A 10-year review of surgical management of dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare skin cancer. Standard treatment in the UK is either wide local excision (WLE) or Mohs micrographic surgery (MMS). It is unclear which approach has the lower recurrence rate. OBJECTIVES: We undertook a retrospective comparative review of surgical management of DFSP in the UK National Health Service in order to define (i) current surgical practice for primary and recurrent DFSP, (ii) local recurrence rates for primary DFSP and (iii) survival outcomes for DFSP. METHODS: A retrospective clinical case-note review of patients with histologically confirmed DFSP (January 2004 to December 2013) who have undergone surgical treatment. RESULTS: The surgical management of 483 primary and 64 recurrent DFSP in 11 plastic surgery and 15 dermatology departments was analysed. Almost 75% of primary DFSP (n = 362) were treated with WLE and 20% (n = 97) with MMS. For recurrent DFSP, 69% (n = 44) and 23% (n = 15) of patients underwent WLE and MMS, respectively. Recurrent primary DFSP occurred in six patients after WLE and none after MMS. The median follow-up time was 25·5 months (interquartile range 6·8-45·1) for new and 19·8 (IQR 4·5-44·5) for recurrent DFSP [Correction added on 1 Feb 2021, after first online publication: 4.8 years (interquartile range 3.5-5.8) was incorrect], with eight reported deaths during the follow-up analysis period (one confirmed to be DFSP related). CONCLUSIONS: WLE was the most common surgical modality used to treat DFSP across the UK. The local recurrence rate was very low, occurring only after WLE. Although a prospective randomized controlled trial may provide more definitive outcomes, in the absence of a clearly superior surgical modality, treatment decisions should be based on patient preference, clinical expertise and cost.

Basal cell carcinoma of the vulva: treatment with Mohs micrographic surgery.

Vulval basal cell carcinomas (BCCs) are rare, representing < 5% of vulval malignancies and 1% of all BCCs. They often present with nonspecific symptoms and features that lead to large, poorly circumscribed and late-presenting lesions. Current and conventional treatments used to treat vulval BCC include cryotherapy, imiquimod and excision. However, recurrence rates as high as 20% have been reported with these treatments. Furthermore, there are no current clinical guidelines for their management. We present the first reported series of patients with vulval BCC treated with Mohs micrographic surgery (MMS). We report seven cases of vulval BCC treated with MMS at a tertiary referral centre over 3 years. Follow-up was performed at 3 months and up to 3 years. Our series demonstrates that there were no postoperative complications, functional sequelae or recurrences up to the 3-year follow-up. We therefore recommend that MMS should be considered in the management of vulval BCCs.

Spatial constraints govern competition of mutant clones in human epidermis.

Deep sequencing can detect somatic DNA mutations in tissues permitting inference of clonal relationships. This has been applied to human epidermis, where sun exposure leads to the accumulation of mutations and an increased risk of skin cancer. However, previous studies have yielded conflicting conclusions about the relative importance of positive selection and neutral drift in clonal evolution. Here, we sequenced larger areas of skin than previously, focusing on cancer-prone skin spanning five decades of life. The mutant clones identified were too large to be accounted for solely by neutral drift. Rather, using mathematical modelling and computational lattice-based simulations, we show that observed clone size distributions can be explained by a combination of neutral drift and stochastic nucleation of mutations at the boundary of expanding mutant clones that have a competitive advantage. These findings demonstrate that spatial context and cell competition cooperate to determine the fate of a mutant stem cell.

Five-year recurrence rate of lentigo maligna after treatment with imiquimod.

BACKGROUND: The current recommended treatment for lentigo maligna (LM) is surgical resection, which can cause significant scarring. The reported recurrence rate after Mohs micrographic surgery is 0-6·25%. There is little published data on long-term outcome after imiquimod therapy. Several reports record progression to LM melanoma during treatment. Clinical assessment of clearance is difficult. Histological confirmation is preferred but risks sampling error and missing areas of invasion. Confocal microscopy can be used to assess entire lesions. OBJECTIVES: To assess the 5-year recurrence rate of LM after imiquimod treatment. METHODS: Forty patients with LM were treated with imiquimod between 2002 and 2007. Their previous treatments included cryotherapy, incomplete surgical excision and radiotherapy. All applied imiquimod three times per week for 6 weeks; 25 (62·5%) experienced inflammation. The other 15 (37·5%) then applied imiquimod five times per week for a further 4 weeks; all experienced inflammation. All patients were subsequently examined and biopsied. Clinical clearance did not always correlate with histological clearance. Eleven patients (27·5%) had residual LM on histology and underwent surgical excision. At the time of this study, three patients had died (deaths were unrelated to LM). Eighteen of the 27 patients (66·7%) who were clear on biopsy after imiquimod attended for the study and were assessed using confocal microscopy (Vivascope 1500 and 3000). RESULTS: The recurrence rate of LM in patients who were clear on histology after imiquimod treatment who attended for this follow-up study was 0% (n = 18). CONCLUSIONS: Imiquimod is an effective long-term treatment for LM. Its use avoids potentially disfiguring surgical resection.

Automated registration of optical coherence tomography and dermoscopy in the assessment of sub-clinical spread in basal cell carcinoma.

Optical coherence tomography (OCT) has been shown to be of clinical value in imaging basal cell carcinoma (BCC). A novel dual OCT-video imaging system, providing automated registration of OCT and dermoscopy, has been developed to assess the potential of OCT in measuring the degree of sub-clinical spread of BCC. Seventeen patients selected for Mohs micrographic surgery (MMS) for BCC were recruited to the study. The extent of BCC infiltration beyond a segment of the clinically assessed pre-surgical border was evaluated using OCT. Sufficiently accurate (<0.5 mm) registration of OCT and dermoscopy images was achieved in 9 patients. The location of the OCT-assessed BCC border was also compared with that of the final surgical defect. Infiltration of BCC across the clinical border ranged from 0 mm to >2.5 mm. In addition, the OCT border lay between 0.5 mm and 2.0 mm inside the final MMS defect in those cases where this could be assessed. In one case, where the final MMS defect was over 17 mm from the clinical border, OCT showed >2.5 mm infiltration across the clinical border at the FOV limit. These results provide evidence that OCT allows more accurate assessment of sub-clinical spread of BCC than clinical observation alone. Such a capability may have clinical value in reducing the number of surgical stages in MMS for BCC. There may also be a role for OCT in aiding the selection of patients most suitable for MMS.