266 Single Symptomatic Ileal Metastasis as First Presentation of Pulmonary Mucoepidermoid Carcinoma

Introduction/Objective Mucoepidermoid carcinoma (MEC) is a rare malignant tumor, that mostly arises from the salivary glands, lungs and pancreas. It is frequently associated with MAML2 rearrangement, but TP53 mutations demonstrate aggressive phenotypes. MEC accounts for 0.1-0.2% of primary pulmonary tumors. The most common sites of metastasis are lung, bone and liver. Metastasis to the gastrointestinal tract is extremely rare. Methods/Case Report We report a case of a 58-year-old male who presented with clinical features of small bowel obstruction. Emergent right hemicolectomy revealed a white, mucoid, well-demarcated mass in ileal wall with serosal adhesion, sparing the overlying mucosa. Histologic sections revealed glands with inner mucinous cells staining for EMA and outer epidermoid cells staining for p40 and p63. Overall, these features are most compatible with MEC. TP53 frameshift mutation was detected. On further evaluation, imaging revealed a right middle lobe lung mass; however, the initial biopsy was inconclusive. Unfortunately, despite chemotherapy, the patient passed away 7 months later due to widespread metastasis to liver and bones. Results NA Conclusion Recognizing the characteristic morphology of MEC is essential, particularly due to rare occurrence in the respiratory tract. This case highlights the importance of early diagnosis of lung lesions that raise suspicion for malignancy on imaging.