MSK Pathology 8 Soft Tissue Tumors

What tests are helpful in making a synovial sarcoma diagnosis? What are synovial sarcomas positive for?

ImmunoHistoChemistry IHC tests are helpful in making the correct diagnosis, Synovial Sarcomas are positive for Epithelial Membrane Antigen & Cytokeratin.

Identify

Large, round with abundant granular eosinophilic cytoplasm. May be round or elongated - known as tadpole or strap cells.

What factors are related to development of soft tissue tumors

Most are sporadic Some from burns, radiation, or toxin exposure. Kaposi sarcoma from HSV 8 Genetic syndromes -1. Neurofibromatosis type 1. 2. Gardner syndrome. 3. Li-Fraumeni Syndrome. 4. Osler -Weber- Rendu Syndrome

Rhabdomyosarcoma

Most common soft tissue sarcoma of childhood - appears <20 years. Occur in head, neck, genitourinary tract where there is little skeletal muscle

What are multiple leiomyoma's assoc with and what do the predispose the patient to?

Multiple leiomyoma's can be associated with germline mutation, and predispose to development of renal cell carcinoma.

Synovial Sarcoma: Occurrence, Tx and Location of metastisis

Occurs in 20-40 yo. in deep soft tissue, usually lower extremities but also head, neck and viscera. Treated aggressively with limb-sparing surgery and chemotherapy. Metastisize to LUNG, BONE, and Regional LYMPHNODES. Only 10-30% survive more than 10 yrs

Nodular Fasciitis

aka pseudosarcoma - self-limited, reactive Nodular fibroblastic proliferation. Adults, forearm, chest & back. Rapidly growing, occasionally painfull mass, preceding history of trauma. Rarely recur after excision.

What is the prognosis of a liposarcoma?

• Well differentiated liposarcoma are low grade tumors, assoc with EXCELLENT prognosis. • Round cell type & Myxoid Liposarcoma type are intermediate in its malignant behavior. • Pleomorphic type Liposarcoms is aggressive and frequently metastasize.

What four aspects of a soft tissue tumor influence prognosis?

1. Accurate histological classification: Must include immunohistochemistry, electronmicroscopy, cytogenica and molecular genetics. 2. Grading to predict behavior: I-III based on the degree of differentiation, number of mitosis, cellularity, pleomorphysim, extent of necrosis ( growth). 3. Staging for prognosis-tumor larger than 20cm -80% metastasize, tumor less than 5cm-30% metastasize. 4. Tumors in superficial locations (skin) = better prognosis than deep seated tumors.

Identify. What would be your DDX?

1.organized hematoma, 2.connective tissue metaplasia, 3. chipping of osteoblast and periosteum wandering across periosteal gaps. • DDX Rhabdomyosarcoma, Extra- Skeletal Osteosarcoma.

Histologically synovial sarcoma are classified in to what two types?

biphasic and monophasic Classic biphasic differentiation into epithelial-like cells & spindle cells Monophasic - spindle cells or epithelial cells (rare) only. Lesions composed solely of spindled cells are easily mistaken for Fibrosarcoma, or Malignant Peripheral Nerve Sheet Tumour.

Leiomyoma

Benign smooth muscle tumors often arise in the uterus, from erector pili muscle in the myometrium, deep soft tissue and the wall of gut. Often referred to as fibroids.

Lipoma - Classification, Clinical presentation and Histology

Benign tumors of adipose tissue - most common STT. of adulthood. Solitary, but can be multiple. Histopathology: conventional, myolipoma, spindle cell, pleomorphic, angiolipoma (painfull variant). Clinical feature - Mobile, slowly enlarging, painless.

Soft tissue tumors include tumors of

fat, fibrous tissue and neuromuscular tissue

What are the translocations that are found in Rhabdo?

t(2;13) which fuses the PAX3 gene on chrom 2 with the FKHR gene on chrom 13.

Most synovial sarcoms show what translocation?

t(X; 18) translocation: produces a SYT gene + either SSX1 or SSX2 gene

Histology is similar to others so what is important to exclude when considering

Fibromatosis And Spindle Cell Sarcomas.

Identify

Fibrosarcoma composed of malignant spindle cells arranged in a herringbone pattern. All degrees of differentiation, from tumors that closely resemble fibromatosis, to densely packed lesions with spindled cells growing in a herringbone fashion, to highly cellular neoplasms exhibiting architectural disarray, pleomorphism, frequent mitosis, and necrosis.

Leiomyosarcoma Histology

Histologically they show spindle cells, with cigar-shaped nuclei arranged in interweaving fascicles.

A Fibrosarcoma is a malignant neoplasm composed of what? What is the prognosis and where are the found?

Malignant neoplasm composed of fibroblasts. Slowly growing but aggressive tumours recurring in more than 50% of cases & metastasizing in more than 25% . Most tumors occur in adults, in deep tissue of thigh, knee, and retroperitoneal area

identify

Myxoid liposarcoma with abundant ground substance in which are scattered adult-appearing fat cells and more primitive cells, some containing small lipid vacuoles (lipoblasts).

Identify

Nodular Fasciitis - highly cellular lesion composed of plump, randomly oriented spindle cells surrounded by myxoid stroma. +/- inflammatory cells and extravasated RBC. Mitotic figure are abundant.

What are the three categories of fibrous tumors and tumor like lesions?

Nodular fasciitis, fibromatoses, and fibrosarcomas

Leiomyosarcoma: Affects who and where? How does it present and what unusual symptoms do they cause?

Occur in adult, more common in females, affect skin, deep soft tissue of the extremities and retro- peritoneum. Present as firm, painless masses; retroperitoneal tumors can be large & bulky and cause abdominal symptoms. Treatment depends on size, location and grade.

Liposarcoma: What are the cells called and what form of tumor is it? Where does it arise and how does it present?

a malignant neoplasm of adipocyte, the tumor cells are called LIPOBLASTS. Most arise in deep soft tissue of proximal extremities & retroperitonium. Present as well- circumscribed soft, mass of long duration. In 5-6th decade

Leiomyoma Histology

Spindle cells with blunt ended, elongated nuclei with minimal atypia & rare mitosis.

Most liposarcoma's contain what? What does that region contain?

A supernumerary ring and giant rod chromosome. Due to amplification of 12q14 and 12q15 Contains the MDM2 oncogene which inhibits P53

What chromosomal translocation is common in Myxoid and round cell type of liposarcoma?

A t(12;16) chromosomal translocation which affects transcription factor

What are the histological variants of Rhabdomyosarcoma? What is the diagnostic cell in all variants and what myogeneic markers will they be positive for?

Embryonal, alveolar, pleomorphic Rhabdomyoblast is the diagnostic cell Desmin, MYOD1, and Myogenin

In what diseases of soft tissue can chromosomal abnormalities tell about the pathogenesis?

Ewing sarcoma & Synovial sarcomas

Histology of fibrosarcoma

F.S. are soft un- encapsulated, infiltrative masses with areas of haemorrhage and necrosis. Better differentiated lesions can appear deceptively encapsulated.