Soft Tissue Tumors: Types, Diagnosis, and Prognosis

1. Soft Tissue Tumors

2. Definition of soft tissue • Nonepithelial extraskeletal tissue fat, fibrous tissue, vessels, muscles, peripheral nerves

3. Histologic classification • Classified by type of tissue formed by the tumor

6. Incidence • Benign : malignant = 100 : 1 • Less than 1% of all malignant tumors • 2% of all cancer death • Insignificant geographic differences

7. Clinical • Behaviour :Benign, intermediate, malignant • Age : more common in older persons • 15% is less than 15 years of age • Sex : M:F = 1.4:1

8. Location • 40% lower extremity (thigh) • 30% trunk and retroperitoneum • 20% upper extremity • 10% head and neck

9. Prognosis • HISTOLOGY Grade - mitoses/hpf, pleomorphism, extent of necrosis • Staging : TNM system • Size and depth (superficial or deep-seated)

10. Pathogenesis • Most are unknown, occur sporadically

11. Pathogenesis • Post-radiation sarcoma • Oncogenic viruses • Immunodeficiency

12. Genetic susceptibility • Inherited cancer syndromes (tumor suppressor genes) • Neurofibromatosis I - ~ 2% MPNST • Li-Fraumeni syndrome – p53 gene-various tumours

13. Histologic diagnosis • Cell morphology : spindle cell, small round cell, epithelioid cell • Architectural arrangement : fascicles with right angle intersection, storiform (spoke wheel), herring-bone, nuclear palisading, biphasic

14. Diagnosis • In poorly differentiated high grade sarcoma, other studies required • Immunohistochemistry • EM • Cytogenetics • Molecular genetics

15. Lipoma • Benign tumor of fat cell (benign lipomatous tumor) • Most common tumor of adulthood • Clinical • Asymptomatic, slow growing tumor, round or discoid mass, soft to firm consistency, painless solitary or multiple

16. Lipoma • Gross • Well-encapsulation of mature adipocytes • Location : subcutis of proximal extremities and trunk • Histology : Capsule Mature adipocytes

17. Variants • fibrolipoma, • angiolipoma, • spindle cell lipoma, • myxolipoma, • myolipoma, • pleomorphic lipoma, • angiomyolipoma, • chondrolipoma, • osteolipoma, • intramuscular and intermuscular lipomas

19. Lipoma

20. Angiolipoma

21. Intramuscular lipoma

22. Liposarcoma • Tumor of adult life, 40-60 yrs • Originated from primitive mesenchymal cell • Location • Thigh and peritoneum (80%) • Upper extremity, head and neck

23. Liposarcoma • Gross • Tend to be well-circumscribed or encapsulated, may form satellite nodules • Cut surface vary depending on histologic type, necrosis, hemorrhage, cyst • Yellow to white or gray-white in color

24. Liposarcoma • Atypical lipomatous tomour/well-differentiated liposarcoma • Myxoid liposarcoma /Round cell liposarcoma • Pleomorphic liposarcoma • Dedifferentiated liposarcoma

25. Microscopy : LIPOBLASTS! round clear cytoplasmic vacuoles that scallop the nucleus

26. Well differentiated liposarcoma

27. Well differentiated liposarcoma

29. Myxoid liposarcoma

30. Myxoid liposarcoma

31. Pleomorphic liposarcoma

32. Fibroblastic/Myofibroblastic tumors Benign Nodular fasciitis Intermediate Dermatofibrosarcoma protuberans Adult-type Fibromatosis • Superficial (palmar,plantar) • Deep ( desmoid-extraabdominal,abdominal) Malignant fibrosarcoma

33. Dermatofibrosarcoma protuberans • Common, low-grade sarcoma • Slow growing nodular cutaneous and subcutaneous mass in early or mid-adult life • Most common on trunk and proximal extremities, head and neck

34. Dermatofibrosarcoma protuberans • Histology • Look like dermatofibroma but more infiltrative • Uniform slender fibroblasts arranged in distinct storiform pattern with low to moderate mitosis

35. Dermatofibrosarcoma protuberans

36. Fibromatoses • Superficial fibromatoses • Palmar fibromatosis (Dupuytren contracture) • Irregular and nodular thickening of palmar fascia • Unilateral or bilateral  flexion deformity of 4th and 5th fingers • Plantar fibromatosis

37. Fibromatoses • Histology : nodular, poorly defined fascicles of mature fibroblast(myofibroblast) with dense collagen • Prognosis : may stable, regress or recur

38. Palmar fibromatosis

40. Fibromatoses • Extraabdominal desmoid • Most common • Shoulder, pelvic girdle, thigh of adolescents and young adults • Abdominal desmoid • Anterior abdominal wall in woman during or after pregnancy (20-30 yrs)

41. Fibrosarcoma • Rare • Aggressive tumor : 50% recur, 25% metastasis • Infantile fibrosarcoma – favorable prognosis • Retroperitoneum, thigh, knee • Gross : unencapsulated, infiltrative soft, fish-flesh mass with areas of hemorrhage and necrosis

42. Fibrosarcoma • Histology • Well differentiated to poorly differentiated • Malignant spindle cells arranged in herring-bone pattern

43. Fibrosarcoma

44. Benign fibrous histiocytoma • more common Cutaneous fibrous histiocytoma (dermatofibroma) – • Nodular mass in dermis or subcutis, slow growing up to 1 cm. in diameter • Most common on skin of extremities of early and mid-adult life

45. Benign fibrous histiocytoma • Histology • Proliferation of bland spindle cells arranged in storiform pattern (dermatofibroma)

46. Dermatofibroma

47. Dermatofibroma

48. Malignant fibrous histiocytoma • late adult life • Arising in extremities, retroperitoneum

49. Malignant fibrous histiocytoma(pleomorphic undifferentiated sarcoma • Subtypes - stoiform/pleomorphic MFH - myxoid MFH • Giant cell MFH • Inflammatory MFH

50. Pleomorphic MFH • Most common subtype • Gross : unencapsulated large mass (up to 20 cm.) with areas of hemorrhage & necrosis • Histo : malignant spindle cells arranged in storiform pattern with scattered large round pleomorphic cells