SESSION TITLE: Monday Fellow Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: The occurrence of multiple primary cancers (MPCs) is rare. The diagnosis and treatment of MPCs is often challenging, and often, they cannot be treated simultaneously (1). We report a case of a patient with recurrent pre-B-cell acute lymphoblastic leukemia (pBALL) who was diagnosed with a new non-small cell lung carcinoma (NSCLC). CASE PRESENTATION: A 51 year old male with a remote history of testicular cancer s/p orchiectomy and cisplatin and recurrent pBALL presented with a 4 day history of shortness of breath, non-productive cough and fatigue. Twelve months prior, he was diagnosed with pBALL and treated with 1 cycle of cytarabine, dexamethasone, vincristine, daunorubicin, pegasparagasen and intrathecal methotrexate, and 4 cycles of cyclophosphamide, vincristine, doxorubicin, and dexamethasone, which he completed 2 months prior to presentation. A CT angiogram showed a 2.4 cm right parahilar mass (Figure 1). Bronchoscopy revealed an endobronchial lesion in the right upper lobe (Figure 2) and fine needle aspiration was performed. Endobronchial ultrasound was employed to perform transbronchial fine needle aspiration of station 11R (Figure 2). Immunohistochemistry showed positive staining for CK5/6 and CKAE1/3. P53 staining was also strongly positive in the malignant cells (Figure 3). These staining patterns supported a diagnosis of NSCLC. The patient was readmitted shortly after with recurrence of his pBALL. Unfortunately, given disease progression on imaging and by symptoms, the patient opted for hospice care. DISCUSSION: The prevalence of MPCs is uncertain, ranging between 0.734-11.7%(2). While MPCs are uncommon in general, the combination of hematologic and solid cancers is rare. The SEER database suggests a slight increased occurrence of lung cancer in patients with ALL compared to the general population (3). The etiology is not clear. The few cases that have been published highlight the association between hematologic cancers treated with various chemotherapy regimens and the development of subsequent solid tumors, or a possible hereditary component (1,3). CONCLUSIONS: Although it may seem redundant to biopsy a new lesion identified in a patient with malignancy, it is important that clinicians consider the possibility of MPCs in certain clinical contexts as they can complicate primary disease treatment and may limit treatment options of the new disease. Reference #1: Cui Y, Liu T, Zhou Y, et al. “Five cases report of solid tumor synchronously with hematologic malignancy.” Cancer Res Treat. 2012 Mar;44(1):63-8. https://doi.org/10.4143/crt.2012.44.1.63. Epub 2012 Mar 31. Reference #2: Demandante CG, Troyer DA, Miles TP. “Multiple primary malignant neoplasms: case report and a comprehensive review of the literature.” Am J Clin Oncol. 2003 Feb;26(1):79-83. Review. Reference #3: Shah, B. K. (2013). Second Primary Malignancies In Adult Acute Lymphoblastic Leukemia. Blood, 122(21), 3871. Accessed March 14, 2019. Retrieved from http://www.bloodjournal.org/content/122/21/3871. DISCLOSURES: No relevant relationships by Erum Arain, source=Web Response No relevant relationships by Amit Goyal, source=Web Response No relevant relationships by Michal Reid, source=Web Response