Introduction: This study aimed to (i) determine rapid weight loss (RWL) practices among Malaysian elite combat sports athletes and (ii) examine the relationship between the characteristics of athletes, self-reported history of weight loss, perceived influence on weight loss and RWL practices. Methods: This was a cross-sectional study conducted at the Malaysian National Sports Institute among elite combat sports athletes (n=40) recruited via a convenience sampling method. The athletes completed a self-administered validated Rapid Weight Loss Questionnaire. Each response was provided a score and the total RWL score corresponded to the aggressiveness of weight management methods. Partial correlations were used to assess the relationships between total RWL score and independent variables. Results: The prevalence of RWL among the athletes was high (92.5%). Training with rubber or plastic suits (62.2%) and meal-skipping (27.0%) were the most common RWL techniques practised by the respondents. Aggressive weight-cutting as depicted by a higher total RWL score that correlated with most weight ever lost, duration taken to lose weight, influence of training colleagues and coaches, BMI, current weight and post-competition weight regain (all p<0.05). In contrast, negative correlations were seen between total RWL score, and the age at which the athletes began competing (p<0.001), duration of competition (p<0.001), age at first participation (p<0.05), duration of participation (p<0.05) and influence of nutritionists on weight loss (p<0.05). Conclusion: A high prevalence of aggressive weight loss among elite combat sports athletes and its association with perceived influence of sports professionals, colleagues and actual weight-related characteristics are of great concern.

Objective:To study clinical pathological characteristics, immunohistochemical, molecular genetical changes and prognosis in pediatric eosinophilic solid and cystic renal cell carcinoma (ESC RCC) with TSC2 gene mutations.Methods:The tissue samples were collected from two pediatric ESC RCC patients between 2017 and 2018. The tissues were subjected to histological examination and immunohistochemistry using EnVision system. The TFE3, TFEB gene rearrangements were tested using FISH and molecular genetic study. The paraffin sections were used for DNA extraction, PCR amplification and NGS sequencing.Results:The two patients with ESC RCC were both male, aged at 9 years and 8 months, and 13 years, respectively. The tumors were from the right kidney, 5 cm and 7 cm in size, respectively, with solid and cystic changes in cross section, and grey-reddish or grey-whitish fish meat appearance. Microscopic observation revealed the tumors had fibrous capsules, which were infiltrated by the tumor cells. The tumor cells were diffusely distributed, round-shaped, or polygon-shaped, and had voluminous cytoplasm, eosinophilic cytoplasm, various sizes of vacuoles and clear cell-like appearance. There were papillary structures in some areas, with visible fiber septa. The nuclei were round and vesicular, with multi-nucleated cells and megakaryocytes. The mitoses were not seen. A few cystic structures were visible in different sizes, and capsule walls were covered with a single layer of spike-like tumor cells. Thick-walled blood vessels were seen in the stroma, with focal lymphocytic infiltration, eosinophilic necrosis, calcifications and cholesterol crystals. Immunohistochemistry of the tumor cells was positive for PAX8 (diffuse), CK20 (focal), CKpan (focal), CK10 (1 focal, 1 diffuse), INI1, vimentin, CD68, and Ki-67 (5%~10%); the tumor cells were negative for HMB45, S-100, Melan A, p53, desmin, TFE3, CK7, CK19, EMA, CD56, CgA, Syn, CD30, CD117, WT1 and SMA. Molecular genetic study showed that TFE3 and TFEB gene rearrangements were not detected by FISH. NGS sequencing showed TSC2 p.Lys574Ter (0.198) was found in patient one and TSC2 p.Arg406Ter (0.355) in patient two.Conclusions:ESC RCC in children is a rare disease, and can be misdiagnosed easily. It has unique pathological characteristics, and immunohistochemical, molecular and genetic changes. The prognosis is relatively good.