Pre-reinductive Decitabine and Vorinostat in Relapsed Lymphoblastic Lymphoma or Acute Lymphoblastic Leukemia

Inclusion Criteria: * Diagnosis of lymphoblastic lymphoma or acute lymphoblastic leukemia with ≥ 5% blasts in the bone marrow (M2/M3) (with or without extramedullary disease) that meets 1 of the following criteria: * Refractory disease/induction failure (failure to achieve initial remission after 2 lines of induction therapy) * Relapsed disease (in first relapse or higher) * Central nervous system (CNS)-positive disease allowed * Karnofsky performance status (PS) 50-100% (for patients ≥ 16 years of age) OR Lansky PS 50-100% (for patients \< 16 years of age) * Life expectancy ≥ 8 weeks * Creatinine clearance ≥ 70 mL/min OR maximum serum creatinine based on age/gender as follows: * 0.4 mg/dL (for patients 1 to 5 months of age) * 0.5 mg/dL (for patients 6 to 11 months of age) * 0.6 mg/dL (for patients 1 year of age) * 0.8 mg/dL (for patients 2 to 5 years of age) * 1.0 mg/dL (for patients 6 to 9 years of age) * 1.2 mg/dL (for patients 10 to 12 years of age) * 1.5 mg/dL (males) or 1.4 mg/dL (females) (for patients 13 to 15 years of age) * 1.7 mg/dL (males) or 1.4 mg/dL (females) (for patients ≥ 16 years of age) * ALT \< 5 times upper limit of normal (ULN) * Total bilirubin ≤ 1.5 times ULN for age * LVEF ≥ 40% by ECHO/MUGA scan * Shortening fraction \> 29% by ECHO/MUGA scan * Able to swallow capsules * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 2 months after completion of study treatment * No untreated positive blood cultures or progressive infections as assessed by radiographic studies * No known allergy to any of the agents or their ingredients used in this study * Patients with clinically significant prior allergies to pegaspargase may be treated with asparaginase-Erwinia, if available * Patients who cannot receive asparaginase on this study (e.g., due to prior pancreatitis, stroke, or other toxicity) are eligible provided they meet all other inclusion/exclusion criteria * Recovered from prior therapy (defined as CTCAE v3.0 toxicity ≤ grade 1) * More than 3 weeks since prior chemotherapy for cancer other than hydroxyurea for patients with WBC \> 10,000/mm³ * At least 7 days since prior hematopoietic growth factors (14 days for pegfilgrastim) * At least 1 month since prior biologic therapy, such as monoclonal antibodies * At least 3 months since prior hematopoietic stem cell transplantation Exclusion Criteria: * Evidence of graft-versus-host disease * Concurrent valproic acid * Concurrent coumadin/warfarin other than a short course administered in a prophylactic setting