Final .20 08-2013.muskuloskeletal system.part4.

Friday, April 14, 2023 1

MUSKULOSKELETAL SYSTEM PART-4.

SOFT TISSUE TUMOURS.SOFT TISSUE TUMOURS.


DEFINITION• Soft-tissue tumours are defined as mesenchymal

proliferations that occur in the extra skeletal, nonepithelial tissues of the body, excluding the viscera, coverings of the brain, and lymphoreticular system.

• They are classified according to the tissue they recapitulate (muscle, fat, fibrous tissue, vessels, and nerves).

• Mesodermal tissues.


Classification 1. Tumour And Tumour Like Lesions Of fibrous Tissue.2. Fibrohistiocytic Tumours,3. Tumours Of Adipose Tissue,4. Skeletal Muscle Tumours.

5. Tumours Of Uncertain Histiogenesis.


Soft Tissue Tumors1. 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


Morphology of Cells in Soft Tissue Tumours. Cell Type Features Tumor Type

Spindle cell Rod-shaped, long axis twice as great as short axis

Fibrous, fibrohistiocytic, smooth muscle, Schwann cell

Small round cell

Size of a lymphocyte with little cytoplasm

Rhabdomyosarcoma, primitive neuroectodermal tumor

Epithelioid Polyhedral with abundant cytoplasm, nucleus is centrally located

Smooth muscle, Schwann cell endothelial, epithelioid sarcoma


Architectural Patterns in Soft-Tissue TumoursPattern Tumour Type

Fascicles of eosinophilic spindle cells intersecting at right angles

Smooth muscle

Short fascicles of spindle cells radiating from a central point like spokes on a wheel- storiform

Fibrohistiocytic

Nuclei arranged in columns-palisading Schwann cell

Herringbone Fibro sarcoma

Mixture of fascicles of spindle cells and groups of epithelioid cells-biphasic

Synovial sarcoma


Introduction• STS are part of a heterogenous group of

mesenchymal neoplasms• Rare - 1% adult, 15% paediatric neoplasms• Can occur at any site Extermities 43% Visceral 19% Retroperitoneal 15% Trunk/thoracic 10% Other 13%• Characterized by their genetic alterations,

morphology under light microscopy and gradeFriday, April 14, 2023 12

• Radiation exposure (osteosarcoma, angiosarcoma)

• Chronic lymphoedema• Trauma• Chemical exposure eg. arsenic, polyvinyl

chloride (hepatic angiosarcoma) • Infections eg. Herpes Human Virus-8: causes

Kaposi’s Sarcoma in immunocompromized patients


Soft Tissue Tumor

Neoplastic conditions arising in extra skeletal mesodermal tissues

-- Skeletal muscle

-- Fibrous tissue-- Smooth muscle

-- Blood & lymphatic vessels-- Peripheral nerves - neuroectoderm

-- Adipose tissue


Soft Tissue TumorGeneral principles for diagnosis:

-- 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-- MalignantFriday, April 14, 2023 15

Soft Tissue Tumors

Histological morphologyImmunohistochemistryCytogenetic studyMolecular analysisUltrastructure

Approach to Diagnosis


Soft Tissue Tumors

Cytokeratin Vimentin Smooth muscle actin Desmin S-100 CD 31 CD 34

Immunohistochemistry


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


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


Nodular Fasciitis


Fibromatosis

Fibroproliferative lesions

Desmoid - Infiltrative masses in abdominal, extra-abdominal & intra-abdominal

Fibroblasts & Myofibroblasts

Palmar, plantar fibromatosis Surgical excision

Infiltrative growth pattern Tendency to recur


Fibromatosis


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 sarcomaFriday, April 14, 2023 23

Fibrosarcoma


Dermatofibroma

Benign fibrous histiocytoma

Usually in skin

Mixture of fibroblasts, myofibroblasts, histiocytesSurgical excision


Dermatofibroma


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 Friday, April 14, 2023 29

Dermatofibrosarcoma Protuberans ( DFSP )


Malignant Fibrous Histiocytoma

Malignant soft tissue tumor with histocytic differentiationMost common type of soft-tissue sarcomaMost common type of soft-tissue sarcomaMost frequently encountered sarcoma post radiation therapyIn adults, in deep soft tissue - extremities & retroperitoneumMarked pleomorphism, spindle cells, storiform, myxoid Friday, April 14, 2023 31

MFH


Leiomyoma

Benign soft tissue tumor

Arising in subcutaneous tissue or blood vessel wall Usually painfull.

Fascicles of regular smooth muscle cells


• Leiomyoma's, the benign smooth muscle tumours, often arise in the uterus; in fact, uterine leiomyoma's are the most common neoplasm in women .

• They develop in 77% of women and, depending on their number, size, and location, may cause a variety of symptoms including infertility


Leiomyoma


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


Leiomyosarcoma


Rhabdomyosarcoma

Malignant tumor of striated muscle differentiation

Most common soft tissue sarcoma in childrens & young adults

Most common soft tissue sarcoma in childrens & young adults Several subtype

1.- Embryonal 2.- Alveolar 3.- Botryoid4.- PleomorphicFriday, April 14, 2023 40

1.Embryonal Rhabdomyosarcoma

Most common in children, in head & neck Most common subtype Rhabdomyoblasts with cytoplasmic cross-striation


Embryonal rhabdomyosarcoma


2.Botryoid Rhabdomyosarcoma

Most common in hollow visceral organs - genitourinary tract

Polypoid, grape-like tumor masses

Scattered malignant cells in myxoid stroma


Botryoid rhabdomyosarcoma


3. Alveolar Rhabdomyosarcoma

In extremities

Fibrous septa with loose clusters of rounded cells in center

- alveolar pattern


Alveolar rhabdomyosarcoma


4. Pleomorphic Rhabdomyosarcoma

In skeletal muscles of older persons, in thigh

Marked pleomorphism

Irregularly arranged cells

Multinucleated giant cells


Pleomorphic Sarcoma


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 In adult, upper back, neck, shoulder

Resemble normal adipose tissue Subtypes:angiolipoma, spindle cell lipoma


Lipoma


Liposarcoma Second most common sarcoma in adults

In deep compartments of extremities & retroperitoneum Lipoblasts Several subtypes- Well differentiated/atypical

lipoma- Myxoid / Round cell- Pleomorphic


Liposarcoma


Hemangioma

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


Angiosarcoma

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


Angiosarcoma


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-100Friday, April 14, 2023 65

Schwannoma


TUMORS OF UNCERTAIN HISTIOGENESIS:• Synovial sarcoma•Alveolar soft part sarcoma•Granular cell myoblastoma.•Epitheloid sarcoma•Clear cell sarcoma•Myositis ossificans


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


Synovial sarcomas are treated aggressively with limb-sparing therapy and frequently chemotherapy.

The 5-year survival varies from 25% to 62%, and only 11% to 30% live for 10 years or longer.

Common sites of metastases are the lung, skeleton, and occasionally the regional lymph nodes.


Synovial sarcoma


mm• Myositis ossficans.• Pseudo malignant osseous tumour of soft

tissues.


• Myositis ossificans is distinguished from the other reactive fibroblastic proliferations by the presence of metaplastic bone.

• It usually develops in athletic adolescents and young adults and follows an episode of trauma in more than 50% of cases.

• The lesion typically arises in the musculature of the proximal extremities.


• Grossly the usual lesion is 3 to 6 cm in greatest dimension and well-demarcated. Initially, the lesion is cellular and consists of plump, elongated fibroblast and myofibroblast-like cells simulating nodular fasciitis .

• In due course these cells are surrounded by an intermediate zone that contains osteoblasts, which deposit ill-defined trabeculae of woven bone


Final .20 08-2013.muskuloskeletal system.part4.

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Transcript of Final .20 08-2013.muskuloskeletal system.part4.