1. Soft Tissue Tumors Lucy H. Liu, M.D. Department of Pathology
University of Illinois at Chicago

2. UIC College of Medicine M2 Pathology Course, Lecture # 63
Soft Tissue Tumors
UIC College of Medicine
M2 Pathology Course, Lecture # 63
Tuesday, January 28, 2003
11:30 am

3. 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

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

5. Soft Tissue Tumor General principles for diagnosis: Location
-- Deep lesions tend to be malignant
-- Superficial lesions - benign
Size
-- Larger tumors tend to be malignant
Growth pattern
-- Rapidly growing - malignant
-- Infiltrating - malignant
Metastasis
-- Malignant

6. Soft Tissue Tumors Approach to Diagnosis Histological morphology
Immunohistochemistry
Cytogenetic study
Molecular analysis
Ultrastructure

7. Soft Tissue Tumors Immunohistochemistry Cytokeratin Vimentin
Smooth muscle actin
Desmin
S-100
CD 31
CD 34

8. Soft Tissue Tumors Cytogenetic Changes
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

9. Nodular Fasciitis Benign reactive soft tissue lesion
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

10. Nodular Fasciitis

11. Fibromatosis Fibroproliferative lesions Fibroblasts & Myofibroblasts
Infiltrative growth pattern
Tendency to recur
Desmoid - Infiltrative masses
in abdominal, extra-abdominal
& intra-abdominal
Palmar, plantar fibromatosis
Surgical excision

12. Fibromatosis

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

14. Fibrosarcoma

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

16. Dermatofibroma

17. 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

18. Dermatofibrosarcoma Protuberans ( DFSP )

19. Malignant Fibrous Histiocytoma
Malignant soft tissue tumor with
histocytic differentiation
Most common 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

20. MFH

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

22. Leiomyoma

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

24. Leiomyosarcoma

25. Rhabdomyosarcoma Malignant tumor of striated muscle differentiation
In children & young adults
Several subtype
- Embryonal
- Alveolar
- Botryoid
- Pleomorphic

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

28. Embryonal rhabdomyosarcoma

29. Botryoid Rhabdomyosarcoma
Most common in hollow visceral
organs - genitourinary tract
Polypoid, grape-like tumor masses
Scattered malignant cells in myxoid
stroma

30. Botryoid rhabdomyosarcoma

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

32. Alveolar rhabdomyosarcoma

33. Pleomorphic Rhabdomyosarcoma
In skeletal muscles of older
persons, in thigh
Marked pleomorphism
Irregularly arranged cells
Multinucleated giant cells

34. Pleomorphic Sarcoma

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

36. Lipoma

37. Liposarcoma Second most common sarcoma in adults
In deep compartments of extremities
& retroperitoneum
Lipoblasts
Several subtypes
- Well differentiated/atypical lipoma
- Myxoid / Round cell
- Pleomorphic

38. Liposarcoma

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

41. Angiosarcoma Malignant vascular tumor
Many locations: skin, soft tissue,
breast, live, spleen
Irregular channels & atypical
endothelial cells
CD31- endothelial cell marker

42. Angiosarcoma

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

44. Schwannoma

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

46. Synovial sarcoma