Editing Non-melanoma skin cancer (section)

== '''BCC''' ==

** Risk factors

*** Exposure to sunlight - intense intermittent exposure to UV radiation
*** Susceptible skin types
*** Compromised immunity
**** Transplant - 10x that of normal population
*** Environmental exposures
*** Underlying genetic disorders

** Pathophysiology
*** Arises from basal layer of epidermis and its appendages - from immature, pluripotent cells associated with the hair follicle
*** No precursor lesion
*** Classification (divide into two main groups)
**** Nonaggressive: keratotic, infundibulocystic, nodular (most common - almost 80% of all BCCs), superficial (15% of all BCCs)
***** Generally managed with 5mm resection margins
**** Aggressive: micronodular, infiltrative, sclerosing, morpheaform, desmoplastic, basosquamous (this is a 'collision' type lesion containing parts SCC/keratinizing squamous component, treated according to differentiation of the SCC component)
** Clinically

*** 86% occur on head
*** Rare on hand, penis and lower lip - more likely SCC here
*** Lesions on upper lip are almost always BCC
*** Most common malignant eyelid tumour
*** Nodular subtype appearance is pearly, dome-shaped, well-circumscribed, telangiectasias, possible ulceration
****
*** Superficial BCC
**** Macular growth pattern
**** Appears similar to psoriasis/tinea/eczema
****
*** Morphoeic/sclerosing BCC
**** Usually mid-facial
**** Waxy, scar-like plaque with indistinct borders
**** Wide and deep subclinical extension
****

** Treatment

Treatment:

** First, determine whether there is a HIGH or LOW risk of recurrence

{| class="wikitable"
|
|Low
|High
|-
|Size
|<10mm in high-risk areas (see fig)
|Any size in high-risk areas of face (fusion planes and nasolabial folds)
|-
|Size
|<20mm in low-risk areas
|>=10mm in other areas of face/neck/pretibia
|-
|
|
|>=20mm in all other body areas
|-
|Histo
|Nodular or superficial histopathology pattern
|micronodular, infiltrative, sclerosing, morpheaform, desmoplastic, basosquamous
|-
|Perineural 
|Lack of perineural invasion
|Perineural invasion
|-
|
|Primary lesion (not recurrent)
|Recurrent
|-
|
|Well-defined clinical borders
|Scarred area (Marjolin's ulcer)
|-
|
|No history of radiotherapy at site
|Site of prior radiotherapy
|-
|
|Immunocompetent patient
|Immunocompromised
|}

** Workup:

*** Lesions with large nerve perineural involvement should have a Gadolinium MRI to exclude perineural spread
*** Lack of guidelines on when to image looking for mets

** Surgery:

*** For low-risk BCC in non-critical areas of head/neck, surgery with 4-5mm margins is first-line

**** Generally easy to tell where the tumour ends, except for infiltrative and morphoeic BCCs
**** Consider Moh's microsurgery for tissue conservation

*** For high-risk BCC, MMS is recommended if available
*** Margins:
**** Non-critical head/neck areas and low-risk: 4-5mm
**** For high-risk, >5mm is recommended
*** SLNB is unnecessary, as lymph node metastases are very rare

** Medical:

*** If surgery is not preferred, try topical imiquimod or fluorouracil (see above under SCC section for details)
*** For locally advanced or metastatic BCC, hedgehog inhibitors can be used