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Soft tissue and neural tumour cases

Soft tissue tumour, nerve tumour and skin lesion cases including liposarcoma and melanoma.

37 questions 6 source pages

Images appear with the first question taken from each source page — tap a question to open it.

Q1Describe the clinical photo and how you assess the mass.▸

Large swelling over the left back with some overlying skin bruises
Assess for inflammation, nature of mass (consistency), position and attachment, regional lymph nodes
Large soft intramuscular swelling

Q2What features suggest malignancy in a soft tissue tumour?▸

>5cm, deep to fascia
Progressive in size, onset of pain

Q3How are soft tissue sarcomas classified and staged?▸

AJCC: 1. size (>5cm), 2. deep to fascia, 3. node, 4. metastasis, 5. grade
Stage 1 = low grade, 2 = high grade, 3 = deep to fascia, 4 = metastasis
Grading: low (well differentiated), intermediate (myxoid), high (de-differentiated)
Stage 1-2: 80% 5-year survival; stage 3-4: 50% 5-year survival

Q4How would you investigate a suspected soft tissue sarcoma?▸

X-ray to see bony destruction
MRI: extent, invasion, NV involvement (increase T2, decrease T1; gadolinium - increased T1 peripherally, decreased centrally in cystic/necrotic areas)
Bloods to rule out infection and check INR
Image-guided biopsy (histology + MDM2 genetic marker)
At least CT thorax to rule out metastasis

Q5What is the management and when is pre-operative radiotherapy given?▸

Wide local excision +/- radiotherapy
May consider marginal excision in low grade (well-differentiated liposarcoma)
Pre-op RT depends on histological grade, cell type (myxoid), and proximity to NV bundle
Myxoid type: CT TAP for abnormal sites of metastasis; preop radiotherapy as vascular

Q6What are the features of MFH, synovial sarcoma and liposarcoma?▸

MFH (= undifferentiated pleomorphic sarcoma): most common soft tissue sarcoma; slow growing, no ecchymosis, lung mets; iso T1, increased T2; pleomorphic (>80%) > giant cell (10%) >infl (<10%), most high grade
Synovial sarcoma: not synovial origin; commonest sarcoma in young adults (15-40) in the foot; LN and lung mets; calcification 25%; gene (X;18); biphasic epithelial + spindle cells; always high grade
Liposarcoma: 2nd most common soft tissue sarcoma, not from lipoma; lipoblasts; types well differentiated/sclerosing/myxoid; high grade round cell/pleomorphic/dedifferentiated

Q7What is a neurilemmoma and what are its histological features?▸

Benign schwannoma
Antoni A: spindle cells in intersecting bundles (battle formation); Antoni B: less cellular, loosely arranged cells
Verocay bodies: pathognomonic - two rows of aligned nuclei in palisading formation
S100 positive; MRI string sign; paraesthesia in distribution of the peripheral nerve

Q8What is the treatment of neurilemmoma?▸

Observe
Excision carries a high rate of sensory deficit
Careful dissection, excise lesion parallel to nerve fascicles

Q9How do neurofibroma and schwannoma differ in relation to nerve fibres?▸

Schwannoma is eccentric to nerve fibres
Solitary neurofibroma is central to nerve fibres
Neurofibroma involves non-myelinating Schwann cells and other perineural cells
Excision with nerve graft if symptomatic

Q10Compare NF type I and type II.▸

Type I (von Recklinghausen): chromosome 17, tibia pseudoarthrosis, spine most common skeletal involvement - dystrophic scoliosis and dural ectasia
Type II: chromosome 22, bilateral vestibular schwannoma, central meningioma, no scoliosis
Autosomal dominant disorder of neural crest
Skeletal: scoliosis, kyphosis, atlantoaxial instability; congenital anterolateral bowing of tibia/forearm; hemi-hypertrophy

Q11Compare dermal and plexiform neurofibromas.▸

Dermal: single peripheral nerve, fusiform swelling; 90% sporadic, 10% in NF1; at puberty; do not become malignant
Plexiform: multiple nerve bundles, bag of worms; pathognomonic of NF1; early childhood; 10% become malignant (MPNST)

Q12What is MPNST and neuroblastoma?▸

MPNST (malignant schwannoma): arises from large nerves (sciatic, brachial plexus), motor and sensory deficit; treat with wide surgical resection + radiotherapy
Neuroblastoma: malignant from sympathetic neural tissue; most common solid tumour of childhood
Adrenal involvement causes tachycardia and abdominal mass; bone mets common and poor prognostic; lecturer describes overall good prognosis
Treatment: chemo + stem cell transplant + surgical excision

Q13What are the types of Schwann cells and their significance?▸

Myelinating Schwann cells - found in large nerves
Non-myelinating Schwann cells - found in small nerves, responsible for neurofibromatosis

Q14What is an intramuscular myxoma?▸

Benign, homogeneous
Excise if symptomatic
MRI: bright T2, dark T1

Q15What is rhabdomyosarcoma?▸

Malignant; most common soft tissue sarcoma in children
Rapidly growing painless mass
Treatment: chemo for metastasis, radiotherapy for inoperable, excision

Q16What is leiomyosarcoma?▸

Aggressive malignant tumour from smooth muscle cells lining small blood vessels
Osteolytic, moth-eaten lesions in the metaphysis of long bones
Treatment: chemotherapy + wide surgical resection

Q17What is dermatofibrosarcoma protuberans?▸

Fibrogenic cutaneous sarcoma
Can result from neurofibromatosis
t(17;22) encodes PDGFB/COL1A1 fusion protein

Q18What is malignant fibrous histiocytoma (undifferentiated pleomorphic sarcoma)?▸

Most common soft tissue sarcoma in adults
Pain and swelling; high grade - looks like osteosarcoma
Types: pleomorphic 80-85%, giant cell 10%, inflammatory <10%
Treatment: same as osteosarcoma - wide local resection and radiation

Q19What is extra-abdominal desmoid tumour and its associations?▸

Aggressive fibromatosis; most invasive of benign soft tissue tumours
Associations: Dupuytren's disease, Ledderhose disease, FAP
Distinctive rock hard mass; oestrogen receptor positive
Treatment: tamoxifen (oestrogen receptor blocker) and radiotherapy

Q20What is nodular fasciitis?▸

A reactive lesion

Q21What is plantar fibromatosis (Ledderhose disease)?▸

Myofibroblast and collagen proliferation
Similar process to Dupuytren's fibromatosis
Ask about hand involvement and Peyronie's disease in men

Q22What is calcifying aponeurotic fibroma?▸

Painless mass in the hands and feet of children and young adults

Q23What is a glomus tumour and where does it occur?▸

Benign subungual tumour arising from the glomus body, a perivascular temperature-regulating structure
Frequently at the tip of a digit or beneath the nail
Usually young adults 20-40 years; 3/4 in hand, 1/2 in finger, 1/2 with distal phalanx erosion
Ddx: melanoma

Q24What is the classic clinical triad of a glomus tumour?▸

Paroxysmal pain
Exquisite tenderness to touch
Cold intolerance

Q25What are the Love and Hildreth tests?▸

Love test: pinhead -> pain
Hildreth test: tourniquet -> less pain

Q26What imaging and treatment are used for a glomus tumour?▸

X-ray: pressure erosion; MRI: low T1, high T2
Marginal excision +/- reconstruct nailbed contour with autogenous fat graft
Recurrence 20%

Q27Describe the clinical findings in this patient with a glomus tumour.▸

Partial bluish discoloration of the nail
No nail ridging
Ddx: melanoma
Also known as paraganglioma

Q28What is Hutchinson sign and what does it imply in this patient?▸

Subungual discolouration extending to involve the eponychium
Hutchinson sign - treat as melanoma until proven otherwise

Q29What are the classical ABCDE features of melanoma?▸

Asymmetry
Border
Color
Diameter (<6mm likely benign)
Elevation/enlargement

Q30What are the risk factors for melanoma?▸

Fair skin, multiple nevi, family history
Sun exposure, immunosuppression

Q31How is melanoma worked up?▸

Hx: recent change, itch, bleeding
PE: ulceration, satellite lesions, regional lymph nodes
Imaging: CT thorax and abdomen to rule out metastasis (lung/liver); USG for lymph nodes
Dx: incisional biopsy, LN biopsy

Q32What are the Breslow and Clark classifications of melanoma?▸

Breslow: depth in mm - <0.75 / 1.5 / 4 / >4; survival 96% if <0.7mm, 47% if >4mm
Clark I: epidermis (in situ), no invasion (normal melanocytes at deepest epidermal layer)
Clark II: papillary dermis; III: papillary dermis up to papillary-reticular interface
Clark IV: reticular dermis; V: subcutaneous tissue

Q33What determines the treatment of melanoma?▸

Depends on grading, lymph nodes, metastasis, location of lesion
1mm -> 1cm resection margin
>1mm -> 2cm margin + sentinel LN biopsy (+/- radical LN dissection)
Subungual melanoma -> distal amputation + sentinel LN biopsy
Positive LN/metastasis: local resection, LN dissection, chemotherapy
Poor prognostic factors: depth, male, neck/scalp site, ulceration, LN or metastasis

Q34What is a schwannoma (neurilemma)?▸

Encapsulated tumour on the surface of a peripheral nerve
Associated with mutation affecting the NF2 gene

Q35What are the clinical and MRI findings in a schwannoma?▸

Hx: paraesthesia in the distribution of the peripheral nerve
PE: positive Tinel sign
MRI: T1 low, T2 high, enhances with contrast; string sign (Ddx: neurofibroma)

Q36What is the histology of a schwannoma?▸

Antoni A: spindle cells arranged in intersecting bundles
Antoni B: loosely arranged cells
Verocay bodies are pathognomonic
Uniform S100 antibody staining

Q37What is the treatment of a schwannoma?▸

Marginal excision with careful dissection
Excise the mass parallel to the nerve

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Soft tissue and neural tumour cases