This study has several parts and involves taking a study drug called alpelisib. Some participants enrolled into Stage 2 will receive a placebo for the first part of the study (24 weeks) and will then receive the study drug. The purpose of this study is to find out if the study drug is safe and effective (can help) people with a confirmed diagnosis of lymphatic malformation (LyM) and a documented mutation in the PIK3CA gene

This study aims to explore a new type of magnetic resonance imaging (MRI) called Chemical Exchange Saturation Transfer (CEST) in children aged 6-18 years with brain tumors. An MRI is a machine that takes detailed pictures of the brain. The CEST MRI used in this study is still being tested and has not been approved by the FDA yet. The study wants to find out if this new type of MRI can help doctors evaluate brain tumors. CEST MRI creates images using water molecules and protons in the brain. Early research shows that CEST could be helpful in understanding brain tumor changes.

This study will enroll 5 participants.

This study involves taking a study drug called venetoclax with or without standard of care chemotherapy. The overall goal of this study is to see if adding venetoclax to standard chemotherapy leads to improved survival for children and young adults with relapsed acute myeloid leukemia (AML). The study may last up to 9 years and will enroll male and female patients from the ages of 29 days to 21 years of age.

Children (less than 10 years of age) are eligible if they have been diagnosed with either a medulloblastoma tumor or CNS embryonal tumors of the brain or spinal cord. The standard approach to the treatment of these brain tumors in young children may include surgery, radiation therapy to the brain and spinal cord and chemotherapy. Radiation therapy is the use of high energy x-rays to kill cancer cells. Chemotherapy means treatment with cancer killing drugs. This research study will compare two different treatment regimens to see which is better for treating children with this type of brain cancer.

In this study we are seeking to learn how different eye tests and devices can help understand vision in patients with NF1, including how vision loss might show up on different eye imaging devices that measure the nerves or the blood vessels of the eye. The study aims to understand the mechanisms of vision loss caused by neurofibromatosis type 1 (NF1)-associated optic pathway gliomas, or NF1-OPGs. Subjects eight years and older with NF1 are eligible to enroll.
Subjects may not benefit directly from participating in this study, but the knowledge gained will help doctors understand the potential benefit of using these tests and other procedures to improve their ability to identify the best tests to monitor visual function, and ultimately identify treatments to improve vision, in children and adults with NF1.

The goal of this observational study is to describe the safety and effectiveness of larotrectinib in patients with locally advanced or metastatic TRK fusion cancer for whom a decision to treat with larotrectinib has been made before enrollment. This study will enroll participants with any tumors harboring the NTRK gene fusion including Soft Tissue Sarcomas, Central Nervous System, Melanoma, and Thyroid cancers.

Children and adults with PTEN Hamartoma Tumor Syndrome (PHTS) are at risk for specific long-term medical complications including autism spectrum disorder and cancer. While protocols for cancer screening exist, we do not yet have protocols for screening other complications of this syndrome, including neurobehavioral differences and immunologic changes. This pilot study will assess these outcomes in children and young adults with PHTS ages 1 to 20 years.

The purpose of this study is to see if a new investigational topical (applied to the skin) formulation of sirolimus, PTX-022 (the study drug), is safe and effective in treating participants with microcystic Lymphatic Malformations.