The presence of leukocytosis associated with non-hematological malignancy after ruling out other causes is defined as paraneoplastic leukemoid reaction (PLR). PLR is a rare manifestation of various solid tumors. It is associated with poor prognosis unless receiving effective antineoplastic treatments. Case Report: A 72-year-old female was referred to a hematologist/oncologist for the evaluation of leukocytosis with neutrophilia. Initial workup was unremarkable; however, she had progressively worsening leukocytosis with neutrophilia, associated with severe anemia and dysphagia. Computed tomography (CT) scan revealed wall thickening at the gastroesophageal junction (GEJ) and multiple hypodensities of the liver. Esophagogastroduodenoscopy (EGD) confirmed the diagnosis of GEJ tumor and biopsy returned as adenocarcinoma with human epidermal growth factor receptor 2 (HER2) overexpression. Leukocytosis resolved after the first round of chemotherapy and the patient remains progression-free with the addition of trastuzumab to her chemotherapy regimen. Conclusions: We report a rare case of PLR caused by GEJ adenocarcinoma. This is the first case of PLR in a patient with metastatic GEJ adenocarcinoma with HER2 overexpression in the Caucasian population. It is important to workup leukocytosis promptly, to keep malignancy in the differential diagnosis and to seek early hematology/oncology consultation.

e21572 Background: Anorectal melanoma is a rare but aggressive type of melanoma, arising primarily from the mucosal epithelium from the anorectal tract. Knowledge of this rare etiology has been limited given its low incidence. This study aims to characterize the epidemiology and treatment outcomes of anorectal melanoma using a national database. Methods: The Surveillance, Epidemiology and End Results (SEER) Database was queried to identify patients with biopsy-proven anorectal melanoma. The following information was retrieved: tumor site, grade, stage, intervention, lymph node histology, and survival information for oncology codes as per the international classification of diseases. Statistical analysis was performed with Stata 15.1 (STATA Corp., College Station, TX, USA). Results: The age-adjusted anorectal melanoma annual incidence rates have been stable approximately 0.4-0.5 per 1 million from 2000 to 2019. Of the 823 biopsy-proven confirmed cases of anorectal melanoma from 2000 to 2018, 150 (18.2%) received chemotherapy, 182 (22.1%) received radiotherapy, 55 (6.7%) received chemoradiation, while 619 (75.2%) of the population received surgery alone or combined with chemotherapy and/or radiotherapy. Statistically significant improvement in survival was noted in treatment strategies that utilized surgery with and without chemotherapy and/or radiotherapy (median survival time 22 vs 9 months, p < 0.0001). Patients with positive regional lymph nodes on pathology were associated with worse prognosis (median survival time 15 vs 37 months, p < 0.0001). Outcomes did not differ based on sex (p = 0.810) and race (p = 0.372). Conclusions: Incidence of anorectal melanoma in the United States has been stable in the last twenty years. Treatment strategies including surgical resection should be adopted if possible to achieve improved survival outcomes.

e16182 Background: Intrahepatic cholangiocarcinoma (iCCA) is a primary hepatic malignancy arising from peripheral intrahepatic bile ducts with poor survival and increasing incidence. Treatment regimen has changed in the last two decades, whereas new molecular targeted therapies have emerged. The present study aims to characterize changes in treatment outcomes of iCCA using a national representative database. Methods: Data were retrieved from the Surveillance, Epidemiology and End Results (SEER) 18 Research Plus Database. Overall survival (OS) was analyzed based on age, gender, race, histological grade, stage, and treatment. Predictors of OS were evaluated by Cox regression models. Statistical analysis was performed with Stata 15.1 (STATA Corp., College Station, TX, USA). Results: The overall observed OS from 2000 to 2018 at 12, 36, and 60 months were 42.6%, 16.4%, and 10.2%, respectively. The median survival time (MST) increased from 6 to 11 months from 2000-2004 time period to 2015-2018 (p < 0.0001). Such an improved trend was observed in all stage groups (p < 0.0001). Among patients diagnosed after 2015, the 12, 24, and 36 month OS were 45.9%, 26.4% and 17.4 %, respectively; the MST were 25, 13, and 6 months for patients with localized (12-month OS: 72.7%; 36-month OS: 37.5% ), regional (12-month OS: 51.4%; 36-month OS: 18.9%), and distant diseases(12-month OS: 28.2%; 36-month OS: 4.5%), respectively (p < 0.0001). On multivariable analysis, older age, female, grade, stage, whether surgery, chemotherapy or radiotherapy was performed were statistically significant predictors of OS (p < 0.001). Conclusions: Survival outcomes of iCCA improved in the last twenty years in all cancer stages. Age, gender, grade, stage, and whether interventions were performed were prognostic factors.