Msck soft tissue tumours Flashcards
Epi of Rahbdomyosarcoma
Most common soft tissue Sarcoma
of children
Varients of Rhamdomyosarcoma
1) Pleomorphic Rhabdomyosarcoma
2) Embryonal Rhabdomyosarcoma
3) Alveolar Rhabdomyosarcoma
Microscopic featurs:
* Typical rhabdo-myoblasts with eccentric eosinophilic cytoplasm
* high cellularity
* “Cambium layer” of tightly packed tumour cells beneath the epithelium
features of?
Embryonal Rhabdomyosarcoma (of the SM)
Embryonal Rhabdomyosarcoma
Microscopic featurs:
* Typical rhabdo-myoblasts with eccentric eosinophilic cytoplasm
* high cellularity
* “————–” of tightly packed tumour cells beneath the epithelium
* eccentric : deviating away from the center
Microscopic featurs:
* Typical rhabdo-myoblasts with eccentric eosinophilic cytoplasm
* high cellularity
* “Cambium layer” of tightly packed tumour cells beneath the epithelium
Microscopic features:
* Tumour cells line hollow spaces
* Fibro-vascular septa
* “Picket fence”-like arrangement
features of?
Alveolar Rhabdomyosarcoma
Alveolar Rhabdomyosarcoma
Microscopic features:
* Tumour cells line hollow spaces
* Fibro-vascular septa
* “————–”-like arrangement
Microscopic features:
* Tumour cells line hollow spaces
* Fibro-vascular septa
* “Picket fence”-like arrangement
Genetic confirmation of Synovial Sarcoma?
X;18 chromosomal translocation
(important for confirmation of the diagnosis but not specific for Synovial Sarcoma)
location of Synovial Sarcoma
▪ Lower extremities (most common)
▪ Tissue adjacent to a joint, rather than in a joint cavity
Synovial Sarcoma
Microscopic features:
▪ Either biphasic growth pattern; ——— and ——- cells
▪ Or monophasic pattern; only ——— cells component present
▪ Either biphasic growth pattern; both epithelial and spindled cells
▪ Or monophasic pattern; only the spindled component present
Microscopic features
▪ Either biphasic growth pattern; both epithelial and spindled cells
▪ Or monophasic pattern; only the spindled component present
features of?
Synovial sarcoma
Benign Fibrous Histocytoma is aka?
Dermatofibroma
Macroscopic Features:
- Circumscribed, small (<1cm) mobile nodules, in the dermis or subcutaneous tissue
Microscopic Findings:
- Bland, spindle cells admixed with histiocyte-like cells
features of?
Dermatofibroma
(Benign Fibrous Histocytoma)
Benign Fibrous Histiocytoma (Dermatofibroma)
Macroscopic Features:
- Circumscribed, small (<1cm) mobile nodules, in the dermis or subcutaneous tissue
Microscopic Findings:
- Bland, spindle cells admixed with ———-cells
Macroscopic Features:
- Circumscribed, small (<1cm) mobile nodules, in the dermis or subcutaneous tissue
Microscopic Findings:
- Bland, spindle cells admixed with histiocyte-like cells
location of Undiffrentiated Pleomorphic sarcoma
Musculature of the proximal extremities or retroperitoneum
Macroscopic Features:
▪ Large tumours (5-20cm)
▪ Gray-white, un-encapsulated lesions
Microscopic Findings:
▪ Storiform architecture (spiral appearance)
▪ Prominent cytologic pleomorphism
▪ Presence of bizarre multinucleate cells
features of?
Undifferentiated Pleomorphic Sarcoma
Epi of Fibrosarcoma
Most common in adults
Loc of Fibrosarcoma
Deep tissues of the thigh, knee and retro-peritoneum
Macroscopic Features:
▪ Soft, un-encapsulated, infiltrative mass
▪ Cut-surface: Areas of haemorrhage and necrosis
Microscopic Findings:
▪ Spindle cells growing in a herring-bone fashion
▪ Possible presence of myxoid stroma
▪ High mitotic index and necroses
features of?
Fibrosarcoma
Progression of Fibrosarcoma
▪ Slow growth (over several years)
▪ Local recurrence (>50% of cases)
▪ Haematogenous dissemination (>25% of cases), usually to the lungs
——: Benign tumour of mature adipose tissue
Lipoma
epi of Lipoma
Most common soft tissue tumour in adults
Macroscopic Features:
- Soft, yellow, well encapsulated (demarcated) mass
Microscopic Findings:
- Mature, Uniform white fat cells (Uniform adipocytes)
- Thin collagenous pseudo-capsul
- No pleomorphism
features of?
Lipoma
CM of Lipoma
- Mobile, slowly enlarging, painless mass
- Angiolipomas can manifest with local pain
location of Liposarcoma
Deep soft tissues or retro-peritoneum
Genetic predispostion
Well-differentiated Liposarcomas –> Amplification of a region of —– (containing the ——— gene)
Well-differentiated Liposarcomas –> Amplification of a region of 12q (containing the -MDM2 gene)
Genetic Predisposition
Myxoid/Round Cell Liposarcomas –> t(–;–)
chromosomal translocation
Myxoid/Round Cell Liposarcomas –> t(12;16) chromosomal translocation
Macroscopic Features:
- Relatively well-circumscribed lesion
Microscopic Findings:
- Significant variation in adipocyte siz
- Presence of lipoblasts, with cytoplasmic lipid vacuoles that scallop the nucleus and appearance similar to fetal fat cells
- Focal nuclear Atypia
featrues of?
Liposarcoma
The 2 varients of Liposarcoma
▪ Low-Grade variant –> Well-differentiated Liposarcoma
▪ High-Grade variant –> Myxoid/Round Cell Liposarcoma
Macroscopic features:
- Prominent high water myxoid component
- Small lipomatous component
- Gelatinous yellowish appearance with red-tinged foci
Microscopic features:
- Low cellularity
- Uniform oval tumour cells
- Prominent, branching capillary pattern
- Variable numbers of non-atypical adipocytes
features of?
Myxoid Liposarcoma
