Pathology of Bone and Soft tissue - Akalin Flashcards
Although the cause of a soft tissue tumor might be unknown, what are the associated factors that are thought to be part of the cause?
Genetic syndromes
Exposures to chemicals - eg thorotrast, vinyl chrolide, arsenic
Burns
Radiation
Sarcomas metastasze through which route?
What is their common site of metastasis?
They commonly metastasize through the hematogenous route
The common site of metastasis is the lungs
What are the predictors of behaviour of soft tissue tumors?
Cytologic appearence
- Small round blue cells
- Spindle cells
- Epithiliod cells
- Pleomorphic cells
Growth pattern
- Storiform
- Palisading
- Intersecting bundles
- Herringbone
Ancillary studies
- Immunohistological stains
- Cytogenetic and molecular studies
- Electron microscopy
Cytokeratins are a marker for which sarcoma?
And how is this unique
Cytokeratins are a marker for synovial sarcoma
This is unique because cytokeratins are a carcinoma marker
This sarcoma acts a little bit weired. If you are expecting a sarcoma but you have positive cytokeratin (a carcinoma marker) then its synovial sarcoma - EXAM QUESTION
What is the cytogenetic abnormality associated with Ewing sarcoma/primitive neuroectodermal tumor?
t(11;22)(q24;12) - classic one, but there is more
What is the cytogenetic abnormality associated with Synovial sarcoma?
t(X;18)(p11;q11)
Clinically what is used to predict tumor behaviour?
Histologic grade
Stage
Resection margins
** In general tumors arising in the supeficial location have a better prognosis than deep seated lesions
What is a lipoma?
Where is it mostly seen?
Describe it grossly.
A benign uniform proliferation of mature adipocytes.
Most common soft tissue tumors of adults.
It commonly arises in the subcutis of proximal extremities and trunk. However, it can be seen anywhere both superficial and deep soft tissues.
Soft, mobile, painless (except angiolipoma) lesions.
Gross exam: Well-circumscribed mass with yellow cut surface.
What is liposarcoma
Location?
What is the key diagnostic factor?
Describe the tumor grossly
One of the most common sarcoma of adults
Usually arises in the deep soft tissue of the proxima extremities and retroperitoneum, forming large masses
There are four histologic variants are recognized
Key to diagnosis - lipoblasts in the tissue sections
lipoblast - contains round clear cytoplasm vacuoles of lipid that scallop the nucleus
Large multinodular mass with yellow cut surface. Some admixed white or gelatinous ares may be seen
What is superficial fibromatosis?
What are the examples of superficial fibromatosis and in whom are they mroe common in?
M/F?
• Broad group of benign, infiltrative fibrosing proliferations of soft tissues.
• Different names depending on the location involved:
– Palmar fibromatosis (Dupuytren’s contacture): 1-2% of white population), ~50% bilateral palms.
– Plantar fibromatosis (Ledderhose’s disease)
– Penile fibromatosis (Peyronie’s disease)
• Mainly affects adults.
– For unknown reasons, palmar fibromatosis most commonly occur in Northern Europeans.
– Plantar fibromatosis is more common in children and adolescents
• More common in males (M:F ratio 3-4:1).
- Slow and insidious onset
- Palpable cord-like nodularity
- After years, attachement to skin causes puckering and dimpling
- Flexion contracture develops mainly affecting fourth and fifth fingers (palmar fibromatosis)
- Palpable mass on the dorsolateral aspect of the penis appears in penile fibromatosis, eventually leading to abnormal curvature of the shaft, cconstriction of the urethra, or both
Describe superficial fibromatosis
Gross?
Histology?
Gross examination:
- Usually single, small nodule <2 cm),
- Sometimes multiple.
- Firm gray-yellow-white cut surface based on the amount of collagen present.
Histology:
–Monotonous, fascicular lesion composed of nonatypical fibroblasts in a collagenous background.
–Infiltration into overlying subcutaneous tissue often prominent.
–Mitotic figures may be seen but no atypical mitosis.
–No nuclear hyperchromasia, pleomorphism and necrosis.
Deep seated fibromatosis
Also known as?
Most common locations
Also known as desmoid tumors.
Rapidly growing, deeply-situated, infiltrative and locally aggressive fibroblastic/myofibroblastic neoplasm that tends to recur but do not metastasize.
Most common locations:
Intra-abdominal (mesentery, pelvic walls): usually in individuals with familial adenomatous polyposis (Gardner syndrome)
Abdominal wall: usually women, during and after pregnancy.
Extra-abdominal (chest wall, shoulder, back, thigh): equal gender incidence.
Patients present with slow-growing, deep seated mass and compression symptoms related to anatomic location. Ill-defined borders and entraps surrouding tissues including fat and skeletal muscle. It is rubbery
Synovial sarcoma
What is the characteristic translocation?
Peak incidence?
Location of tumor
A malignant neoplasm of uncertain histotype with epithelial differentiation and characterized by a t(X:18) translocation.
It is also is cytokeratin positive
Account for 10% of adult soft tissue sarcomas.
Peak incidence in young adults (20-40 years).
The majority develop in the deep soft tissue:
- 60-70% arise in the lower extremity around the knee and thigh. Very rarely, intraarticular.
- Other locations include head & neck, pleura and viscera
Describe the gross morphology of synovial sarcoma
Histologically? Two types
Gross:
Usually sharply circumscribed and unencapsulated.
Yellow to gray-white cut surface.
Can have cyst formation.
Attached to tendons, tendon sheaths, joint capsules.
Calcification is common but rarely discernible
Histology:
1) Monophasic
- Short fascicles or whorls of ovoid spindle cells.
- Spindled cells are small, uniform with scant cytoplasm, dark nuclei, indistinct cell borders.
- Dilated, branching “hemangiopericytomatous” vascular pattern
- Mitotic activity moderate (<10 mitoses per 10 high-power fields)
2) Biphasic
- Spindled areas similar to monophasic synovial sarcoma.
- Plumper epithelioid cells with abundant pale cytoplasm, distinct cell borders form clefts, slits, tubular structures.
- Interface between patterns may be abrupt or more subtle.
3) Poory differentiated
- Sheets of large polygonal, anaplastic cells or round, primitive blue cells
- Abundant mitoses and necrosis
Calcification with or without ossification is common in all types
Chondroblastoma
Common location?
Symptoms on presentation?
Benign chondroid matrix producing tumor that commonly affects the epiphysis of long bones in adolescents and young adults with a slight male predominance (3:2).
<1% of bone tumors.
Most arise about the knee. Rarely flat bones (cranium, pelvis) are involved.
Patients present with several months to years history of pain involving a joint that may be accompanied by gait abnormality, swelling and decreased mobility.
It typically affectts the epiphysis of long bones.
Radiography: Lesions are usually well circumscribed, predominantly lytic, but with matrix calcifications
Gross: lesions are fleshy, whitish in its solid regions. A hemorrhagic cystic region can also be grossly evident. Secondary aneurysmal bone cyst frequently accompanies chondroblastoma
Histology:
Amphophilic or eosinophilic fibrochondroid matrix (no mature hyaline cartilage).
Irregularly distributed osteoclast-like giant cells.
KEY features on histology: Chicken-wire calcifications (consist of delicate powdery basophilic deposits that surround individual tumor cells or small clusters of cells. Also, Ovoid to round mononuclear cells with eccentric grooved nuclei and rare osteoclasts- like giant cells
