Malignant<unk>  is the most common fatal skin cancer that arises from the epidermal melanocytes, which are neural crest cells involved in the synthesis of melanin (a brown pigment with photoprotective properties). The prevalence of<unk>  is approximately 150 - 200 per 100,000 individuals. It may be caused by sporadic genetic mutations (e.g. BRAF and/or N-RAS) or may be part of familial syndromes (e.g. familial atypical multiple mole<unk>  syndrome).<unk>  may be classified into either cutaneous or non-cutaneous<unk> s. The most common 4 subtypes of cutaneous<unk>  include superficial spreading<unk> , nodular<unk> , acral lentiginous<unk> , and lentigo maligna<unk> . Development of<unk>  is the result of multiple genetic mutations (multiple hits). The progression to<unk>  usually involves the serine-threonine kinases of the MAPK/ERK pathway (mitogen-activated protein kinase) following mutation of either the N-RAS or BRAF oncogene. On gross pathology, the majority of<unk> s appear as hyperkeratotic, black-brown, asymmetric nodules with irregular borders, but the morphology of the lesion mostly depends on the subtype of<unk>  and amelanotic (no pigmentation)<unk> s are not uncommon. On microscopic histopathological analysis, each subtype of<unk>  has unique characteristic features. The two most potent risk factors in the development of<unk>  are light-colored skin and exposure to ultraviolet radiation. If left untreated,<unk>  progression occurs both horizontally (radial growth plate) and vertically (vertical growth plate) and is then followed by dermal invasion and distant metastasis. Common sites of metastasis include bones, brain, kidneys, lungs, liver, and skin (distant site). The 5-year relative survival of patients with<unk>  is highly dependent on the stage at diagnosis. Staging is based on the 2010 AJCC TNM Classification and is divided into stage 0 or<unk>  in situ, stage I or invasive<unk>  with good prognosis, stage II or high-risk<unk> , stage III or<unk>  with regional lymph node metastasis, and stage IV or<unk>  with distant metastasis. The predominant treatment for primary<unk>  is wide excision of the lesion margins. The choice of clinical margins is based on the tumor thickness. When lymph nodes are involved, complete dissection of the nodal basin is recommended. Chemotherapy is indicated for high risk<unk> s (stages IIB-IV) as adjuvant therapy and for metastatic disease as first-line therapy. Once diagnosed, follow-up at regular intervals is recommended.
Melanoma
Xanthoma
Angiosarcoma
Basal cell carcinoma
Angiokeratoma
Nevus
Sarcoma
Soft tissue sarcoma