summary Melanomas are an aggressive skin malignancy of melanocytic origin. The condition is typically seen in patients between 50 and 70 years old who present with a pigmented skin lesion with a recent change in shape or size. Diagnosis is made with a biopsy showing melanocytes with marked cellular atypia with invasion into the dermis. Treatment is usually wide surgical excision. Epidemiology Demographics slightly more common in men (male:female ratio = 1.2:1) age bracket is 50-70yrs Anatomic location thumb > great toe > index finger sun exposed areas Risk factors sun exposure UV radiation suppresses skin immunity, induces melanocyte cell division, produces free radicals, damages melanocyte DNA family history skin characteristics blue eyes, fair hair and complexion, freckling xeroderma pigmentosa familial atypical mole or melanoma (FAMM) syndrome multiple benign and dysplastic nevi dysplastic nevi are a precursor immunesuppression Etiology Forms types include acral lentiginous melanoma subungual melanoma is a subtype of ALM Pathophysiology progresses through phases of growth Anatomy Melanocytes derived from neural crest cells found in deepest layer of epidermis, separated from dermis by basement membrane dermis is divided into papillary dermis and reticular dermis subcutaneous tissue is deep to reticular dermis Classification Breslow classification thickness =< 0.75mm thickness 0.76 - 1.5mm thickness 1.51 - 4mm thickness >4mm Clark classification Clark classification Level I Involves epidermis (in situ melanoma), no invasion Level II Invades papillary dermis Level III Invades papillary dermis up to papillary-reticular interface Level IV Invades reticular dermis Level V Invades subcutaneous tissue Presentation History pigmented lesion with recent change in shape or size nail trauma subungual melanoma renders the nail dystrophic and vulnerable to trauma Symptoms itching or bleeding Physical exam brown-black pigmented lesion, may ulcerate extension of brown-black pigment of the nail bed or nail plate to the cuticle and nail folds (Hutchinson sign) characterized by (ABCDEs) Asymmetry Border irregularity Color variation Diameter (<6mm benign) Elevation Enlargement Imaging CXR indications lungs are often first site of metastases Ultrasound indications diagnose lymph node involvement PET or CT indications detect metastases Studies Labs CBC AST and ALT liver metastases LDH predictive for poor prognosis Histology Melanocytes with marked cellular atypia invasion into the dermis vacuolated cytoplasm hyperchromatic nuclei with prominant nucleoli Differential Differentials for melanoma nevi seborrheic keratosis basal cell carcinoma Subungual melanoma is mistaken for trauma subungual hematoma onychomycosis Treatment Operative local resection with a 1cm margin indications lesion is < 1mm thick local resection with 1-2cm margin, sentinel node biopsy indications lesion is 1-2mm thick technique if sentinel node biopsy positive perform radical node dissection local resection, lymph node dissection, chemotherapy indications evidence of metastasis amputation indications subungual melanoma outcomes distal amputation with sufficient margins has similar recurrence rates and survival to proximal (carpometacarpal/tarsometacarpal) amputations may include lymph node dissection and isolated limb perfusion Prevention prevent melanoma with sunscreen and avoiding sun exposure Complications Recurrence usually regional lymph nodes Prognosis Depth is the most important prognostic factor < 0.7 mm - survival is 96% > 4.0 mm - survival is 47% Poor prognostic factors for melanoma deep lesion male sex lesion on neck or scalp positive lymph nodes and metastases ulceration Subungual melanoma has poor prognosis overall with 5yr survival 40-60%