Chapter 26: Soft Tissue Flashcards by erin flaherty

Sarcomas with complex karyotypes which are pleomorphic and genetically heterogenous and carry a poor prognosis are most often seen in whom?

Adults

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Most soft tissue tumors are sporadic, but there is a minority that is associated with germline mutations such as what?

Tumor Suppressor gene: NF1, Gardner, Li-Fraumeni, Osler-Weber-Rendu

Environmental exposure: radiation, burns, toxins

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what is the cytogenic abnormality associated with ewing sarcoma family tumors?

t(11;22)(q24;q12)

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A well-encapsulated mass of mature adipocytes that is soft, mobile, and painless arising most commonly in adults is known as what?

Lipoma

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what is lipomatosis?

when multifocal lipomas involve a limb

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what is the histology of a lipoma?

encapsulated mass of normal appearing adipose tissue

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Liposarcoma most often arises in whom and in which locations?

Common malignant ST tumor, adults (50-60 y/o)
Arise in deep ST of prox. extremities and retroperitoneum

-They recur locally repeatedly, unless completely excised

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what are the 3 different histologic variants of a liposarcoma?

well differentiated, myxoid, and pleomorphic

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Which genetic abberations is associated with the myxoid type of liposarcomas?

t(12;16) –> 12q encodes MDM2 a potent inhibitor of p53

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Which genetic abberation is associated with the well-differentiated type of liposarcoma?

12q13-q15 –> 12q encodes MDM2 a potent inhibitor of p53

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What is the morphology of the well-differentiated type of liposarcoma?

Contains mature adipocytes with scattered atypical spindle cells

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What is the morphology of the myxoid type of liposarcoma?

abundant Basophilic myxoid matrix, arborizing capillaries (“chicken-wire”) + primitive cells at various stages of adipocyte differentiation

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Which age group is the myxoid type of liposarcoma most common in and where in the body do they arise?

30 y/o arising in the thigh and leg

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Which translocation is associated with nodular fasciitis?

t(17;22) –> MYH9-USP6 fusion gene

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What is the histology associated with the pleomorphic complex karyotype of liposarcoma?

sheets of anaplastic cells with bizarre nuclei admixed with variable numbers of immature adipocytes= lipoblasts

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What are the 3 classes of fibrous tumors?

nodular fasciitis, superficial fibromatoses, and deep fibromatosis (desmoid tumors)

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What is a self-limited fibroblastic and myofibroblastic proliferation usually seen in young adults in the upper extremity?

nodular fasciitis

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A history of what is seen in some cases of nodular fasciitis?

Trauma

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Whom does nodular fasciitis arise in and in which locations; describe its typical presentation.

Appear in UE’s (arms, forearm) of young adults (20-30 yo)
Grow rapidly over several weeks or months; typically no larger than 5cm

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what is the translocation associated with nodular fasciitis?

t(17;22) → MYH9-USP6 fusion gene = clonal, self-limited, proliferation

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What is the prognosis and tx of nodular fasciitis?

Often spontaneously regress and if excised, rarely recurs

What occurs in the palmar (dupuytren contracture) subtype of superficial fibromatosis?

Irregular or nodular thickening of the palmar fascia; unilateral or bilaterally
Slow progression to flexion contracture, mainly affecting 4th and 5th fingers of hand

Which fibrous soft tissue tumors are large, infiltrative masses that frequently recur, but do not metastasize?

Deep Fibromatosis (Desmoid Tumors)

Patients with what germline mutation and syndrome are predisposed to developing deep fibromatosis (desmoid tumors)?

APC mutations –> familial adenomatous polyposis (FAP) - Gardner syndrome

Which age group and sex most often develop Deep Fibromatosis (desmoid tumors); where do they arise?

- **Women** in **teens** to **30's** - Arise in **anterior abdominal wall** but may also be seen in **limb girdles** or the **mesentery**

Mutations in which 2 genes are associated with Deep Fibromatosis (desmoid tumors)?

***APC*** or CTNNB1 (**β-catenin) ---\>** ↑ **Wnt signaling**

What is the gross appearance of a deep fibromatosis (desmoid tumor)?

gray-white, firm, poorly demarcated masses, 1-15 cm in diameter -they are rubbery and tough and infiltrate surrounding muscle, nerve, and fat

What is the characteristic histologic pattern of Deep Fibromatosis (Desmoid Tumors)?

**Cytologically** _bland_ **fibroblasts** arranged in **broad sweeping fascicles** amid **dense collagen;** histology _resembles_ **scar**

What is the clinical course of Deep Fibromatosis (Desmoid Tumors) and how are they dealt with?

- May be **disfiguring** and **disabling**; may be **_painful_** - Because of **extensive infiltration**, may be _difficult_ to **resect**

What are the most common soft tissue sarcomas of childhood and adolescence?

**Embryonal** and **alveolar** type of **rhabdomyosarcoma**

what are the 4 subtypes of rhabdomyosarcoma?

alveolar. embryonal, pleomorphic, and spindle cell/sclerosing

Where do the pediatric forms of rhabdomyosarcomas most often arise?

**Sinuses**, **head** and **neck**, and **GU tract**

Which genetic aberrations and translocations are associated with alveolar rhabdomyosarcomas?

Fusion of ***FOXO1*** with either ***PAX3*** = **(2;13**) or ***PAX7*** = **(1;13)**

What is the morphology of alveolar rhabdomyosarcomas?

- Networks of **fibrous septae** dividing cells into **clusters** and **aggregates**; centers are **dischohesive** - Resemblance to **pulmonary alveoli** - **Cross striations** are _not_ a **common feature**

What is a subtype of an embryonal rhabdomyosarcoma variant that develops in the walls of hollow, mucosal-lined structures, such as the naso-pharynx, common bile duct, bladder, and vagina?

sarcoma botryoides \*\*\*grape like mass\*\*\*

In sarcoma botryoides, where the tumor cells abut the mucosa of an organ, they form a submucosal zone of hypercellularity called what?

**Cambium layer**

Where does embryonal rhabdomyosarcoma most often arise, characteristic morphology, and age group?

- Arise in **genitourinary tract** - Patients **1-5 y/o** - **Primitive spindle cells**, **_"strap cells_****_"_**

What is tx for rhabdomyosarcoma; which variant has the best and which has the worst prognosis?

- Tx is **surgery** + **chemotherapy**, with or without **radiation** - **Botryoid** variant = **best prognosis** - **Pleomorphic** variant = **worse prognosis**

Phenotype of multiple cutaneous leiomyomas may be transmitted as an **autosomal dominant** trait associated with what?

**Uterine leiomyomas** + **renal cell carcinoma** --\> **hereditary leiomyomatosis** and **renal cell cancer syndorme**

Hereditary leiomyomatosis and renal cell cancer syndorme is due to what mutation and loss of what?

**Germline** loss-of-function mutation in **fumarate hydratase** gene on **1q42.3**

Soft tissue leiomyomas are usually 1-2 cm and are composed of what?

**Fascicles** of _densely_ **eosinophilic** spindle cells that tend to _intersect_ each other at **right angles**

Leiomyosarcomas most often develop in which age group, sex, and structures; common presentation?

- Present as **painless firm masses**, most often in **women** who are **40-60 y/o** - Arise in **deep ST's** of the **extremities** and **retroperitoneum**

Morphology of Leiomyosarcomas?

**Pleomorphic** **eosinophilic** spindle cells w/ **blunt-ended**, hyperchromatic nuclei arranged in **interweaving fascicles**

Leiomyosarcomas arising where are particularly deadly?

Those arising from **great vessels**, especially the **IVC**

Leiomyosarcomas will stain positive for what?

**Antibodies** to **smooth muscle actin** and **desmin and caldesmon**

How does Synovial Sarcoma typically present and in which age group?

Pt's in their **20s-40s** presenting with **deep-seated mass** in **thigh, leg, chest wall** or **head and neck** that has been present for **several years** ***NOT associated with the synovium***

Which characteristic chromosomal translocation is associated with Synovial Sarcomas?

**t(x;18)** producing ***SS18-SSX1, -SSX2,*** *or **-SSX4***

Synovial sarcomas, especially the biphasic type can be differentiated from other sarcoma by (+) immunohistochemical staining for what?

**Epithelial markers** (i.e., **keratin**)

Characteristic morphology of Synovial Sarcoma and how do the monophasic vs. biphasic types differ?

- **Tight fascicles** of **_uniform_** **basophilic spindle cells** - **Biphasic type** also contains **_gland-like structures_**

What is the prognosis of Synovial Sarcomas and where do they metastasize?

- **5-year** of **25%** to **62%** related to **_stage**_ and _**patient age_** - Commonly metz to **lung** and **regional LN's**

What is a malignant mesenchymal tumor with high-grade, pleomorphic cells that cannot be classified into another category by histomorphology, immunophenotype, and genetics?

undifferentiated pleomorphic sarcoma