We read with great interest the article “The relationship between renal sinus lipomatosis detected at abdominal computed tomography and abdominal visceral and subcutaneous fat accumulation and metabolic risk factors” authored by Yalçın et al. [1]. In this article, the relationship of abdominal visceral fat, subcutaneous fat, and metabolic factors with the development of renal sinus lipomatosis (RSL) was evaluated.

For the benefit of the readers of this esteemed journal, we request that the authors kindly elaborate on how the diagnosis of RSL was established. It will be interesting to know if any objective criteria were used to formulate the diagnosis of RSL or whether the study was based on subjective assessment alone. Renal sinus fat tends to increase with age, and only its excessive accumulation resulting in distortion of PCS would qualify it to be termed as RSL [2]. There may be no symptoms related to the distortion of PCS [3]. Secondly, obesity is a well-known risk factor for development of RSL [2]. Were the risk factors, i.e. hyper-tension, hypercholesterolaemia, deranged lipid profile, high glucose levels, and age independently evaluated to be causative factor for RSL? Because any elderly obese person would generally have all the above-mentioned derangements, it is essential to evaluate these factors independently to remove any form of bias or confounding factors. Patients with high abdominal visceral or subcutaneous fat were observed to have RSL in the present study. Kindly elaborate if there was any linear relationship amongst these, i.e. patients with higher abdominal fat were seen to have greater fat accumulation in renal sinuses. Repeated renal infections, ischaemia, or infarction are predisposing conditions for RSL. Were these ruled out in all subjects of the study group? Lastly, it would have been interesting to see if the patients were also evaluated for the decrease in renal sinus fat volume with decreasing trend of metabolic derangements either with treatment or lifestyle modification, which would have been more assuring for their causal relationship.

We once again congratulate the authors for their work on this rather understudied topic of RSL.