KEY NOTES CHAPTER 2: SKIN AND SOFT TISSUE LESIONS - Soft Tissue Tumours. Flashcards

Question

What are the 2 main systems used to plan excision margins?

Answer 1

1. AJCC residual tumour classification | 2. Enneking classification

Answer 2

Typical behaviour of sarcoma: • Most have centrifugal growth pattern. • Compression of surrounding soft tissue produces 'pseudocapsule', a reactive zone around the tumour, harbouring nests of tumour cells. • Non-specialists may find sarcoma shells out easily, but this inevitably leaves viable tumour cells within pseudocapsule. • Sarcomas usually respect fascial boundaries until late in their progression.

Answer 3

- Describes tumour status following treatment. - Includes lymph nodes and sites of distant metastases. • R0 - no residual tumour • R1 - microscopic residual tumour • R2 - macroscopic residual tumour.

Answer 4

- Enneking classification correlates the tumour stage with the recommended excision margins depending on whether mass is benign or malignant. - Based on stage, the appropriate surgical margin is chosen to obtain local control.

Answer 5

1. Intralesional • 'Shell out' procedure. • Macroscopic tumour is left behind; recurrence ~ 100%. 2. Marginal • Pseudocapsule forms periphery of resection specimen. • Microscopic disease is left within reactive zone; recurrence is 40-60%. 3. Wide • Removes tumour and pseudocapsule with a margin of nonreactive normal tissue. • Risks leaving microscopic skip lesions; more likely with high-grade lesions. • Recurrence rates ~ 10%. 4. Radical • Removes all normal tissue of involved compartment. • Muscles are excised en bloc, from origin to insertion, including fascial sheaths. • In theory, leaves no residual disease; local recurrence rate 0.5%.

Answer 6

Chemosensitive tumours • Paediatric rhabdomyosarcoma, • Soft tissue Ewing's sarcoma • Synovial sarcoma Treatment ∘ Neoadjuvant chemotherapy ∘ Surgery,+/- radiotherapy ∘ Further adjuvant chemotherapy.

Answer 7

* Amputation considered when critical structures must be resected, which would otherwise leave a poorly functioning limb. * Limb salvage strategies have reduced amputation rates to ~ 5%. • To achieve low recurrence with limb salvage: 1. Neoadjuvant radiotherapy or, less commonly, chemotherapy 2. Resection: aim for wide margin while preserving critical neurovascular structures. 3. Reconstruction: functional recon with nerve grafts, nerve transfers, vascular reconstruction and free functioning muscle transfer. 4. Adjuvant radiotherapy or, less commonly, chemotherapy.

Answer 8

• Overall survival 50-60%. • Prognostic factors: age, metastasis at presentation, tumour size and depth. • Trojani histological grade is critical determinant of prognosis: 1. Low grade: 90% 5-year survival. 2&3. High grade: 50-60% 5-year survival M0;

Answer 9

* Children with metastatic disease, fare better than adults. * Radiotherapy has greater risk of long-term sequelae. * Chemotherapy may cause infertility.

Answer 10

• Controversial treatment for unresectable extremity sarcoma. Uses: • Neoadjuvant: reduce extent of extremity sarcoma to try to avoid amputation. • For extensive locoregional metastases.

Answer 11

* Primary tumours originate in skin; managed similar to other skin cancer; imaging rarely required if no evidence of metastasis. * Secondary tumours are skin metastases from cutaneous or noncutaneous sarcomas. 1. MFH 2. AFX 3. AS 4. DFSP

Answer 12

* Aka pleomorphic undifferentiated sarcoma. * Rare aggressive tumour; presents as a firm subcutaneous nodule in elderly. * Commonly affects thigh, upper limb and retroperitoneum. * 2∕3 located in skeletal muscle;

Answer 13

* Aggressive, multicentric tumour; typically on face and scalp of elderly. * At presentation, it usually extends beyond its clinical margins. * High rate of local recurrence and metastasis. * Surgical margins 5 cm, where possible.

Answer 14

* Aka pleomorphic undifferentiated sarcoma of skin. * Superficial cutaneous counterpart of MFH. * Presents as small, firm cutaneous nodules. * Usually on head and neck of elderly, in sun-damaged or irradiated skin. * Histology is indistinguishable from MFH - aggressive, poorly differentiated lesion. * Prognosis usually excellent (unlike MFH). * AFX rarely recurs WLE & clear margins.

Answer 15

* A tumour of intermediate malignancy (prone to local recurrence but rarely metastasises). * Slow-growing, red-brown nodule, most common on the trunk. * Mean age ~ 35 years. * Pathogenesis involves a distinctive rearrangement of chromosomes 17 and 22. * Excised with wide margin (>2-3 cm) down to deep fascia: local recurrence rates ~ 15%. * Mohs LRR ~ 1.3%. * Imatinib (tyrosine kinase inhibitor): neoadjuvant treatment for inoperable, metastatic or recurrent DFSP.

Answer 16

~500 yr in UK

Answer 17

∘ Osteosarcoma ∘ Ewing's sarcoma ∘ Chondrosarcoma.

Answer 18

• Investigated and managed in specialist bone sarcoma centres. Treatment: 1. Neoadjuvant therapy (chemotherapy±radiotherapy) 2. Surgical resection and reconstruction 3. Postoperative adjuvant therapy, determined by surgical margins and histology.

Answer 19

Reconstruction of long bones: ∘ Bespoke prostheses ∘ Allograft bone ∘ Extracorporeal radiotherapy. - Involved bone is resected. - Tumour is excised from bone after removal from patient. - Remaining bone is irradiated to 90 cGy (which avoids collateral soft tissue damage) and reinserted as graft. Capanna technique: • Augmenting vascularity with free vascularised bone from fibula, inserted into diaphysis of irradiated long bone after reaming.

Answer 20

(1) to aid in planning the course of treatment, (2) to provide insight into the prognosis, (3) to assist in evaluating the results of treatment, (4) to facilitate effective interinstitutional communication, and (5) to contribute to continuing investigation of human malignancies.

KEY NOTES CHAPTER 2: SKIN AND SOFT TISSUE LESIONS - Soft Tissue Tumours. Flashcards

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