LETTER TO THE EDITOR further evaluation with a bone marrow biopsy or requiring therapeutic intervention. Bone marrow biopsy may not be indicated in patients with SARS-CoV-2 infection and hematological abnormalities given the transient nature of blood cell lines even in those with trisomy 21. ACKNOWLEDGMENTSThe authors would like to acknowledge the multidisciplinary team at Lehigh Valley Reilly Children's Hospital. We would like to acknowledge the child and her family for providing consent for the publication of this report.

Ewing sarcoma is an aggressive malignancy of bone and soft tissue that accounts for approximately 2% of cases of childhood cancer. It has been rarely reported as a secondary neoplasm. Data from the Childhood Cancer Survivor Study has evaluated secondary sarcomas in 5-year survivors of childhood cancer. We report two pediatric patients in northeast Pennsylvania, who developed secondary Ewing Sarcoma of the 9th rib within 5 years of primary childhood leukemia diagnoses.

Ewing sarcoma is an aggressive malignancy of bone and soft tissue that accounts for ∼2% of cases of childhood cancer. It has been rarely reported as a secondary neoplasm. Data from the Childhood Cancer Survivor Study has evaluated secondary sarcomas in 5-year survivors of childhood cancer. We report 2 pediatric patients in northeast Pennsylvania, who developed secondary Ewing sarcoma of the 9th rib within 5 years of primary childhood leukemia diagnoses.

Background Bloodstream infections (BSIs) remain a significant cause of morbidity and mortality in children with leukemia. They are at an increased risk of infectious complications secondary to intense chemotherapeutic regimens during induction resulting in prolonged and profound neutropenia. To our knowledge, there is limited literature regarding pathogens and antibiotic resistance from smaller institutions similar to ours. The primary objective of this review was to describe the microbiology of BSIs, and second to evaluate our rates of BSIs during induction chemotherapy as compared to larger institutions. Method Retrospective chart review of 82 eligible patients between the age of 1 and 21 years with newly diagnosed leukemia between May 1, 2010 and May 31, 2020. Patients who did not complete the entirety of induction chemotherapy at our hospital were excluded. A microbiologically documented infection was defined as a causative pathogen isolated from the blood in the setting of fever and/or neutropenia. Neutropenia was defined as an absolute neutrophil count (ANC) of less than 0.5x109 cells/L. Results Of the 82 patients, 12 (14.6%) patients had a BSI during induction chemotherapy. The most common organisms identified were Gram-positive cocci (75%), Gram-negative bacilli (16.6%), and Gram-negative cocci (8.3%). Methicillin-susceptible Staphylococcus aureus (MSSA) was the most frequently isolated organism (42%) overall. No methicillin-resistant Staphylococcus aureus (MRSA) was identified. Of the Gram-negative bacteria isolated, Escherichia coli (8%) and Pseudomonas aeruginosa (8%) were identified. No extended spectrum beta-lactamase (ESBL) or multi-drug resistant organisms were identified. No fungi were isolated. Conclusion The incidence of BSIs in children during induction chemotherapy at our institution is similar to what is reported from larger, academic centers. Gram-positive cocci comprise 75% of BSIs with no MRSA isolates in 10 years. Our antibiogram shows no resistant Gram-negative bacteria. This is in contrast to what is reported to larger pediatric cancer centers. Therefore, current empiric monotherapy with a fourth generation cephalosporin at the onset of febrile neutropenia remains adequate for our pediatric oncology patients.

Introduction: Central retinal vein occlusion (CRVO) is a rare finding in children. Well-known risk factors include hypertension and diabetes in older patients. CRVO has also been attributed to local causes such as compression or inflammation secondary to trauma, as well as systemic causes, such as thrombophilia or hyperviscosity etiologies. Here, we describe a case of recurrent bilateral CRVO in an otherwise healthy child. Design/Methods: This is a retrospective case report reviewing a patient with recurrent bilateral CRVO. Ophthalmological and pediatric records were reviewed. Results: A 10-year-old previously healthy male presented with sudden onset blurry vision of his left eye and was found to have CRVO with venous engorgement of the retina. He had a grandfather with polycythemia vera, but no other contributing family history. Initial coagulopathy workup was normal with a PTT of 29 sec, PT INR of 1.1 sec, fibrinogen of 291 mg/dL, Factor VIII of 174%, Von Willebrand Factor Antigen of 139%, Von Willebrand Factor Activity of 132%, Factor IX of 101%, and Factor XI of 112%. Computed tomography (CT) of the head was unremarkable. At the age of 13, he developed acute onset headache with blurry vision of his right eye. He had evidence of macular edema and CRVO of his right eye. Ophthalmology treated him three injections of vascular endothelial growth factor inhibitor, aflibercept, over four months with improvement in both macular edema and visual acuity. Daily aspirin prophylaxis was also initiated pending further hypercoagulability workup. Laboratory investigation for an inherited or acquired hypercoagulability including prothrombin mutation, AT III mutation, hyperhomocysteinemia, protein C & S, and antiphospholipid were negative. He initially had a positive cryoglobulin found to be negative on repeat evaluation. He underwent a comprehensive rheumatological and infectious workup that was unrevealing. Additionally, he had an elevated RBC of 6.09 mill/cmm, hemoglobin of 18.2 g/dL, and hematocrit of 52.0% but a targeted panel for inherited erythrocytosis and polycythemia was normal. The patient remained symptomatic with persistent episodes of blurred vision and lightheadedness. Further extensive hematologic workup revealed reduced thrombin inhibitor and elevated rates of thrombin formation. Lipoprotein (a) was 168 mg/dL. Interestingly, his mother had elevated rates of thrombin formation and a lipoprotein (a) level of 153 mg/dL. The patient is currently being treated with therapeutic rivaroxaban and whole exome sequencing (WES) for the patient and both parents are pending. Conclusion: This case demonstrates a novel cause of recurrent bilateral CRVO secondary to reduced thrombin inhibition resulting in accelerated rates of thrombin formation and elevated lipoprotein (a) overall supporting a hypercoagulable state. Perhaps, there is a familial component predisposing recurrent thrombosis in this patient. Whole exome sequencing is pending to evaluate for a genetic predisposition to his findings. After completing a full course of therapeutic anticoagulation, he will likely require lifelong prophylaxis to reduce the risk of future thrombotic events and preserve his vision. Disclosures No relevant conflicts of interest to declare.