- Melanoma: thickness is most important prognostic indicator (except acral lentiginous –> stage)
- CMN – giant is one that would be larger than 20cm in an adult (9cm in HN and 6 on trunk)
- <10% of malignant transformation
- Have greater rates of CNS malignancies in leptomeninges, also increase of rhabdomyosarcoma and spina bifida
- Risk for limb underdevelopment
- Risks for CNS involvement include multiple nevi, posterior midline, satellite; if neurologic symptoms are present- hydrocephalus, seizures paresis etc prognosis is grave
- Xeroderma pigmentosum associated
- Subtypes:
- Melanoma in situ:
- Wide local excision (even on digits!)
- Lentigo maligna melanoma (5-10%), Hutchinson’s freckle
- Low malignant potential
- Pre-cancerous= 1 cm margins
- Superficial spreading (60-70%)
- Lateral spreading in epidermis
- Nodular (15-20%): occur in sun exposed skin and often arise from pre-existing nevi
- Trunk/head/neck
- Increased incidence in men
- Rapid vertical growth phase
- Increased metastatic potential
- Dark/dome shaped, look like a blood blister
- Acral lentinginous melanoma (2-5%)
- Occurs in dark skinned patients
- Palms/nail bed/ soles of feet. Aggressive
- Worse prognosis than other melanoma subtypes
- Treatment is usually amputation at the next proximal joint
- SubUngual
- Risk factors for subungual melanoma: age >50, width greater than 3mm, change in color over time, pigmentation of periungual skin
- Melanoma in situ of thumb can just undergo WLE
- Subungual melanoma: localized should undergo amputation just proximal to distal joint to clear disease while maintaining length, SLNB
- Shave biopsy first after 4-6 weeks without change –> melanocytic hyperplasia can be observe, atypia must be excised
- If index finger DIP amputation (level of joint just proximal to lesion)
- Ablation of nail bed and resurfacing for melanoma in situ or melanotic dysplasia (WLE and skin grafting)
- Benign juvenile melanoma: (spitz nevus, spindle cell nevus, epitheloid nevus), pink/red and appears on face, shows giant spindle cells, complete excision recommended
- Breslow grading system:
- 1: 0-0.75mm
- 2: 0.76-1.5mm
- 3: 1.51-4mm
- 4: >4mm
- If excision upgrades breslow no need to re-excise especially If < 2mm
- Clark Grading System:
- 1: epidermis
- 2: invading papillary dermis
- 3: at junction of papillary dermis and reticular dermis
- 4: invading reticular dermis
- 5: involving subq fat
- SLNB is indicated in melanomas >0.8mm thickness and if there is ulceration àDecreases mortaity
- SNLB for intermediate thickness 0.8-4mm
- Satellite lesion makes t4
- Immunohistochemical markers: s-100, HMB-45, MART-1
- If patient has visceral mets (other than lung)à bad prognosis
- Elevated LDHà also bad prognosis
- Management:
- Margin recommendations-
- 1-4mm: intermediate thickness and need SLNB
- Preparotid region requires superficial parotidectomy
- Lentigo maligna *aka hutchinsons freckle*
- 1cm margins
- Hutchinson’s freckle: lentigo maligna- melanoma in situ, found only in layers of epidermis, found in fair skinned elderly persons 1cm margin –> await final results prior to reconstruction to see need for SLNB etc
- >4mm WLE with 2cm margin no SLNB (does not confer survivability)
- Miscellaneous:
- For pregnant patients, resection should be completed with local if within 1st trimester
- 2nd trimester may undergo general anesthesia for SLNB
- Tissue expansion may be used to cover 50% of scalp
