Inherited thrombocytopenia is a topic that was expanded greatly over the last decade and many new genes are being identified. However, inheritance patterns are not always easy to identify because sporadic cases from de novo mutations may in fact be more common. Few studies have assessed the relationship between thrombocytopenia and malignancies, specifically acute lymphoblastic leukemia (ALL). Here we present a pediatric case of persistent thrombocytopenia associated with T-cell ALL. Our patient was initially diagnosed with immune thrombocytopenic purpura with no evidence of malignancy on bone marrow biopsy but presented shortly after with ALL.