SOFT TISSUE TUMORS

1. SOFT TISSUE TUMORS Prof.Dr. Ferda ÖZKAN

2. OBJECTIVES • To define soft tissues • Decribe the types of soft tissue tumors

3. SOFT TISSUE TUMORS Soft tissue tumors are defined as mesenchymal proliferations that occur in the extraskeletal, nonepithelial tissues of the body.

4. SOFT TISSUE TUMORS They are classified according to the tissue they originate such as muscle, fat, fibrous tissue, vessels, and nerves.

5. SOFT TISSUE TUMORS • The cause of most soft tissue tumors is unknown. • The majority of soft tissue tumors occur sporadically, but a small minority is associated with genetic syndromes • neurofibromatosis type 1 (neurofibroma, malignant schwannoma), • Gardner syndrome (fibromatosis), • Li-Fraumeni syndrome (soft tissue sarcoma), • Osler-Weber-Rendu syndrome (telangiectasia)

6. SOFT TISSUE TUMORS There are documented associations, between radiation therapy and rare instances in which chemical burns, thermal burns, or trauma were associated with subsequent development of a sarcoma.

7. SOFT TISSUE TUMORS • Exposure to phenoxyherbicides and chlorophenols has also been implicated in some cases. • Kaposi sarcoma is causally associated with the human herpesvirus 8; (viruses are probably not important in the pathogenesis of most sarcomas)

8. SOFT TISSUE TUMORS Soft tissue tumors may arise in any location, • approximately 40% occur in the lower extremities, especially the thigh; • 20% in the upper extremities; • 10% in the head and neck; • and 30% in the trunk and retroperitoneum. Regarding sarcomas, males are affected more frequently than females , and the incidence generally increases with age.

9. Tumors of adipose tissue Lipomas Liposarcoma Tumors and tumor-like lesions of fibrous tissue Nodular fasciitis, Fibromatoses Superficial fibromatoses Deep fibromatoses Fibrosarcoma Fibrohistiocytic tumors Fibrous histiocytoma Dermatofibrosarcoma protuberans Malignant fibrous histiocytoma Tumors of skeletal muscle Rhabdomyoma Rhabdomyosarcoma Vascular tumors Hemangioma Lymphangioma Hemangioendothelioma Hemangiopericytoma Angiosarcoma Peripheral nerve tumors Neurofibroma Schwannoma Granular cell tumor Malignant peripheral nerve sheath tumors Tumors of uncertain histogenesis Synovial sarcoma Alveolar soft part sarcoma Epithelioid sarcoma SOFT TISSUE TUMORS

10. FATTY TUMORS LIPOMAS • Benign tumors of fat, known as lipomas, are the most common soft tissue tumor of adulthood. • They are subclassified according to particular morphologic features as conventional lipoma, fibrolipoma, angiolipoma, spindle cell lipoma, myelolipoma, and pleomorphic lipoma. • Lipomas are soft, mobile, and painless (except angiolipoma) and are usually cured by simple excision

11. FATTY TUMORS Morphology • The conventional lipoma, the most common subtype, is a well-encapsulated mass of mature adipocytes that varies considerably in size. • It arises in the subcutis of the proximal extremities and trunk, most frequently during mid-adulthood. • Histologically, they consist of mature white fat cells with no pleomorphism.

14. FATTY TUMORS LIPOSARCOMA • Liposarcomas are one of the most common sarcomas of adulthood and appear in those in their forties to sixties, • they are uncommon in children. • They usually arise in the deep soft tissues of the proximal extremities and retroperitoneum and developing into large tumors. • All types of liposarcoma recur locally and often repeatedly unless adequately excised.

15. FATTY TUMORS Morphology • Histologically, liposarcomas can be divided into( atypical lipomatous tumor) well-differentiated, myxoid, round cell, and pleomorphic variants. • Myxoid type is the most common. • The cells in well-differentiated liposarcomas are readily recognized as lipocytes. • In the other variants, most of the tumor cells are not obviously adipogenic, but some cells indicative of fatty differentiation are almost always present. • These cells are known as lipoblasts; they mimic fetal fat cells and contain round clear cytoplasmic vacuoles of lipid that scallop the nucleus.

19. Myxoid liposarcoma

20. TUMORS OF SKELETAL MUSCLE • Skeletal muscle neoplasms, in contrast to other groups of tumors, are almost all malignant. • The benign variant, rhabdomyoma, is distinctly rare.

21. TUMORS OF SKELETAL MUSCLE RHABDOMYOSARCOMA • Rhabdomyosarcoma, the most common soft tissue sarcoma of childhood and adolescence, usually appears before age 20. • They may arise in any anatomic location, but mostly the head and neck or genitourinary tract. • Only in the extremities they appear in relation to skeletal muscle.

22. Rhabdomyosarcoma Age

23. Head-neck 40% Genitourinery 20% Extremities 20% Sites 7% Orbit 28% Head & Neck 11% Trunk 2% Intrathoracic 2% GI-Hepatic 6% Retroperitoneum 18% GU 2% Perineum-Anus 24% Extremities

24. Common Histiotypes of Rhabdomyosarcoma 60% HN-GU 20% Extremities Botryoid 10% Vagina-Grapelike

25. TUMORS OF SKELETAL MUSCLE Morphology • Rhabdomyosarcoma is histologically subclassified into the embryonal, alveolar, and pleomorphic variants. • The rhabdomyoblast-the diagnostic cell in all types-contains eccentric eosinophilic granular cytoplasm rich in thick and thin filaments. • The rhabdomyoblasts may be round or elongate; the latter are known as tadpole or strap cells and may contain cross-striations visible by light microscopy. • Ultrastructurally, rhabdomyoblasts contain sarcomeres, and immunohistochemically they stain with antibodies to the myogenic markers desmin, MYOD1, and myogenin.

27. Rhabdomyosarcoma composed of malignant small round cells. The rhabdomyoblasts are large and round and have abundant eosinophilic cytoplasm; no cross-striations are evident

29. Myogenin Ab-1

30. TUMORS OF SKELETAL MUSCLE • Embryonal rhabdomyosarcoma is the most common type, accounting for 66% of rhabdomyosarcomas. • It includes the sarcoma botryoides described in and spindle cell variants. • The tumor occurs in children under age 10 years and typically arises in the nasal cavity, orbit, middle ear, prostate, and paratesticular region.

31. Embryonal rhabdomyosarcoma

32. Embryonal rhabdomyosarcoma

33. TUMORS OF SKELETAL MUSCLE • Alveolar rhabdomyosarcoma is most common in early to mid-adolescence and usually arises in the deep musculature of the extremities. • Histologically the tumor is traversed by a network of fibrous septae that divide the cells into clusters or aggregates; as the central cells degenerate and drop out, with resemblance to pulmonary alveolae.

34. Alveolar rhabdomyosarcoma

35. Alveolar rhabdomyosarcoma with numerous spaces lined by tumor cells

36. TUMORS OF SKELETAL MUSCLE • Pleomorphic rhabdomyosarcoma is characterized by numerous large, sometimes multinucleated, bizarre eosinophilic tumor cells. • This variant is rare, has a tendency to arise in the deep soft tissue of adults and, as noted earlier, can resemble malignant fibrous histiocytoma histologically.

37. TUMORS OF SKELETAL MUSCLE • Rhabdomyosarcomas are aggressive neoplasms and are usually treated with a combination of surgery and chemotherapy with or without radiation. • The histologic variant and location of the tumor influence survival. • The botryoid subtype has the best prognosis, followed by the embryonal, pleomorphic, and alveolar variants. • Overall, approximately 65% of children are cured of their disease, but adults fare less well.

38. TUMORS OF SMOOTH MUSCLE LEIOMYOMA • Leiomyomas, the benign smooth muscle tumors, often arise in the uterus where they represent the most common neoplasm in women • Leiomyomas may also arise in the erector pili muscles found in the skin, nipples, scrotum, and labia (genital leiomyomas) and less frequently develop in the deep soft tissues.

39. TUMORS OF SMOOTH MUSCLE • They are usually not larger than 1 to 2 cm in greatest dimension and are composed of fascicles of spindle cells that tend to intersect each other at right angles. • The tumor cells have blunt-ended, elongated nuclei and show minimal atypia and few mitotic figures. • Solitary lesions are easily cured; however, they may be so numerous that complete surgical removal is impractical.

43. TUMORS OF SMOOTH MUSCLE LEIOMYOSARCOMA • Leiomyosarcomas account for 10% to 20% of soft tissue sarcomas. • They occur in adults and afflict women more frequently than men. • Most develop in the skin and deep soft tissues of the extremities and retroperitoneum.

44. TUMORS OF SMOOTH MUSCLE Morphology • Leiomyosarcomas present as pain-less firm masses. • Retroperitoneal tumors may be large and bulky and cause abdominal symptoms. • Histologically, they are characterized by malignant spindle cells that have cigar-shaped nuclei arranged in interweaving fascicles. Morphologic variants include tumors with a prominent myxoid stroma and others with epithelioid cells. • Immunohistochemically, they stain with antibodies to vimentin, actin, smooth muscle actin, and desmin.

45. TUMORS OF SMOOTH MUSCLE • Treatment depends on the size, location, and grade of the tumor. • Superficial or cutaneous leiomyosarcomas are usually small and have a good prognosis, • large, retroperitoneal ones cannot be entirely excised, and cause death by both local extension and metastatic spread.

49. FIBROHISTIOCYTIC TUMORS • Fibrohistiocytic tumors contain cellular elements that resemble both fibroblasts and histiocytes.

50. FIBROHISTIOCYTIC TUMORS BENIGN FIBROUS HISTIOCYTOMA (DERMATOFIBROMA) • Benign fibrous histiocytoma is a relatively common lesion that usually occurs in the dermis and subcutis. • It is painless and slow growing and most often presents in mid-adult life as a firm, small (up to 1 cm) mobile nodule.