Patient description: A 17 year old boy complains of vomiting, non-bloody diarrhea, abdominal pain, fever, chills and loss of appetite for the past 3 days. He ate a salad at a restaurant prior to his diarrhea onset. Physical exam was remarkable for pallor, jaundice, and diffuse abdominal tenderness. Lab results were as follows: Hemoglobin: 9.7 g/dL Platelet: 110,000 /cu.mm Creatinine: 3.6 mg/dL blood urea nitrogen (BUN): 73 mg/dL direct bilirubin: 2.4 mg/dL lactate dehydrogenase (LDH): 881 IU/L (normal: 110-265 IU/L) Peripheral blood smear showed a moderate number of schistocytes and helmet cells. Shiga-like toxin-producing E. coli (STEC) stx1/stx2 were found in stools. He has no other underlying disease and he is not on any medications.

Clinical trial eligibility criteria: eligible ages (years): 1.0-21.0,  Central Nervous System Embryonal Tumor With Rhabdoid Features Central Nervous System Embryonal Tumor, Not Otherwise Specified Central Nervous System Ganglioneuroblastoma Embryonal Tumor With Multilayered Rosettes, C19MC-Altered Pineoblastoma Primary Central Nervous System Neoplasm Recurrent Childhood Central Nervous System Embryonal Neoplasm Recurrent Malignant Solid Neoplasm Recurrent Medulloblastoma Recurrent Neuroblastoma Recurrent Rhabdomyosarcoma Refractory Malignant Solid Neoplasm Refractory Medulloblastoma Refractory Neuroblastoma Refractory Rhabdomyosarcoma Patients must have had histologic verification of malignancy at original diagnosis or relapse except in patients with intrinsic brain stem tumors, optic pathway gliomas, or patients with pineal tumors and elevations of cerebrospinal fluid (CSF) or serum tumor markers including alpha-fetoprotein or beta-human chorionic gonadotropin (HCG) Part A: Patients with relapsed or refractory solid tumors, including patients with primary or metastatic CNS tumors Part B: Patients with relapsed or refractory neuroblastoma Part C: Patients with relapsed or refractory medulloblastoma or CNS embryonal tumors formally classified as PNET (pineoblastoma, CNS neuroblastoma, CNS ganglioneuroblastoma, embryonal tumor with multi-layered rosettes, medulloepithelioma, CNS embryonal tumor with rhabdoid features [INI1 intact] and CNS embryonal tumor, not otherwise specified) Part D: Patients with relapsed or refractory rhabdomyosarcoma Part A: Patients must have a body surface area >= 0.35 m^2 at the time of study enrollment if enrolling on dose levels 1-5; patients must have a body surface area >= 0.46 m^2 at the time of study enrollment if enrolling on dose level 0 Parts B, C, and D: Phase 2 Expansion: Patients must have a body surface area of > 0.49 m^2 at the time of study enrollment at the recommended phase 2 dose of AZD-1775 Part A: Patients must have either measurable or evaluable disease Part B: Patients must have either measurable disease or must be evaluable for MIBG response without evidence of Response Evaluation in Solid Tumors (RECIST) measurable lesions; patients with neuroblastoma in bone marrow only are not eligible Part C: Patients must have measurable disease by computed tomography (CT) or magnetic resonance imaging (MRI)  Pregnant or breast-feeding women may not be entered on this study as there is yet no available information regarding human fetal or teratogenic toxicities; pregnancy tests must be obtained in girls who are post-menarchal Males or females of reproductive potential may not participate unless they have agreed to use an effective double barrier contraceptive method for the entire duration of protocol therapy and for 3 months (males) and 1 month (females) after study drug discontinuation Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible Patients who are currently receiving another investigational drug are not eligible Patients who are currently receiving other anti-cancer agents are not eligible Patients who are currently receiving drugs that are strong or moderate inhibitors and/or inducers of cytochrome P450, family 3, subfamily A, polypeptide 4 (CYP3A4) or sensitive CYP3A4 substrates and CYP3A4 substrates with a narrow therapeutic range are not eligible; the use of aprepitant as an antiemetic is prohibited due to early drug interaction data demonstrating increased exposure to AZD1775 (MK-1775); caution should be exercised with concomitant administration of AZD1755 (MK-1775) and agents that are sensitive substrates of cytochrome P450, family 2, subfamily C, polypeptide 8 (CYP2C8), 2C9 and 2C19, or substrates of this enzyme with narrow therapeutic ranges, as well as agents that are inhibitors or substrates of permeability glycoprotein (P-gp) Patients who are receiving cyclosporine, tacrolimus or other agents to prevent graft-versus-host disease post bone marrow transplant are not eligible for this trial Patients must not have received enzyme inducing anticonvulsants for at least 14 days prior to enrollment Patients with cardiac diseases ongoing or in the past 6 months (e.g. congestive heart failure, acute myocardial infarction, significant uncontrolled arrhythmias) are not eligible for this trial Patients who have an uncontrolled infection are not eligible