Introduction: Peripheral margin clearance of atypical junctional melanocytic hyperplasia (AJMH) lesions prior to definitive reconstruction presents a significant challenge. Although adequate deep margins are easily obtained, the peripheral margins can be difficult to clear. Traditional pathologic evaluation of wide local excisions often fails to detect discrete lesional extensions, and frozen sections and traditional Mohs micrographic surgery are unreliable. Current practice involves intermediate coverage of large defects with skin grafts, homograft, or dressings until permanent pathological evaluation is completed. The “square” technique offers the advantage of complete peripheral margin control prior to definitive lesion excision and allows for staged primary reconstruction with the optimal technique.

Methods: A multidisciplinary team, including an experienced dermatologist, dermatopathologist and reconstructive surgeon is utilized. Patients with biopsy-proven lentigo maligna melanoma or AJMH are first treated by Mohs-trained dermatologists. In an office setting, geometric peripheral margin excision is performed using a two-bladed scalpel. Repeat peripheral margin excision is performed until permanent section control is gained, as determined by experienced dermatopathologists. Definitive excision of the central lesion and reconstruction are then performed by a plastic surgeon, without the intermediate need for temporary wound coverage.

Results: Twenty-five consecutive cases by a single plastic surgeon were reviewed. Mean patient age was 63 years, of which 52% were male. The mean number of staged “square” procedures required for margin clearance was 2.1 +/- 1.1 (range 1-5 stages). Lesions involved the cheek in 19 patients (76%), the nose in 4 patients (16%), the lip in one patient (4%), and the forehead in one patient (4%). The average size of excision for cheek lesions was 22 cm2. Procedures used in reconstruction included eight cervicofacial flaps (32%), six full-thickness skin grafts (24%), six rhomboid flaps (24%), three nasolabial flaps (12%), one forehead flap (4%) and one local tissue rearrangement (4%). Complications included partial loss of a full-thickness skin graft, partial loss of two local flaps, one positive margin post-reconstruction, and one case of hypertrophic scar formation. One patient required re-excision for a positive deep margin on the central lesion.

Conclusions: AJMH is an ill-defined lesion clinically, often requiring greater than 0.5 cm margins for peripheral control. The use of the “square” technique in the management of AJMH provides certainty of margin control prior to definitive excision and reconstruction. Thus, optimal reconstructive options can be pursued in a staged, elective fashion, without the need for intermediate additional procedures such as temporary skin graft coverage or dressing changes.