (???).
*Cytoplasm - dense pink staining on H&E (if well differentiated).
*Usu. nuclear pleomorphism +++.
*Mitoses common.
 
===Molecular diagnostics===
====Alveolar rhabdomyosarcoma====
Common translocations (~80%):
*t(1,13).
**PAX7/FKHR fusion gene.
*t(2,13).<ref>URL: [http://www.ncbi.nlm.nih.gov/omim/606597 http://www.ncbi.nlm.nih.gov/omim/606597]. Accessed on: 18 August 2010.</ref>
**PAX3/FKHR fusion gene.


Several uncommon translocations exist.
{{Main|Rhabdomyosarcoma}}
Comes it two main flavours:
*Alveolar rhabdomyosarcoma.
*Embryonal rhabdomyosarcoma.


===IHC===
The histology may be that of a [[small round cell tumour]].
*Desmin (best marker).
*Actin.


=Chondro-osseous tumours=
=Chondro-osseous tumours=

Revision as of 20:03, 7 March 2011

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

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

  • 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.

Adipocytic tumours

Main article: Adipocytic tumours

This category includes:

  • Lipoma.
  • Liposarcoma.
  • Hibernoma.

Smooth muscle tumours

Leiomyosarcoma

See gyne notes.

Microscopy

Features:

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 (?).[5]
  • May be benign or malignant; more commonly benign.[6][7]

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 (?).[5]
  • 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.[8]
  • Oncogenic osteomalacia - assoc. with hemangiopericytoma.[9]

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.[10]

Location

  • Usually extremities - femur or prox. tibial.[11]

Histology

Features:[12]

  • Hypervascular lesion - key diagnostic feature.[13]
    • 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:[5][13]

  • 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:[14]

  • EMA -ve.
  • S100 -ve.

DDx

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

Desmoplastic fibroblastoma

  • AKA collagenous fibroma.[15]
  • Benign lesion.
  • Classically found in shoulder region.

IHC

  • Beta-catenin -ve.[16]
    • Significance ???

Vascular lesions

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

Hemangioma

General

Comes is various flavours:[17]

  • 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:[18]

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

Microscopic

Features:[19]- key feature.

  • +/-Nuclear atypia.
  • Hyaline globules (intracytoplasmic)[20] - 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.[23]
  • Histomorphologically may be confused with low-grade angiosarcoma or other soft tissue sarcomas.[23]

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.[24]
  • 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:[19]

  • 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

Clear cell sarcoma

  • Known among pathologists as "soft-tissue melanoma" and "melanoma of the soft parts", as it has a strong morphological resemblance.[25]
    • 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.[26]

Microscopy

Features:[25]

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

Image:

IHC

Features:[25]

  • 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).[25]
    • Fusion transcripts:
      • EWSR1-ATF1.
      • EWSR1-CREB1 (GI tract associated).

Chondrosarcoma

General

  • May arise from an enchondroma.
  • Usually a good prognosis.

Microscopic

Features:

  • Resembles cartilage at low power.[27]
  • More cellular than cartilage... but relatively paucicellular compared to other sarcomas.

Images:

DDx:

Grading

Features:[28]

  • Grade I: moderate cellularity +/- binucleated cells.
  • Grade III: nuclear pleomorphism, mitoses common.
  • Grade II: between Grade I and Grade III.

IHC

  • S-100 -ve. (???)

Mesenchymal chondrosarcoma

Microscopic

Features:

  • "White clouds in a blue sky".

Image:

Synovial sarcoma

General

  • Does not arise from cartilage.[29]
  • Young adults or adolescents.

Microscopic

Comes in three flavours:[29][30]

  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:[29]

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

Others:

Molecular pathology

Unique translocation:

  • t(X;18)(p11.2;q11.2).[33]

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. ↑ 5.0 5.1 5.2 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.
  6. ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970528-9. Accessed on: 25 June 2010.
  7. ↑ URL: http://wjso.com/content/6/1/86. Accessed on: 25 June 2010.
  8. ↑ URL: http://emedicine.medscape.com/article/1255879-overview. Accessed on: 2 May 2010.
  9. ↑ URL: http://emedicine.medscape.com/article/1255879-overview. Accessed on: 2 May 2010.
  10. ↑ URL: http://emedicine.medscape.com/article/1255879-diagnosis. Accessed on: 2 May 2010.
  11. ↑ URL: http://emedicine.medscape.com/article/1255879-overview. Accessed on: 2 May 2010.
  12. ↑ URL: http://emedicine.medscape.com/article/1255879-diagnosis. Accessed on: 2 May 2010.
  13. ↑ 13.0 13.1 Enzinger & Weiss's Soft Tissue Tumors. 4th Ed. PP.1007-13. ISBN 0-323-01200-0.
  14. ↑ Croul, SE. 8 November 2010.
  15. ↑ 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.
  16. ↑ 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.
  17. ↑ Prieto VG, Shea CR (July 1999). "Selected cutaneous vascular neoplasms. A review". Dermatol Clin 17 (3): 507–20, viii. PMID 10410855.
  18. ↑ URL: http://www.histopathology-india.net/KS.htm. Accessed on: 31 January 2010.
  19. ↑ 19.0 19.1 Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 23. ISBN 978-1416002741.
  20. ↑ 20.0 20.1 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.
  21. ↑ 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.
  22. ↑ 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.
  23. ↑ 23.0 23.1 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.
  24. ↑ 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.
  25. ↑ 25.0 25.1 25.2 25.3 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.
  26. ↑ URL: http://www.informaworld.com/smpp/723576818-750600/ftinterface~db=all~content=a789166263~fulltext=713240928. Accessed on: 5 May 2010.
  27. ↑ Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 417. ISBN 978-1416002741.
  28. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 643. ISBN 978-0781765275.
  29. ↑ 29.0 29.1 29.2 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.
  30. ↑ 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.
  31. ↑ 31.0 31.1 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.
  32. ↑ 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.
  33. ↑ URL: http://www.ncbi.nlm.nih.gov/omim/300813. Accessed on: 30 May 2010.
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