The "Rule of 10s" versus the "Rule of 2s": High complication rates after conventional excision with postoperative margin assessment of specialty site versus trunk and proximal extremity melanomas.

Specialty site melanomas on the head and neck, hands and feet, genitalia, and pretibial leg have higher rates of surgical complications after conventional excision with postoperative margin assessment (CE-POMA) compared to trunk and proximal extremity (T&PE) melanomas. The "rule of 10s" describes complication rates after CE-POMA of specialty site melanomas: ∼10% risk of upstaging, ∼10% risk of positive excision margins, ∼10% risk of local recurrence, and ∼10-fold increased likelihood of reconstruction with a flap or graft. T&PE melanomas encounter these complications at a lower rate, according to the "rule of 2s." Mohs micrographic surgery (MMS) with frozen section melanocytic immunostains (MMS-I) and slow Mohs decrease complications for surgery of specialty site melanomas by detecting upstaging and confirming tumor removal with comprehensive microscopic margin assessment prior to reconstruction. This review article summarizes information that is important to counsel melanoma patients about surgical treatment options and to encourage development of consensus guidelines with clear indications for MMS-I or slow Mohs.