Dermoscopy of porokeratosis: results from a multicentre study of the International Dermoscopy Society.

BACKGROUND: The diagnosis of porokeratosis can be challenging, and knowledge about its dermoscopic features is limited. OBJECTIVES: To describe the dermoscopic features of porokeratosis of Mibelli and disseminated superficial actinic porokeratosis (DSAP) and the frequency of these features in a larger case series. The interobserver concordance was also assessed. METHODS: In this retrospective cohort study, members of the International Dermoscopy Society contributed macroscopic and dermoscopic images of histopathologically verified cases of porokeratosis of Mibelli or DSAP. Three observers independently reviewed the collected images to identify the presence of predefined dermoscopic features. Following this, a consensus meeting was held to agree upon which dermoscopic features were present in each lesion. RESULTS: In total, 78 clinical and dermoscopic images of porokeratoses were collected. The most common dermoscopic feature was keratin rim, which was present in 74 lesions (92.3%). The most common vascular structures were dotted or glomerular vessels which were present in almost half of the cases (48.7%). Other relatively frequent dermoscopic findings were as follows: non-peripheral scales (44.9%), grey-brown dots or pigmentation along the keratin rim (38.5%), and light-brown pigmentation within the keratin rim (33.3%). Shiny white structures and blood spots or erosions along the keratin rim were findings never before described in porokeratosis and were detected in 16.7% and 17.9% of the lesions, respectively. Dermoscopic findings in porokeratosis of Mibelli and DSAP were similar except for fewer blood spots or erosions along the keratin rim and more light-brown pigmentation within the keratin rim in DSAP. The interobserver concordance ranged from 0.44 (moderate) to 0.84 (almost perfect). CONCLUSIONS: The dermoscopic hallmark of porokeratosis is the keratin rim, a finding also allowing for almost perfect interobserver agreement. Pigmentation or erosions along the keratin rim, vascular structures, as well as scales, pigmentation or shiny white structures within the keratin rim are additional dermoscopic clues.

Effectiveness of photodynamic therapy in Bowen's disease: a retrospective observational study in 423 lesions.

BACKGROUND: Photodynamic therapy (PDT) is a well-known technique that is often used for treating superficial precancerous and cancerous skin lesions. However, only a handful of studies, with a relatively small number of treated lesions, have been carried out on the effectiveness of PDT for Bowen's disease (BD). OBJECTIVES: This study aimed to assess the effectiveness and recurrence risk of PDT in the treatment of BD. The secondary objectives were to determine what factors affected the response rates and the cosmetic result of the treatment. METHOD: In this retrospective observational study, the electronic patient charts at Sahlgrenska University Hospital (SUH) in Gothenburg, Sweden, were searched to find all patients diagnosed with BD who were treated with PDT between 1 January 2002 and 31 December 2014. Data were collected regarding clinical response at the first follow-up visit, recurrences during later follow-up visits and other relevant patient and tumour characteristics. RESULTS: In total, 423 BD lesions in 335 patients were included in the study. The mean FU duration was 11.2 months (range 0.2-151 months). The complete response rate at the first FU visit was 77.5% for all BD lesions. During later FU visits, another 60 recurrences were observed, which resulted in a recurrence rate of 18.3%. Thus, the overall clearance rate after FU was 63.4% for all BD lesions. Significant risk factors for unsuccessful treatment in this study were large lesion size (>2 cm) and a single PDT session. CONCLUSION: This study shows that PDT is a relatively effective treatment modality for BD.

Merkel cell carcinoma incidence is increasing in Sweden.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare aggressive neuroectodermal skin cancer with a high recurrence rate and a high mortality rate. Risk factors for MCC are reported to include high age, UV exposure, Caucasian skin type and immunosuppression. The incidence is reported to be increasing. OBJECTIVE: The purpose of this study was to describe a Swedish cohort and calculate incidence. METHODS: The study design is a retrospective cohort study of population-based data for MCC collected by the Swedish Cancer Registry to determine the incidence of MCC in Sweden and the clinical characteristics of these tumours including demographics, TNM classification, body part distribution and overall survival after diagnosis. De-identified data were collected from 1993 to 2012. RESULTS: A total of 606 cases of MCC were identified during the study period. The median age was 81 years (range 21-99) and a majority, 54.4% were women but age-adjusted incidence is higher in men. The incidence (per 100,000) of MCC in Sweden in 1993-2012 increased from 0.09 to 0.20 for men and 0.12-0.17 for women, adjusted for age to the world standard population. For the both sexes, the increase was from 0.11 to 0.19 per 100 000, an increase of 73%. The most common site of the primary tumour was the head and neck, with 51.8% of the cases. The size of the tumour was <5 cm in 82.1% of the cases. The majority of the tumours (90.7%) had no known lymphatic spread and only a few patients had confirmed distant metastases (2.9%) when diagnosed. CONCLUSIONS: MCC is a rare disease in Sweden, but the incidence is increasing. This study supports the finding that high age, male sex and UV exposure are risk factors for MCCs. Interventions are required to increase awareness of MCC among clinicians and the public.