Appendiceal neoplasms are uncommon; most are identified by pathologic examination after appendectomy for presumed appendicitis or as an incidental finding. When found incidentally, patients are typically asymptomatic. If the neoplasm has perforated, patients may present with symptoms that mimic acute appendicitis. In advanced disease, patients may have systemic symptoms associated with peritoneal disease, including abdominal distension, weight loss, and diffuse abdominal pain. Because of their rarity, as well as rapidly evolving research on the subject, the nomenclature of appendiceal mucinous neoplasms has proven challenging. This lesion was identified as a low-grade appendiceal mucinous neoplasm (LAMN), previously termed mucoceles or mucinous cystadenomas. LAMNs are non-invasive neoplasms that have the potential to proliferate outside the appendix in a malignant fashion. All mucinous appendiceal neoplasms can perforate and spread mucin production throughout the abdominal cavity, known as pseudomyxoma peritonei (PMP). The presence of PMP designates LAMNs as malignant, though the neoplasm itself is non-invasive. When appendiceal neoplasms have peritoneal involvement, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is the standard of care. Complete cytoreduction has been shown to be an independent predictor of survival. Here we describe a case of a 30-year-old male involved in a motor vehicle collision with a grade IV splenic laceration, who is also found to have a large appendiceal mass. His traumatic injuries required emergent intervention, which delayed treatment of his malignancy.