Mohs micrographic surgery.

Mohs micrographic surgery is an approach to skin cancer removal that aims to achieve the highest possible rates of cure and to minimize the size of the wound and consequent distortions at critical sites such as the eyes, ears, nose, and lips. Mohs micrographic surgery is a two-step, same-day procedure performed with local anesthetic. It involves removing the tumor in stages by histologically confirming clear margins on frozen sections and by addressing the resultant defect. Options for healing include second intent, primary closure, local flaps, interpolation flaps, and grafts. Larger tumors may require referral for reconstructive surgery. Mohs micrographic surgery is the treatment of choice for skin tumors in critical sites, large or recurrent tumors, tumors in sites of radiation therapy, and tumors with aggressive histologic features.

Histopathologic recognition of involved margins of lentigo maligna excised by staged excision: an interobserver comparison study.

OBJECTIVES: To assess interobserver and intraobserver concordance for identifying positive and negative margins in staged excisions of lentigo maligna and lentigo maligna melanoma and to determine if control biopsy specimens are useful to improve concordance. DESIGN: Retrospective, randomized interobserver and intraobserver comparison study of archived pathologic specimens. The study was conducted in 3 phases, and slides were evaluated blindly and independently by 5 pathologists: in phase 1, all slides were randomized and diagnosed as positive or negative. In phase 2, every third slide was evaluated again and diagnosed as positive or negative. In phase 3, slides were organized into cases, allowing evaluation of each margin in the context of the positive control (tumor from the center of the lesion) and negative control (control biopsy specimen), if available. SETTING: University referral center. STUDY MATERIAL: A total of 301 glass microscopic slides from 27 patients who underwent staged excision for lentigo maligna or lentigo maligna melanoma from March 1997 to April 2001. MAIN OUTCOME MEASURES: Interobserver and intraobserver concordance between original diagnoses and study diagnoses rendered on all slides by 5 pathologists. RESULTS: Phase 1 and 3 agreement was moderate (kappa range, 0.4-0.5). Phase 2 (intraobserver) agreement was moderate to good for all pathologists (kappa range, 0.6-0.9). Subset analysis revealed a statistically significant increase in agreement with the use of a control strip biopsy specimen for difficult slides. CONCLUSIONS: Interobserver concordance for margin analysis in lentigo maligna and lentigo maligna melanoma is moderate, and intraobserver concordance is moderate to good. A control strip biopsy specimen may improve concordance in some cases.

Histologic evaluation of lentigo maligna with permanent sections: implications regarding current guidelines.

BACKGROUND: Obtaining clear margins of resection of lentigo maligna (LM), a subtype of melanoma in situ, from sun-damaged skin of the head and neck continues to be a surgical challenge. The margins may be uncertain both clinically and histologically, causing difficulty in determining the surgical excision perimeter. OBJECTIVE: We sought to determine whether the current National Institutes of Health consensus conference (1992) recommendation of 5-mm margins is adequate for the removal of LM and to evaluate at what stage tumor-free margins are ultimately attained by using polygonal, staged excisions. METHODS: Ninety-two cases of LM were evaluated and treated in a university tertiary care setting. Straight-edge polygonal resections in a staged fashion of LM variants of MIS were evaluated by means of permanent serial histopathologic sections. Each stage of resection used a 5-mm margin. Specimens were color-coded and mapped. Any sites of tumor at resected margins were identified by a dermatopathologist and noted on the map of the excised specimen. Positive margins and areas with markedly atypical melanocytes were further resected, color-coded, mapped, and evaluated as previously described until margins free of tumor were attained. RESULTS: The patient distribution was 37% female and 63% male, with ages ranging from 24 to 100 years (median age, 70 years). Sixty-nine patients had a biopsy-proven diagnosis of LM involving the head and neck (75%), and 23 patients (25%) had LM elsewhere. Thirty-nine patients (42%) were tumor-free after one stage, 25 (27%) required 2 stages, 14 (15%) required 3 stages, 6 (7%) required 4 stages, and 8 (9%) needed 5 or more stages to achieve tumor-free margins. The central portion of the submitted polygonal excisions revealed an invasive component in 16% of cases. CONCLUSIONS: Use of polygonal perimeter excisions with serial histopathologic permanent sections in a staged fashion is an accurate and thorough method of evaluating and treating LM. This study demonstrates that the standard recommendation of 5-mm margins is adequate in less than 50% of cases and reiterates the need for the careful evaluation of peripheral margins in LM. Because an invasive component can be present and would alter recommended surgical depths and margins, all of the tumor should be submitted at the first stage rather than peripheral margins only.