Chapter 26: Soft Tissue Flashcards

1
Q

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

A

Adults

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2
Q

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

A

Lipoma

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3
Q

Liposarcoma most often arises in whom and in which locations?

A
  • Common malignant ST tumor, adults (50-60 y/o)
  • Arise in deep ST of prox. extremities and retroperitoneum
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4
Q

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

A

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

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5
Q

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

A

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

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6
Q

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

A

Contains adipocytes with scattered atypical spindle cells

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7
Q

What is the morphology of the myxoid type of liposarcoma?

A

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

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8
Q

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

A

30 y/o arising in the thigh and leg

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9
Q

Which translocation is associated with nodular fasciitis?

A

t(17;22) –> MYH9-USP6 fusion gene

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10
Q

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

A

Trauma

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11
Q

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

A
  • 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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12
Q

What is the prognosis and tx of nodular fasciitis?

A

Often spontaneously regress and if excised, rarely recurs

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13
Q

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

A
  • Irregular or nodular thickening of the palmar fascia; unilateral or bilaterally
  • Slow progression to flexion contracture, mainly affecting 4th and 5th fingers of hand
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14
Q

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

A

Deep Fibromatosis (Desmoid Tumors)

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15
Q

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

A

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

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16
Q

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

A
  • Women in teens to 30’s
  • Arise in anterior abdominal wall but may also be seen in limb girdles or the mesentery
17
Q

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

A

APC or β-catenin —>Wnt signaling

18
Q

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

A

Cytologically bland fibroblasts arranged in broad sweeping fascicles amid dense collagen; histology resembles scar

19
Q

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

A
  • May be disfiguring and disabling; may be painful
  • Because of extensive infiltration, may be difficult to resect
20
Q

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

A

Embryonal and alveolar type of rhabdomyosarcoma

21
Q

Where do the pediatric forms of rhabdomyosarcomas most often arise?

A

Siuses, head and neck, and GU tract

22
Q

Which genetic aberrations and translocations are associated with alveolar rhabdomyosarcomas?

A

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

23
Q

What is the morphology of alveolar rhabdomyosarcomas?

A
  • Networks of fibrous septae dividing cells into clusters and aggregates; centers are dischohesive
  • Resemblance to pulmonary alveoli
  • Cross striations are not a common feature
24
Q

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

A

Cambium layer

25
Q

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

A
  • Arise in genitourinary tract
  • Patients 1-5 y/o
  • Primitive spindle cells, “strap cells
26
Q

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

A
  • Tx is surgery + chemotherapy, with or without radiation
  • Botryoid variant = best prognosis
  • Pleomorphic variant = worse prognosis
27
Q

Phenotype of multiple cutaneos leiomuomas may be transmitted as an autosomal dominant trait associated with what?

A

Uterine leiomyomas + renal cell carcinoma –> hereditary leiomyomatosis and renal cell cancer syndorme

28
Q

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

A

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

29
Q

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

A

Fascicles of densely eosinophilic spindle cells that tend to intersect each other at right angles

30
Q

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

A
  • 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
31
Q

Morphology of Leiomyosarcomas?

A

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

32
Q

Leiomyosarcomas arising where are particularly deadly?

A

Those arising from great vessels, especially the IVC

33
Q

Leiomyosarcomas will stain positive for what?

A

Antibodies to smooth muscle actin and desmin

34
Q

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

A

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

35
Q

Which characteristic chromosomal translocation is associated with Synovial Sarcomas?

A

t(x;18)(p11;q11) producing SS18-SSX1, -SSX2, or -SSX4

36
Q

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

A

Epithelial markers (i.e., keratin)

37
Q

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

A
  • Tight fascicles of uniform basophilic spindle cells
  • Biphasic type also contains gland-like structures
38
Q

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

A
  • 5-year of 25% to 62% related to stage** and **patient age
  • Commonly metz to lung and regional LN’s