Bones, Joints, SOFT TISSUES Part 4

Question 1

What are some characteristics of soft tissue tumors?

Answer 1

Non-epithelial tissue neoplasms that usually arise sporadically
- Arise in extremities esp thigh

Question 2

What is a lipoma?

Answer 2

Benign tumor of adipose tissue; soft, mobile, painless, cured by excision

Question 3

What is a liposarcoma?

Answer 3

Common malignant soft tissue tumor that arise esp in the 6th-7th decade

• Often around in deep soft tissue, proximal extremities, and retroperitoneum
• Recur locally unless completely excised

Question 4

What are 3 histological variants of a liposarcoma?

Answer 4

• Well-differentiated (indolent): Mature adipocytes w scattered atypical spindle cells
• Myxoid (intermediate): Abundant basophilic extracellular matrix, arborizing capillaries, primitive cells (resembles fat)
• Pleomorphic (high grade): Sheets of anaplastic cells w bizarre nuclei admixed w variable numbers of immature adipocytes (lipoblasts)

Question 5

What are 3 types of fibrous tumors?

Answer 5

• Nodular fasciitis
• Superficial fibromatoses
• Deep fibromatosis (Desmoid tumor)

Question 6

What are characteristic of a nodular fasciitis?

Answer 6

Self-limited fibroblastic & myofibroblastic proliferation; young adults upper extremity (forearm, chest, back)

• Often d/t hx of trauma
• Rapid growth

Question 7

What are characteristic of a superficial fibromatoses? What are 3 types?

Answer 7

Benign, infiltrative, local deformity

• Palmar fibromatosis (Dupuytren contracture): Nodular thickening of palmar fascia; slowly progressive flexion contracture of 4th and 5th fingers
• Plantar fibromatosis (Ledderhose disease): No contractures
• Penile fibromatosis (Peyronie disease): Palpable induraiton or mass on dorsolateral aspect of penis

Question 8

What are characteristic of a deep fibromatosis (Desmoid tumor)?

Answer 8

Large, infiltrative, freq reoccurrence, NOT metastatic, often

• FAP (Gardner synfrom)
• Abdominal fibromatosis
• Grey-white, firm, poorly demarcated masses 1-15cm in diameter; infiltrate surrounding muscle, nerve, fat

Question 9

What is a rhabdomyosarcoma? What are the 4 subtypes?

Answer 9

Malignant skeletal muscle tumor

• Alveolar: FOXO1 gene fusion to either PAX3 (2;13) or PAX7 (1;13); common in kids
• Embryonal: rhabdomyoblasts, sarocoma botryoides, grape-like mass; common in kids
• Pleomorphic: Myogenin & desmin
• Spindle cell/sclerosing

Question 10

Where do we commonly find rhabdomyosarcoma?

What do we see histologically?

Answer 10

In kids commonly seen in sinuses, head & neck, GU tract
- Aggressive

Histo type and location ae correlated to survival; sarcoma botryoides has most favorable prognosis while pleomorphic is often fatal

Buzz word: Cambium layer on histo

Question 11

What is a leiomyoma?

Answer 11

Benign smooth muscle tumor

• Often found in uterus (aka fibroid)
• Hereditary leiomyomatosis & RCC syndrome

Question 12

What is a leiomyosarcoma?

Answer 12

Malignant painless firm mass

• Tx based on tumor size, location, grade
• IHC smooth muscle proteins including actin, desmin, caldesmon can aid in dx

Question 13

What is a synovial sarcoma?

Answer 13

Actually not a/w synovium, found more commonly in chest wall, head, neck

• Often found in 20-40yos
• • for keratins IHC, epithelial markers

Question 14

What is an undifferentiated pleomorphic sarcoma?

Answer 14

Malignant mesenchymal tumor w high-grade pleomorphic cells

• Most arise in deep soft tissue of extremities, esp in thigh of older adults
• Extrememly pleomorphic w anaplastic spindle or polygonal cells, bizarre nuclei, mitotic figures
• Poor prognosis with metastases common