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Pathology-Soft Tissue Tumours
I. Benign Tumours:
|
Tumour Type |
Presentation |
Histology |
Key Features |
|---|---|---|---|
|
Lipoma |
Painless subcutaneous mass (limbs, trunk), adults. |
Lobules of mature adipocytes. |
Most common soft tissue tumour. |
|
Angiolipoma |
Painful, often multiple subcutaneous masses, adults. Upper limb (forearm) common. |
Mature adipocytes & capillary-like vessels with fibrin microthrombi. |
Pain is a key differentiator. |
|
Spindle Cell Lipoma |
Painless subcutaneous mass (upper back, shoulders, neck), adults. Male predilection. |
Mature adipocytes, spindle cells, fibromyxoid stroma with thick collagen. |
Location and patient demographics are important. |
|
Angioleiomyoma |
Painful subcutaneous mass, lower limbs. More common in women. |
Mature smooth muscle cells around thick-walled blood vessels. |
Pain and location are key. |
|
Giant Cell Tumour of Tendon Sheath |
Painless, slow-growing nodule (finger, toe). Peak age 20-40, female preponderance. |
Round mononuclear cells, osteoclast-like multinucleated cells, macrophages, haemosiderin. |
Location and cell types are characteristic. |
|
Fibroma of Tendon Sheath |
Firm nodule attached to tendon (finger). Young/middle-aged adults, male preponderance. |
Bland fibroblasts, thin slit-like vessels in fibrous stroma. |
Location and cellular composition are diagnostic. |
II. Fibromatoses (Locally Aggressive, Non-Metastasizing):
- Superficial: Dupuytren's contracture (palms), Ledderhose's disease (soles).
- Deep (Desmoid fibromatosis): Limb girdles, abdominal wall, mesentery.
- Histology: Bland spindled fibroblasts in broad fascicles, infiltrating surrounding structures. Significant local recurrence risk near vital structures.
III. Solitary Fibrous Tumour:
- Slowly enlarging deep soft tissue mass in adults.
- Histology: Haphazardly arranged bland fibroblastic cells, varying cellularity and collagenization, dilated branching blood vessels.
- Mostly benign, but a small percentage can exhibit malignant behaviour.
IV. Malignant Tumours (Sarcomas):
|
Tumour Type |
Presentation |
Histology |
Key Features |
|---|---|---|---|
|
Liposarcoma |
Most common soft tissue sarcoma. Adult, deep-seated mass (extremity, limb girdle, retroperitoneum). |
Well-differentiated: Mature adipocytes with variation in cell size, bizarre hyperchromatic stromal cells. Common local recurrence, no metastasis. |
Deep location and histologic subtype are crucial. |
|
Leiomyosarcoma |
Enlarging mass (retroperitoneum or limbs), adults. |
Fascicles of atypical smooth muscle cells. |
50% metastasize. |
|
Rhabdomyosarcoma |
Embryonal: Young children (head/neck, genitourinary). |
Skeletal muscle differentiation. |
Age and location strongly indicate subtype. |
|
Synovial Sarcoma |
Young adults, longstanding pain, deep soft tissue mass. |
Highly cellular spindle cells, epithelioid cells. t(X;18) translocation. |
Aggressive, poor long-term survival. |
|
Pleomorphic Undifferentiated Sarcoma |
High-grade, large, deep-seated, aggressive. No specific differentiation identified. |
No specific differentiation. |
Aggressive behavior and lack of identifiable differentiation are defining features. |
