Dermatofibrosarcoma protuberans treated by micrographic surgery

Dermatofibrosarcoma protuberans is an uncommon cutaneous tumour which rarely metastasises. However, local recurrence following apparently adequate surgical excision is well recognised, presumably as a result of sub-clinical contiguous growth, for which micrographically controlled excision would be a logical treatment. A retrospective study of all patients treated by micrographic surgery, from April 1995–March 2000, at a tertiary skin oncology centre. Twenty-one patients (11 males), age 14 to 71 years with dermatofibrosarcoma protuberans on the trunk (10 patients), groin (four), head and neck (four), and limbs (three) were treated. In 15 patients one micrographic layer cleared the tumour, and four were cleared with two layers. For one patient the second stage was completed by conventional excision guided by positive margins. Another patient with a multiply recurrent perineal dermatofibrosarcoma protuberans, not cleared in one area after two layers, died from a pulmonary embolus before total clearance could be achieved. There was no correlation between tumour size and lateral excision margin. No recurrence was observed during the follow-up, from 21 to 80 months, median 47 months. The study provides further support for micrographic surgery as the treatment of choice for dermatofibrosarcoma protuberans

Predicting Worst-Case Execution Time Trends in Long-Lived Real-Time Systems

In some long-lived real-time systems, it is not uncommon to see that the execution times of some tasks may exhibit trends. For hard and firm real-time systems, it is important to ensure these trends will not jeopardize the system. In this paper, we first introduce the notion of dynamic worst-case execution time (dWCET), which forms a new perspective that could help a system to predict potential timing failures and optimize resource allocations. We then have a comprehensive review of trend prediction methods. In the evaluation, we make a comparative study of dWCET trend prediction. Four prediction methods, combined with three data selection processes, are applied in an evaluation framework. The result shows the importance of applying data preprocessing and suggests that non-parametric estimators perform better than parametric methods

Surgical-Treatment of Dermatofibrosarcoma Protuberans - a Retrospective Study of 20 Cases with Review of Literature

The clinicopathological features and results of surgical treatment of 20 patients with dermatofibrosarcoma protuberans (DFSP) were reviewed. All patients have been observed until the present time or death. The primary treatment usually consisted of marginal, wide or radical excision. Re-excision because of recurrence was performed in six of the 20 patients who were treated primarily only by marginal excision. Following re-excision two patients have remained disease-free until the present, the other four of these six patients had a second recurrence. Three of these four patients with a second relapse were successfully treated by excision. Although six patients out of 20 had 13 recurrences at the site of primary therapy, no patient developed lymph node or distant metastases. To date, none of the remaining 14 patients has had recurrence, all having been treated by excision of from 1 to 5 cm, the mean follow-up time was 8.75 years. Based on our data, the high recurrence rate after marginal surgical treatment implies an initial radical resection