Soft tissue tumor

1. Soft Tissue Tumors
Yi-Che,William, Chang Chien, MD, PhD

2. Soft Tissue Tumors
Lecture Goals:
1. Nomenclature & classification system of tumors
2. Differences between benign and malignant tumors
3. Clinical & morphologic features of common tumors
4. Approach to diagnosis of soft tissue tumors

3. 257
2010
2019

4. • Rare: 50/million, 1% of all cancers (in the US)
• >257 subtypes by WHO classification
• Can arise virtually anywhere
• skin, subcutis, deep soft tissue
• organs (i.e. non soft tissue sites)
• Seen in general surgical pathology practice
• Can mimic
• carcinoma
• lymphoma
• melanoma
Epidemiology of Soft Tissue Tumor:

5. Soft Tissue Tumor
Neoplastic conditions arising in
extraskeletal mesodermal tissues
-- Skeletal muscle
-- Fibrous tissue
-- Smooth muscle
-- Blood & lymphatic vessels
-- Peripheral nerves - neuroectoderm
-- Adipose tissue

6. Soft Tissue Tumor
General principles for diagnosis (Not Always!!):
-- Deep lesions tend to be malignant
-- Larger tumors tend to be malignant
 Location
 Size
-- Superficial lesions - benign
-- Rapidly growing - malignant
 Growth pattern
-- Infiltrating - malignant
 Metastasis
-- Malignant

7. Soft Tissue Tumors
Histological morphology
Immunohistochemistry
Molecular analysis
Ultrastructure (rarely used nowadays)
Approach to Diagnosis

8. Soft Tissue Tumors
Cytokeratin (ca.?)
 Vimentin (not ca.?)
 Smooth muscle actin
 Desmin (myogenic?)
 S-100 (neurogenic?)
 CD 31 (vasculogenic ?)
 CD 34 (whatever…)
Immunohistochemistry

9. Soft Tissue Tumors
 t( 2:13) Alveolar rhabdomyosarcoma
 t( 11;22) Ewing’s sarcoma/PNET
 t( 11;22) Desmoplastic small round cell tumor
 t( 12;16) Myxoid liposarcoma
 t( 9;22) Myxoid chondrosarcoma
 t(12;22) Clear cell sarcoma
 t( X;18) Synovial sarcoma
Cytogenetic Changes

10. STT Nomenclature:

11. FNCLCC Grading System
Fe´de´ration Nationale des Centres de Lutte le Cancer
Jean-Michel Coindre: Grading of Soft Tissue Sarcomas; Review and Update, Arch Pathol Lab Med. 2006;130:1448–1453

12. Staging:
American Joint Committee on Cancer (AJCC )
of soft tissue sarcomas classification(8 ed.)

13. Nodular Fasciitis
 Probably secondary to trauma
 On forearm, trunk, back- well circumscribed
 Spindle cells ( fibroblasts & myofibroblasts)
in loose matrix -“fibroblasts in tissue culture”
 Rapid growth, frequent mitotic figures
 Self-limited, cured by excision
 Must differentiate from a sarcoma
USP6 gene translocation identified
(neoplastic).

14. Nodular Fasciitis

15. Fibromatosis
 Fibroproliferative lesions
 Desmoid - Infiltrative masses
in abdominal, extra-abdominal
& intra-abdominal
 Fibroblasts & Myofibroblasts
 Palmar, plantar fibromatosis
 Surgical excision
Beta-catenin/ AFP gene mutation
 Infiltrative growth pattern
 Tendency to recur

16. Fibromatosis

17. Fibrosarcoma
 Malignant tumor of fibroblast origin
 In adults, in lower extremities,
upper extremities, trunk
 Increased cellularity, high
nuclear-cytoplasmic ratios
 Spindle cells in a herringbone pattern
 Must exclude other tumors which
resemble fibrosarcoma
- Peripheral nerve sheath tumor
- Synovial sarcoma

18. Fibrosarcoma

19. Dermatofibroma
Benign fibrous histiocytoma
Usually in skin
Mixture of fibroblasts,
myofibroblasts, histiocytes
Surgical excision

20. Dermatofibroma

21. Dermatofibrosarcoma
Protuberans (DFSP)
Fibrohistiocytic tumor
 Intermediate malignant potential
 In skin & subcutis
 Spindle cells in storiform pattern
 Local recurrence
 CD 34
 Transformation to fibrosarcoma
 Surgical excision

22. Dermatofibrosarcoma Protuberans ( DFSP )

23. Undifferentiated Pleomorphic
Sarcoma (MFH)
Malignant soft tissue tumor without
specific lineage differentiation
Rare type of soft-tissue sarcoma
Most frequently encountered sarcoma
post radiation therapy
In adults, in deep soft tissue
- extremities & retroperitoneum
Marked pleomorphism, spindle cells,
storiform, myxoid

24. MFH

25. Leiomyoma
 Benign soft tissue tumor
 Arising in subcutaneous tissue
or blood vessel wall
 Usually painful
 Fascicles of regular smooth muscle cells

26. Leiomyoma

27. Leiomyosarcoma
 Malignant soft tissue tumor
 Arising in extremities of blood
vessel wall
 Necrosis, hemorrhage
 Fascicles, nuclear atypia
 High mitotic activity

28. Leiomyosarcoma

29. Rhabdomyosarcoma
 Malignant tumor of striated muscle
differentiation
 In children & young adults
 Several subtype
- Embryonal (Botryoid)
- Alveolar
- Pleomorphic
-Spindle/Sclerotic
-Epithelioid

30. Embryonal
Rhabdomyosarcoma
 Most common in children,
in head & neck
 Most common subtype
 Rhabdomyoblasts with
cytoplasmic cross-striation

31. Embryonal rhabdomyosarcoma

32. Alveolar
Rhabdomyosarcoma
 In extremities
 Fibrous septa with loose clusters of
rounded cells in center
- alveolar pattern

33. Alveolar rhabdomyosarcoma

34. Lipoma
 Benign, well-circumscribed tumor of
well-differentiated adipocytes
 Usually subcutaneous, any site of
adipose tissue
 Most common type of benign soft
tissue tumor
 In adult, upper back, neck, shoulder
 Resemble normal adipose tissue
 Subtypes:angiolipoma, spindle cell lipoma

35. Lipoma

36. Liposarcoma
 Second most common sarcoma in adults
 In deep compartments of extremities
& retroperitoneum
 Lipoblasts
 Several subtypes
- Well differentiated/atypical lipomatous tumor
-Dedifferentiated
- Myxoid
- Pleomorphic

37. Liposarcoma

38. Hemangioma
 Benign lesion
 Resemble normal blood vessels
 Congenital or non-congenital
 Most common in infants & children
 Head & neck, internal organs - liver

40. Angiosarcoma
 Malignant vascular tumor
 Many locations: skin, soft tissue,
breast, live, spleen
 Irregular channels & atypical
endothelial cells
 CD31, CD34, ERG Fli1+

41. Angiosarcoma

42. Nerve Sheath Tumours

43. Schwannoma
 Benign tumor of neural differentiation
- Schwann cells
 Antoni A
 Antoni B
 In association with large nerve trunks
 Head & neck, extremities
-- Cellular area, palisaded nuclei
-- Less cellular area, myxoid background
 S-100

44. Schwannoma

45. Synovium
membrane

46. Synovial sarcoma
 Malignant soft tissue tumor
 Arising in region of a joint
& other sites of deep soft tissue
 Unknown origin- misnomer !!
 Multilobular
 Biphasic pattern
- spindle cells
- epithelial - like cells
 t( X;18 )

47. Synovial sarcoma