DEAR EDITOR, Recurrence rates following conventional surgery for lentigo maligna (LM)a form of in situ melanomaand lentigo maligna melanoma (LMM)the invasive form of LM have previously been reported as between 7% and 15%. 1,2 We aim to present our single-centre experience with LM and LMM, focusing on clinical and pathological characteristics including recurrence and survival analysis.This monocentric study was performed at the Skin Cancer Center Ruhr-University (Bochum, North Rhine-Westphalia, Germany). The study was approved by the ethics review board of the Ruhr-University Bochum. We assessed the records of patients with LM and LMM from 2000 to 2012. Clinicopathological parameters such as age, sex, anatomical site of primary, melanoma subtype, Clark level, tumour regression, ulceration and thickness (Breslow) were analysed. Follow-up data were collected using chart review and by contacting resident practitioners and dermatologists. LM and LMM were entirely removed with a small excision margin and then assessed by micrographically controlled histology. All tumours were stained with haematoxylin and eosin. Immunohistochemistry included staining with S100 and Melan-A/MART-1 (melanoma-associated antigen recognized by T cells). All melanomas had been assessed by two senior dermatohistopathologists.Patients with LMM of tumour thickness ≥ 1 mm and/or ulcerated LMM (> 0Á75 mm) underwent sentinel lymph node biopsy. Patients with positive sentinel lymph nodes were treated with complete lymph node dissection and high-dose interferon-a2b. Data analysis was performed using the statistical package MedCalc Software (MedCalc, Mariakerke, Belgium). Non-normally distributed data were expressed as median and range. Data were analysed using the v 2 -test. Local recurrencefree survival and overall survival were examined using the Kaplan-Meier method and Cox regression analysis. Survival curves were calculated from the time of diagnosis of the primary melanoma, and were considered censored for patients alive at the last follow-up, or in the event of nonmelanomarelated deaths or unavailable data. P-values < 0Á05 were considered significant.Data were available for 270 patients [122 (45Á2%) female; 148 (54Á8%) male]; median age 80 years (range 47-102); with LM (124/270, 45Á9%) or LMM (146/270, 54Á1%). The median LMM tumour thickness was 0Á35 mm (range 0Á1-6Á9), and Clark level was II in 88 patients, III in 30, IV in 27 and V in one patient. Overall 133 of 146 patients (91%) had LMM with tumour thickness < 1 mm. Ulceration was observed in five patients (1Á9%), and regression was not observed (Table 1). In total 241 of 270 tumours (89Á3%) AJCC, American Joint Committee on Cancer. a Mean follow-up 64Á4 months (range 5-151).

Summary Recurrence rates of both lentigo maligna (LM) and lentigo maligna melanoma (LMM) following conventional surgery are usually relatively high. We aimed to assess the frequencies of melanocytes in tumour‐free margins around LM/LMM using soluble adenylyl cyclase (sAC) immunohistochemistry, and to compare these with those of matched healthy contralateral skin. Using the primary mouse‐anti‐human sAC antibody R21, we evaluated pan‐nuclear melanocytic R21 immunostaining, and found that it was significantly (P < 0.001) higher in peritumoural melanocytes (median 20%; range 0–100%) than in contralateral healthy skin (mean 0%; range 0–20%). Accordingly, there was no correlation between peritumoural and contralateral R21 immunoreactivity (r = 0.12; P = 0.18). In conclusion, melanocytic R21 immunoreactivity in melanocytes is higher in tumour‐free margins around LM/LMM than in site‐matched contralateral skin. This observation may indicate that the biology of ‘healthy’‐appearing melanocytes around LM/LMM might be different from that of truly benign melanocytes.