Mohs micrographic surgery for keratinocyte carcinomas: clinicopathological predictors of the number of stages.

Background: The number of Mohs stages needed to remove a keratinocyte carcinoma affects resource use, expenses, and repair complexity. This study aimed to identify clinicopathological predictors associated with increased or decreased stages and areas for further research. Methods: A retrospective review was conducted from a single private practice with two Mohs surgeons of 2788 consecutive Mohs cases between January 2017 and December 2021, analyzing the average number of stages taken versus national norms (P = 0.21) and subgroups using unpaired t tests (*<0.05). Results: Several tumor features were significantly associated with fewer stages: squamous cell carcinomas, Mohs appropriate use criteria score of 7 or 8, preoperative size <0.25 cm2, tumors on the lips and extremities (including hands/fingers), and smoking. Clinicopathological features significantly associated with more stages included Mohs appropriate use criteria score of 9, recurrent skin cancers, basal cell carcinomas, tumor size of 2.25-3.99 cm2, cancers on ears, solid organ transplant patients, treatment delays >180 days, and patients ≥90 years old. Conclusions: Significant predictors exist for both increased and decreased numbers of Mohs micrographic surgery stages required to eradicate a tumor, which may help Mohs surgeons facilitate, plan, and allocate resources more effectively. Areas for further research in Mohs micrographic surgery are identified.

Merkel cell carcinoma in a vein graft donor site.

The development of malignancies in graft donor sites is rare and may be caused by de novo malignancies as well as metastatic and iatrogenic spread. Malignancies in graft donor sites are distinguished from Marjolin ulcers by some investigators because they occur in healed surgical wounds rather than in chronic wounds or unstable scars and tend to occur sooner after injury. We present a unique case of Merkel cell carcinoma (MCC) developing in a vein graft donor site 18 years after vein harvesting.

Severe cutaneous reaction to photodynamic therapy with blue light.

Photodynamic therapy (PDT) has been considered a safe and efficacious treatment for actinic keratoses (AKs) of the scalp and face. The procedure involves exposing a patient to a blue light source 1-4 hours after application of photosensitizing aminolevulinic acid (ALA) at a dose of 10 J/cm2 for up to 1000 seconds.(1,2) We suggest that amount of exposure time and area of exposure should be stratified according to baseline photodamage.