Soft tissue path

Question 1

Lipoma

Answer 1

• benign tumor of adipose tissue

- most common benign soft tissue tumor in adults

Question 2

Liposarcoma

Answer 2

• malignant tumor of adipose tissue
• most common malignant soft tissue tumor in adults
• lipoblast is the characteristic cell

Question 3

Rhabdomyoma

Answer 3

• benign tumor of skeletal muscle

- cardiac rhabdomyoma is associated with tuberous sclerosis

Question 4

Rhabdomyosarcoma

Answer 4

• malignant tumor of skeletal muscle
• most common malignant soft tissue tumor in children
• Rhabdomyoblast is the charcteristic cell… it’s desmin positive
• most common site is the head and neck; vagina is the classic site in young girls (sarcoma byrtoroides or something like that)

Question 5

genetic abnormality for liposarcoma

Answer 5

• t(12,16)= myxoid
• FUS-DDIT3 fusion gene
• also, amplication of 12q13-15= well differentiated… MDM2 gets amped

Question 6

Nodular fasciitis

Answer 6

• self limited fibroblastic and myofibroblastic proliferation that typically occurs in young adults in the upper extremity
• regresses, rarely recurs
• will be on arm, forearm

Question 7

Superficial fibromatosis

Answer 7

• males
• nodular or poorly defined broad fascicles of fibroblasts in long, sweeping fascicles, surrounded by abundant dense collagen
• if on palm, it’s dupuytren contracture (4th and 5th fingers)
• if on penis: peyronie disease

Question 8

Deep fibromatosis (desmoid tumors)

Answer 8

• large infiltrative masses that frequently recur but do not metastasize
• mutations in APC or B-catenin genes… increased Wnt signaling
• abdominal wall

Question 9

are almost all skeletal muscle tumors malignant?

Answer 9

-yes

Question 10

What does sarcoma botryoides have?

Answer 10

• a cambium layer
• most common
• best prognosis thank goodness!

Question 11

What gene thing is leiomyoma associated with?

Answer 11

-germline LOF mutation in fumarate hydratase gene on chromosome 1q42.3

Question 12

Synovial sarcoma

Answer 12

• it’s only calle dthat because it arose in soft tissues near the knee joint
• but it doesn’t even look anything like synoviocytes
• pt presents with deep-seated mass that has been present for several years

Question 13

What do most synovial sarcomas show as a characteristic chromosomal translocation**

Answer 13

• t(x;18)

- producing SS18-SSX1

Question 14

common sites of mets for synovial sarcomas

Answer 14

-the lung and occasionally the regional lymph nodes

Question 15

Undifferentiated pleomorphic sarcoma (UPS)

Answer 15

• malignant mesenchymal tumors with high-grade, pleomorphic cells that cannot be classified into another category by a combo of histomorphology, immunophenotype, ultrastructure or molecular genetics
• most arise in deep soft tissues of the extremity, exspecially the THIGH OF MIDDLE AGED OR OLDER ADULTS

Question 16

morphology of UPS

Answer 16

• large, gey-white fleshy masses
• necrosis and hemorrhage are common
• large anaplastic spindled to polygonal cellsl with hyperchromatic irregular, sometimes bizzare nuclei
• they look bad…

Question 17

how is the prognosis of UPS?

Answer 17

-poor