Langerhans cells:

  • Antigen recognition
  • Involved in contact hypersensitivity

Merkel cells:

  • Sensory mechanoreceptors.
  • Merkel cell carcinoma presents as red/purple papulo-nodule.
  • A neuroendocrine tumor with staining for neuron specific enolase and neurofilament protein.

Glomus cell tumor:

  • Benign
  • Painful, subungal tumor
  • From glomic end organ
  • Tx: shell out


  • Involves apocrine glands, therefore see after puberty in axilla, groin

Basal cell CA: 4:1 more common than SCC

  • BCC has peripheral palisading of nuclei on pathology.
  • Glistening and Pearly appearance.

FTSG: contracts less than STSG

STSG: Donor site regenerates from hair follicles, skin appendages.

  • STSG blood supply by imbibition 1st few days, then neovascularization days 2-7 (capillary ingrowth)

Flap necrosis: most commonly due to venous thrombosis

Melanoma 4 types:

  • Nodular (worst, early mets)
  • Superficial spreading
  • Lentigo maligna
  • Acral lentiginous

Risks for melanoma:

  • Dysplastic nevi
  • Congenital nevi
  • BK
  • Mole syndrome (100% risk)

Melanoma sites:

  • Skin > eyes > rectum
  • #1 skin site for men is back, in women is legs

Worse Px if on BANS: back, arms, neck, scalp

Melanoma excision Margins:

  • Depth <1mm: 1 cm
  • Depth 1-4mm: 2 cm
  • Depth >4mm: 3 cm


  • <0.75mm (90%cure)
  • 0.75 to 1.65mm
  • 1.65-4mm
  • >4mm (80% distant metastasis)


  • Extends beyond wound margins
  • Failure of collage breakdown and increase collagen production.

Hypertrophic scar: Does not extend beyond margins.

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