Wide Local Excision or Mohs Micrographic Surgery for Primary Dermatofibrosarcoma Protuberans

Mohs micrographic surgery: a review of indications, technique, outcomes, and considerations

Mohs micrographic surgery is a specialized form of skin cancer surgery that has the highest cure rates for several cutaneous malignancies. Certain skin cancers can have small extensions or “roots” that may be missed if an excised tumor is serially cross-sectioned in a “bread-loaf” fashion, commonly performed on excision specimens. The method of Mohs micrographic surgery is unique in that the dermatologist (Mohs surgeon) acts as both surgeon and pathologist, from the preoperative considerations until the reconstruction. Since Dr. Mohs’s initial work in the 1930s, the practice of Mohs micrographic surgery has become increasingly widespread among the dermatologic surgery community worldwide and is considered the treatment of choice for many common and uncommon cutaneous neoplasms. Mohs micrographic surgery spares the maximal amount of normal tissue and is a safe procedure with very few complications, most of them managed by Mohs surgeons in their offices. Mohs micrographic surgery is the standard of care for high risks basal cell carcinomas and cutaneous squamous cell carcinoma and is commonly and increasingly used for melanoma and other rare tumors with superior cure rates. This review better familiarizes the dermatologists with the technique, explains the difference between Mohs micrographic surgery and wide local excision, and discusses its main indications.

Understanding Mohs Micrographic Surgery: A Review and Practical Guide for the Nondermatologist

The incidence and diagnosis of cutaneous malignancies are steadily rising. In addition, with the aging population and increasing use of organ transplant and immunosuppressive medications, subsets of patients are now more susceptible to skin cancer. Mohs micrographic surgery (MMS) has become the standard of care for the treatment of high-risk nonmelanoma skin cancers and is increasingly used to treat melanoma. Mohs micrographic surgery has the highest cure rates, spares the maximal amount of normal tissue, and is cost-effective for the treatment of cutaneous malignancies. As in other medical fields, appropriate use criteria were developed for MMS and have become an evolving guideline for determining which patients and tumors are appropriate for referral to MMS. Patients with cutaneous malignancies often require multidisciplinary care. With the changing landscape of medicine and the rapidly increasing incidence of skin cancer, primary care providers and specialists who do not commonly manage cutaneous malignancies will need to have an understanding of MMS and its role in patient care. This review better familiarizes the medical community with the practice of MMS, its utilization and capabilities, differences from wide excision and vertical section pathology, and cost-effectiveness, and it guides practitioners in the process of appropriately evaluating and determining when patients with skin cancer might be appropriate candidates for MMS.

Positive margins in excised dermatofibrosarcoma protuberans: a study of 58 cases treated with slow-Mohs surgery

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is characterized by unpredictable subclinical extension, meaning that positive margins are frequently detected following conventional surgical excision.

OBJECTIVE

To study the presence or absence of residual tumour in DFSP with positive margins after conventional surgery and identify possible predictors of residual tumour or clear margins following a single Mohs micrographic surgery (MMS) stage.

METHODS

A retrospective study of patients with DFSP and positive margins following conventional excision referred for MMS was performed. We studied gender, age, tumour site, time from presentation to diagnosis, and affected margins.

RESULTS

We studied 58 cases, 35 (60.3%) of which had histological evidence of residual tumour. Tumours of the head and neck were significantly associated with the persistence of tumour. A single MMS stage was sufficient to achieve clearance in the majority of cases (n = 46). All tumours with lateral involvement only were resolved with a single Mohs stage.

CONCLUSIONS

DFSPs with positive margins after conventional surgical excision should undergo re-excision because the majority have histologic evidence of residual tumour. Re-excision with 1-cm margins beyond the scar could be an option in certain tumour sites, particularly when it is known which margins are involved.