主要皮肤平滑肌肉肉瘤（LMS）是罕见的软组织肿瘤，分为两个亚型：皮肤型和皮下型。较深的肿瘤预后较差，需要更积极的治疗方法。相反，建议对皮肤型LMS采用更为保守的手术方法。目前，只有少数研究全面报道了临床手术和组织学切除边缘。因此，我们希望根据我们的经验和对现有文献的评论，提供基于切缘的建议。通过对皮肤LMS病例的回顾性病历回顾（1998-2019年），利用病理学/电子病历记录建立了组织学/手术切除边缘。经验丰富的皮肤病理学家根据世界卫生组织的分类进行诊断和分类。皮肤LMS队列（n = 35）：周边和深部组织学切缘平均为5.4mm（范围0.5-20mm）和5.6mm（范围0.1-14.5mm）。不完全切除率：31％（11/35）。没有复发。皮下LMS队列（n = 10）：周边和深部组织学切缘平均为5.7mm（范围0.2-14mm）和1.1mm（范围0.2-1.7mm）。不完全切除率：40％（4/10）。复发率：20％（2/10），尽管在1年后获得了组织学清除。在适当切除头皮LMS原发灶之后的1年，发生了一次肺转移。我们建议对于皮肤LMS，应在初始切除或涉及/接近组织学周边和/或深部切缘（即<1mm）的瘢痕重新切除时，采用5-10mm（根据病变大小而定）的临床切缘。对于皮下LMS，建议采用15-20mm（根据病变大小而定）的临床切缘，以实现10mm的周边组织学清除，并达到负性深度切缘（即>1mm），直至骨膜/筋膜/肌肉，根据解剖位置而定。如果未能实现这一目标，则建议重新切除。然而，需要进行前瞻性研究以获得最佳指导。©2023年作者。由牛津大学出版社代表英国皮肤科学会发表。版权所有。如需授权，请发送电子邮件至：journals.permissions@oup.com。

Primary cutaneous leiomyosarcomas (LMS) are rare soft tissue tumours with two subtypes: dermal and subcutaneous. As deeper tumours confer a worse prognosis, they require a more aggressive approach. Conversely, a more conservative surgical approach for dermal LMS has been suggested. Few studies have comprehensively reported both clinical surgical and histological excision margins. We therefore sought to provide margin recommendations based on our experience and review of existing literature.Retrospective case-note review (1998-2019) of cutaneous LMS management was undertaken to establish histological/surgical margins using pathology/electronic patient records. The diagnosis was made and classified according to the WHO classification by an experienced Dermatopathologist.Dermal LMS cohort (n = 35): mean peripheral and deep histological margins were 5.4 mm (range 0.5-20 mm) and 5.6 mm (range 0.1-14.5 mm), respectively. Incomplete excision rate: 31% (11/35). There were no recurrences. Subcutaneous LMS cohort (n = 10): mean peripheral and deep histological margins were 5.7 mm (range 0.2-14 mm) and 1.1 mm (range 0.2-1.7 mm), respectively. Incomplete excision rate: 40% (4/10). Recurrence rate: 20% (2/10) despite achieving histological clearance after 1 year. One lung metastasis occurred 1 year following an adequately excised primary scalp LMS.We propose that for dermal LMS, a clinical margin of 5-10 mm (depending on size of lesion) at the initial excision or at scar re-excision following involved/close histological peripheral and/or deep margins (i.e. < 1 mm) is undertaken. For subcutaneous LMS, a clinical margin of 15-20 mm (depending on size of lesion) to achieve a peripheral histological clearance of 10 mm and negative deep margin (i.e. > 1 mm) down to periosteum/fascia/muscle according to anatomical site is suggested. If this is not achieved, a re-excision would be recommended. However, prospective studies are needed for optimal guidance.© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.