Sirolimus, a mechanistic target of rapamycin (mTOR) inhibitor, is approved for the treatment of LMs in the US and other countries.3 In Japan, sirolimus was approved in 2023 but only for intractable cases, following multiple reports of efficacy.4 However, sirolimus use is limited by the risk of serious adverse events, including thrombocytopenia, lymphopenia, hyperlipidemia, infection, and cardiac complications. Here, MTOR is linked to hyperlipidemia.