Pararectal Epidermal Inclusion Cyst in a Pediatric Patient.

Epidermal inclusion cysts, commonly found cutaneously, rarely manifest in the pelvis. They are typically asymptomatic and often occur following trauma or surgical interventions. Imaging modalities, notably computed tomography (CT) scans and magnetic resonance imaging (MRI), play a crucial diagnostic role. Herein, we report a rare case of a four-year-old female with a complicated medical and surgical history, presented with pain in the right gluteal region in the setting of past history of abscess drainage in the same area. Imaging revealed a cystic lesion in the right pararectal space and a fistula extending between the pelvic cavity and gluteal region. A laparotomy was performed, and a histopathologic examination confirmed the diagnosis of an epidermal inclusion cyst with no evidence of malignancy.

An Adaptive Multipopulation Differential Evolution With Dynamic Population Reduction.

Developing efficient evolutionary algorithms attracts many researchers due to the existence of optimization problems in numerous real-world applications. A new differential evolution algorithm, sTDE-dR, is proposed to improve the search quality, avoid premature convergence, and stagnation. The population is clustered in multiple tribes and utilizes an ensemble of different mutation and crossover strategies. In this algorithm, a competitive success-based scheme is introduced to determine the life cycle of each tribe and its participation ratio for the next generation. In each tribe, a different adaptive scheme is used to control the scaling factor and crossover rate. The mean success of each subgroup is used to calculate the ratio of its participation for the next generation. This guarantees that successful tribes with the best adaptive schemes are only the ones that guide the search toward the optimal solution. The population size is dynamically reduced using a dynamic reduction method. Comprehensive comparison of the proposed heuristic over a challenging set of benchmarks from the CEC2014 real parameter single objective competition against several state-of-the-art algorithms is performed. The results affirm robustness of the proposed approach compared to other state-of-the-art algorithms.