(Nelson) Soft Tissue Tumors Flashcards
What is a Soft Tissue Tumor?
mesenchymal proliferations that occur in the extraskeletal, nonepithelial tissues of the body, excluding organs, coverings of the brain, and lymphoreticular system.
believed to develop due to mutations in mesenchymal stem cells distributed throughout the body.
They are divided into benign and malignant (sarcoma) forms. Benign soft-tissue tumors outnumber malignant soft-tissue tumors by 100:1
Name the clinical manifestation associated with the following genetic syndromes:
**Neurofibromatosis Type 1 **
**Gardner syndrome **
Osler-Weber-Rendu syndrome
Neurofibromatosis Type 1: neurofibroma, malignant peripheral nerve sheath tumor
Gardner syndrome: fibromatosis
Osler-Weber-Rendu syndrome: ** telangiectasia **
What 3 key factors are crucial in determining the prognosis of sarcomas?
- -Histologic classification: morphologic analysis is often complimented by immunohistochemical stains and cytogenetic analysis.
- **-Histologic grade **
- -Stage of the tumor determines both prognosis as well as chance of successful surgical excision.
Describe the staging process of soft-tissue Sarcomas
staging is a T,N,M classification
Tumor description (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
What is a lipoma?
Name & briefly describe the primary subtypes.
Lipomas: Fatty Tumors. Most common soft tissue tumor of adults
- **Conventional lipoma:** most common type, mature fat only
- **Angiolipoma**: mature fat plus small vessel proliferation; can be painful
- **Spindle cell lipoma/Pleomorphic lipoma:** mature fat plus spindle cells/pleomorphic cells
- *Myolipoma:** mature fat plus smooth muscle
- *Chondroid lipoma:** mature fat plus cartilage-like cells
- *Angiomyolipoma**: mature fat plus vessels plus smooth muscle (typically associated with the kidney, and 1/3 occur in patients with tuberous sclerosis)
- *Myelolipoma**: mature fat plus bone marrow elements (usually adrenal gland)
*The first three lipoma types listed above typically occur in a superficial location and are well circumscribed and encapsulated. Some of these benign lipomas are associated with chromosome abnormalities. Treatment is by simple surgical excision.
Name the three morphological types of Liposarcoma
Well-differentiated liposarcoma (relatively indolent, local recurrence, but can be fatal when located in the retroperitoneum); when this tumor occurs in a location amenable to surgical excision (such as an extremity or on the trunk) it may be called an “atypical lipomatous tumor”
Myxoid/round cell liposarcoma (intermediate malignancy)
Pleomorphic liposarcoma (aggressive tumor, frequently metastasizes)
What are reactive pseudosarcomatous proliferations?
Name two types.
non-neoplastic, benign lesions that develop following local trauma/injury or are idiopathic.
1) Nodular Fasciitis: Upper Extrem; Young adults
2) Myositis Ossificans: Adolescent athletes. Margins develop osteoblasts; can become completely ossified.
What are Superficial Fibromatoses?
Name three common examples
Superficial fibromatoses: benign fibroblastic proliferation involving the fascia or aponeuroses (broad tendons); lesions are characterized by nodular or poorly defined broad fascicles of fibroblasts and myofibrobasts surrounded by abundant dense collagen
Palmar fibromatosis (Dupuytren’s contracture): after span of years, the palmar fibrous proliferation can cause skin puckering and progressive flexure contracture.
Plantar fibromatosis: similar process involving the plantar aspect of the foot.
Penile fibromatosis (Peyronie disease): similar process involving the penis.
What are Deep-Seated Fibromatosis (Desmoid Tumors)?
Name three common types.
What type of mutations are most common in them?
Deep-Seated Fibromatosis (Desmoid Tumors):
These tumors consist of an infiltrative, poorly marginated proliferation of bland fibroblasts with collagen. While these lesions do not metastasize, they will recur if incompletely excised. They may occur at any age but are most frequent in the teens to 30’s, and some are associated with a history of previous trauma.
Abdominal Fibromatosis: typically occurs in the musculoaponeurotic structures of the anterior abdominal wall in women during or after pregnancy.
Extra-abdominal Fibromatosis: occurs in men and women with equal frequency and arises principally in the musculature of the shoulder, chest wall, back, and thigh.
***Intra-abdominal Fibromatosis: typically occurs in the mesentery or pelvic side walls, often in individuals having familial adenomatosis polyposis (Gardner syndrome).
Virtually all of the above deep-seated fibromatoses have somatic Beta-catenin or adenomatous polyposis coli (APC) gene mutations.
Fibrosarcoma?
malignant, sarcomatous tumors of fibroblasts.
Fibrohystiocytic Tumors?
contain cellular elements that resemble both fibroblasts and histiocytes (tissue macrophages). As the phenotype of the neoplastic cells most closely resemble fibroblasts, the term fibrohistiocytic should be regarded as a descriptive term, not one indicating the cell of origin.
Rhabdomyoma/Rhabdomyosarcoma?
List 3 subtypes
tumor showing skeletal muscle differentiation
most common soft-tissue sarcoma of childhood and adolescence
** Embryonal rhabdomyosarcoma:** most common subtype (60%); this sarcoma usually occurs in children age 10 years or younger, and often arises in the head and neck (e.g. nasal cavity, orbit, middle ear) and genitourinary tract.
Alveolar rhabdomyosarcoma: this subtype tends to occur in early to middle adolescence, commonly arising in the deep soft-tissues of the extremities, and represents 20% of rhabdomyosarcomas. Specific cytogenetic abnormalities have been identified, some of which connote a worse prognosis; for example, patients with metastatic disease have a four year survival of 75% with a PAX7/FKHR fusion gene vs. only 8% with a PAX3/FKHR fusion gene.
Pleomorphic rhabdomyosarcoma: the rarest of the three subtypes, this sarcoma usually arises in the deep soft-tissues of adults.
What is a leiomyoma/leiomyosarcoma?
tumor showing smooth muscle differentiation
most commonly arise in the uterus, are present in 77% of women, and are often called “uterine fibroids.” They also arise from the arrector pili muscles
Bacillary angiomatosis:
: reactive vascular proliferation resulting from opportunistic infection from Bartonella bacteria in immunocompromised individuals; lesions can occur anywhere in the body, and regress with successful antibiotic therapy.
Angiosarcomas
aggressive, malignant sarcomas showing endothelial differentiation. Older adults are affected, with lesions occurring at any site but often involving skin (head and neck, especially the scalp), soft tissue, breast, and liver. Patients with lymphedema following axillary lymph node resection for breast cancer can get an angiosarcoma which presumably arises in association with dilated lymphatics. Angiosarcomas can also be secondary to previous radiation therapy.
