Mohs Surgery Flashcards
What type of tumor growth pattern is amendable to Mohs surgery?
Contigeous growth, if there are skin lesions false-negative margins can occur! (angiosarc, and merkel cell are often not recommended for this reason
Why are Mohs stages cut on a bevel (45 degrees)?
So that the edges can be folded down and that epidermis can be seen on the same plane as the deep dermis margin. This allows visualization of the peripheral and deep margins simultaneously
What are high-risk areas where Mohs is indicated?
Periorbital, perinasal, periauricular, peroral, and hair-bearing scalp
What non-high risk skin areas still carry an indication for Mohs?
Digits, genitals (tissue sparing is key)
What are tumor characteristics that would trigger/justify a referral to Mohs?
Recurrent, high-risk areas, tissue-sparing areas, aggressive histologic subtypes of tumors (morpheaform BCC, micronodular or infiltrating BCC, basosquamous BCC, and high grade, poorly differentiated and or deeply penetrating SCC, desmoplastic or spindle cell SCC, and perineural invasion), large size (>2cm), poor defined clinical borders, rapid growth
What risk factors from the skin would qualify a referral to Mohs?
Prior exposure to ionizing radiation, chronic scar (Marjolin’s ulcer), and site of + margins on prior excision
What patient characteristics qualify a referral to Mohs?
Immunocompromised, underlying genetic syndrome (xeroderma pigmentosum, nevoid BCC syndrome, or Bazex-Dupre-Christol syndrome
What is Frey’s Syndrome?
Rare complication from Mohs where the auriculotemporal branch of CN V in the parotid region gets damage and this results in vasodilation and hyperhidrosis of the ipsilateral cheek when eating due to fusion with parasympathetic fibers
What is a useful marker for AFX that is usually positive?
CD10 (stains diffusely + in 95% of cases)
What is the differential for an AFX?
AFX, spindle cell melanoma, spindle cell SCC, DFSP, and leiomyosarcoma
What is the histology of AFX?
Spindle cells, epitheloid cells, and multinucleated giant cells in haphazard arrangement slammed against the epidermis. Mitotic figures are common and some of the giant cells can have a foamy appearence
How can the risk of air embolism be reduced when working on the scalp?
Patients should be in the prone or recumbent position and airtight dressings should be used between stages or prior to reconstruction
What is a rare, but catastrophic side effect large Mohs surgeries on the scalp w/ skull exposed?
Air embolism
Sx’s include: SOB, headache, seizures, confusion, and neurologic sx’s
If a resident get’s an accidental needlestick and the patient’s HIV status is unknown, can HIV prophylaxis be discontinued once the patient’s result comes back negative?
Yes, HIV prophylaxis can be discontinued once the negative result is discovered
What two treatments are appropriate for lentigo maligna/melanoma in-situ lentigo maligna subtype?
Mohs vs staged excision
