Skin & soft tissue Flashcards
Melanoma TNM
T:
- Breslow depth
- Presence of ulceration
N:
- Number of LN
- Mode of detection (sentinel node -micro, clinical - macro)
- Intransit/satellite lesions
M:
Site of metastasis, LDH level
Stage:
- T1-T2a
- t2b-t4
- N+ (note 4 subgroups A-D)
- M+
MSLT-1
Randomised to WLE +/- SLNBx
In SLNBx group
- If positive then immediate complete lymphadenectomy
- If negative then nodal observation and salvage lymphadectomy
In WLE alone group
- Nodal observation and salvage lymphadenectomy
Intermediate thickness melanomas (MSLT-1)
- Of all comers over time 1:5 (20%) will have or develop nodal disease
- 15% of SLNBx patients will be positive – 80% would have no residual disease on CLNDx
- 95% of negative SLNBx will not develop nodal disease by 10 years
- If negative SLNBx 1:20 (5%) chance of developing nodal disease (false-negative)
- Overall, no difference in survival @ 10 years, but worse survival if node positive disease without SLNBx (1:5 chance of being in this group if SLNBx not done HR 0.56 of death – proportion alive at 10yrs = 62 vs 41%)
So; do SLNBx because better melanoma specific survival for those that have positive nodes
Care pathway for melanoma 2021
Layers of skin
But mate, Britney Spears Grows Like Cancer
Subcutaneous fatty tissue
Dermis
- Reticular
- Papillary
Epidermis
- Basement membrane
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
What layer do melanocytes and merkel cells live?
Melanoma stratum basale epidermis (if in the dermis then a melanoma)
Merkel cells also stratum basale
Fitzpatrick skin types
1-6
Lowest are whitest
Easy to burn
Never tan
Red hair
Blue eyes
Subtypes of melanoma
- Lentigo maligna
- Superficial spreading
- Nodular
- Acral including subungal
- Desmoplastic
Stains suggestive of melanoma
- S100
- SOX10
- MelanA
- HMB45
- (BRAF PCR)
MSLT2
- MSLT2 trial showed no survival benefit from immediate CLNDx for positive SLNBx, also lymphoedema rate of 25 vs 5%
Tumour marker used in melanoma
LDH
Clinical appearance of Merkel Cell?
AEIOU Asymptomatic Expanding Immunosuppressed Older UV rays
What causes Merkel cell carcinoma
UV rays Merkel cell polyomavirus Age and immunosuppression
High risk features SCC
- Large >2cm
- >4mm thick
- Poorly differentiated
- Near major nerves of head or neck
- Infiltrative growth
- Extracutaneous growth
- Immunosuppressed
- Histology
- Perineual
- Lymphovascular invasion
- Desmoplasia
- Clinical features
- Rapid growth
- Ears/lips/hands/feet/pretibial/anogenital
- Multiple cancers
- Immunosuppression
- Clinical features
What is innervated by the median nerve?
Motor:
- All the muscles of the FLEXOR forearm except (FCU, ulnar half of FDP)
- The LOAF (lumbricals 1-2, oppenens pollicis, abductor policis brevis, flexor pollicis brevis) of the hand
Sensory:
- The radial half of the palm and palmar surface of radial digits 1-3.5
- Extensor surface of radial digits 1-3/5 from the PIPJ distally
- The palm is innervated by the palmar branch of median which doesn’t pass through the carpal tunnel
Describe the course of the median nerve and where it can be compressed
- Medial and lateral cords embrace the brachial artery in proximal arm
- Overlies the artery, runs deep to biceps and superficial to brachialis in medial arm
- Lies medial to artery in the cubital fossa
- Enters the forearm between the head of pronator teres*
- Passes deep to the fibrous arch* of FDS, runs between FDS and FDP
- Emerges at the wrist, to the radial side of the FDS tendons, its crossed by PL and FCR tendons
- Passes through the carpal tunnel* to reach the hand
Branches
- Anterior interosseous branch
- Palmar cutaneous branch
- Recurrent motor branch to the thenar muscles
Describe the course of the ulna nerve
Arises from C7-C8-T1 as continuation of the medial cord
Runs medial to the brachial artery
Mid humerus it pierces the intermuscular septum to enter the extensor/posterior compartment
Passes posterolateral behind the medial epicondyle (where it is palpable) through the ulnar tunnel (between medial epicondyle and the olecranon)
Pierces between the two heads of the FCU to travel deep alongside the bone
At the wrist, the ulnar nerve travels superficially to the flexor retinaculum, and is medial to the ulnar artery. It enters the hand via the ulnar canal (Guyon’s canal). In the hand, the nerve terminates by giving rise to superficial and deep branches.
What is supplied by the ulna nerve
Sensory:
- Ulna half of the hand (including digits 4-5)
Motor:
- Anterior forearm FCU and ulna half of FDS
- Hand muscles except palmaris brevis and LOAF
What is Guyons canal
Guyon’s canal
- Fibro-osseous tunnel located at the level of the palm, transmits the ulnar neuromuscular bundle from the forearm into the hand
- Borders
- Floor: Transverse carpal ligament, pisohamate ligament, hypothenar muscles
- Roof: Palmar fascia and the palmaris brevis muscle
- Lateral: hook of hamete
- Medial: pisiform
- Contents
- Ulnar nerve; bifurcating into deep motor and superficial sensory branches
- Ulnar artery
- Venae comitantes of the ulnar artery
- Lymphatics
Peripheral nerve injury pathophysiology
- Degree of injury:
- Neuropraxia:
- Myelin injured, causes conduction block.
- Heals fast, full recovery (eg. Saturday night radial palsy)
- Axonotmesis:
- Axon injured, a portion remains proximally attached to the cell body, distal portion undergoes “Wallerian degeneration”.
- Proximal portion will attempt to grow at 1mm/day.
- Recovery achievable if supporting tissues (endo, peri, epineurium) intact and <18-24/12 (after which neuromuscular junction irreversibly damaged).
- Neurotmesis:
- Myelin, axon and supporting structures injured.
- No recovery, need surgery.
- Neuropraxia:
- Management:
- Observation
- Surgery:
- Neurolysis
- Direct repair
- Nerve graft
- Nerve transfer
- Timing of surgery:
- Early (3 days): lacerations; neurotmesis
- Subacute (3 weeks): blunt / ragged transections; neurotmesis
- Delayed (3 months): lesions-in-continuity; axonotmesis
- Late (>1y): salvage procedures
explain ulnar paradox
The ulnar paradox describes the counter-intuitive situation of a distal ulnar lesion causing a worse claw-hand deformity. If the ulnar nerve lesion occurs more proximally (closer to the elbow), the flexor digitorum profundus muscle may also be denervated. As a result, flexion of the IP joints is weakened, which reduces the claw-like appearance of the hand. With more distal lesions, the FDP maintains the flexion of the IP joints and the affected lumbricals cannot oppose the flexion. (JB)
What cancers are common in Li fraumeni?
SLAB
Sarcoma
Leukaemia
Adrenal adrenocortical carcinoma
Breast/Brain
What cancers are common in NF1?
- Neurofibromas – cutaneous, plexiform, nodular
- Optic pathway gliomas and CNS tumours – astrocytomas, brainstem gliomas
- Soft tissue sarcomas
- Malignant peripheral nerve sheath tumours
- Arise from pre-existing neurofibromas that have under gone malignant transformation
- 5-13% lifetime risk
- Rhabdomyosarcomas
- Early age, GU site
-
GIST
- Usually small bowel (70%), often multiple
- Glomus tumours
- Malignant peripheral nerve sheath tumours
- Other tumours
- Juvenile myelomonocytic leukaemia of childhood
- Phaeochromocytoma
What cancers are common in NF1?
- Neurofibromas – cutaneous, plexiform, nodular
- Optic pathway gliomas and CNS tumours – astrocytomas, brainstem gliomas
- Soft tissue sarcomas
- Malignant peripheral nerve sheath tumours
- Arise from pre-existing neurofibromas that have under gone malignant transformation
- 5-13% lifetime risk
- Rhabdomyosarcomas
- Early age, GU site
-
GIST
- Usually small bowel (70%), often multiple
- Glomus tumours
- Malignant peripheral nerve sheath tumours
- Other tumours
- Juvenile myelomonocytic leukaemia of childhood
- Phaeochromocytoma
Sarcoma grading and staging
- Grading
- Classified as low (grade I), intermediate (grade II) or high (grade III)
- Depends on
- Differentiation
- Necrosis
- Mitotic count
- Staging
- Size – T1_<_5, T2 >5
- Depth related to fascia – superficial T1a or 2a, deep T1b or 2b
- Nodal spread is rare
Synoptic report melanoma
