soft tissue pathology

soft tissue

Expand All | Collapse All

Normal

collagen
myofibroblasts: reactive ones look atypical
vessels: arteries have prominent internal elastica. Veins at most have disorganized adventitial elastic fibers
elastic fibers
fat
skeletal muscle: regenerating skeletal muscle can look atypical

Ddx

round epithelioid
pleomorphic
spindle
vascular
myxoid
lipomatous
Hemorrhagic
Intravascular
- organizing thrombi
- papillary endothelial hyperplasia
- intravascular fasciitis
- spindle cell hemangioma
- epithelioid hemangioma
- epithelioid hemangioendothelioma
- intimal sarcoma
Melanocytic
- clear cell sarcoma
- cellular blue nevus
- paraganglioma-like dermal melanocytic tumor
- PEComa
- pigmented neurofibroma
- melanotic schwannoma
- pigmented neuroectodermal tumor of infancy
- pigmented DFSP
- ossifying fibromyxoid tumor
- myoepithelioma
- myoepithelial carcinoma
bone and cartilage
Sarcoma mimicks
- nodular fasciitis
- other fasciitis
  - intravascular fasciitis
  - cranial fasciitis
  - ischemic fasciitis
  - proliferative fasciitis
- myositis
  - proliferative myositis
  - myositis and panniculitis ossificans
- papillary endothelial hyperplasia
- fibrodysplasia ossificans progressiva
- fibro-osseous pseudotumor of the digits
- localized massive lymphedema
- inflammatory myofibroblastic tumor
Superficial sarcoma
- DFSP
- epithelioid sarcoma
- angiomatoid fibrous histiocytoma
- plexiform fibrohistiocytic tumor
- myxoid undifferentiated pleomorphic sarcoma
- angiosarcoma
- Kaposi sarcoma
- atypical fibroxanthoma

FNCLCC Grading

G1 (low grade): score 2-3
G2 (high grade): score 4-5
G3 (high grade): score 6-8
Scoring (add together)
- type score
  - score 1
    - well-differentiated sarcoma
    - malignant neurofibroma
  - score 2
  - score 3
    - high grade, pleomorphic, poorly differentiated, dedifferentiated sarcoma
    - anything not a grade 1 or 2
- mitosis score (10 HPF/40x mag)
  - score 1: < 10
  - score 2: 10-19
  - score 3: 20+
- necrosis score
  - score 0: none
  - score 1: < 50%
  - score 2: >= 50%

TNM (useful for grossing)

T1: <= 5cm
- T1a: superficial
- T1b: deep
T2: > 5cm
- T2a: superficial
- T2b: deep
superficial
- subcutaneous only
deep
- muscle involvement (includes fascia)
- retroperitoneal
- intraperitoneal/visceral
- intrathoracic
- majority of head/neck tumors

Staging

IA: T1a-b, G1
IB: T2a-b, G1
IIA: T1a-b, G2
IIB: T2a, G2
III: N1 or T2b, G3
IV: M1