Pathology: Soft Tissue Tumors Flashcards
(128 cards)
Definition of soft-tissue tumors
Defined as mesenchymal proliferations that occur in the extraskeletal, nonepithelial tissues of the body, excluding organs, coverings of the brain, and lymphoreticular system.
Classification of soft-tissue tumors
the types of tissue that they recapitulate or differentiate to (e.g. fat, fibrous tissue, muscle, vessels, nerves). In each histogenetic category, they can be divided into benign and malignant (sarcoma) forms.
Soft-tissue tumor locations
Soft-tissue tumors can arise in any location; approximately 40% occur in the lower extremities, 20% in the upper extremities, 10% in the head and neck, and 30% in the trunk and retroperitoneum.
Benign vs malignant soft-tissue tumor prevalence
Benign soft-tissue tumors outnumber malignant soft-tissue tumors by 100:1. Sarcomas are relatively rare, accounting for 0.8% of all invasive malignancies, but 2% of all cancer deaths.
Soft-tissue malignancy metastasize pattern
In contrast to carcinomas, sarcomas usually metastasize via hematogenous routes (e.g. to lung and bone). - rare to lymphnodes
malignant soft-tissue tumor called
sarcoma
type of cell that give rise to soft-tissue tumors
Soft tissue tumors are believed to develop due to mutations in mesenchymal stem cells distributed throughout the body.
State the most common type of genetic abnormality in soft tissue tumors.
translocation –> fusion genes that encode chimeric transcription factors, leading to transcriptional deregulation (uncontrolled cell proliferation).
Other genetic abnormalities result in deregulation of kinase signaling.
Neurofibromatosis Type 1 –>
neurofibroma, malignant peripheral nerve sheath tumor
Gardner Syndrome –>
Fibromatosis
Osler-Weber-Rendu syndrome –>
telangiectasia
Environmental factors implicated in development of soft tissue tumors
Trauma, environmental agents, radiation therapy, viruses, chronic disease
dioxin –>
various sarcomas
vinyl chloride –>
hepatic angiosarocma
post-radiation –>
pleomorphic sarcoma/malignant fibrous histiocytoma, osteosarcoma
HHV8 –>
Kaposi sarcoma
Chronic lymphedema
Angiosarcoma
Some specific types of sarcoma tend to occur in certain _____. In general, incidence of sarcomas increases with ___.
Some specific types of sarcoma tend to occur in certain age groups. In general, incidence of sarcomas increases with age.
Factors that influence prognosis
Histologic classification Histologic grade Stage of tumor Superficial vs. deep Size
Initial morphologic assessment is based on the ____________ of the tumor cells as well as the _______________. Numerous immunohistochemical stains are used in the histologic assessment of some tumors. In some instances, genetic analysis for specific fusion genes can aid in diagnosis.
Initial morphologic assessment is based on the cytologic appearance of the tumor cells as well as the architectural pattern of growth. Numerous immunohistochemical stains are used in the histologic assessment of some tumors. In some instances, genetic analysis for specific fusion genes can aid in diagnosis.
Histologic grade is based on the ______, ___________, and amount of _________
Histologic grade is based on the tumor differentiation score, mitotic count, and amount of tumor necrosis
Staging of soft-tissue sarcomas is based on _________ presence or absence of ___________, and presence or absence of __________. Most sarcoma metastases are ____________.
Staging of soft-tissue sarcomas is based on tumor characteristics (superficial or deep, size less than or greater than 5 cm), presence or absence of lymph node metastases (although lymph node metastases are rare in sarcomas,), and presence or absence of distant metastases (so staging is a T,N,M classification). Most sarcoma metastases are hematogenous.
Tx benign soft-tisue tumors
surgery (simple excision)
soft tissue sarcoma tx
surgery, with radiation therapy and chemotherapy used in certain clinical situations. Sometimes radiation therapy and/or chemotherapy is done before surgical excision (preoperative or neoadjuvant therapy)