LAUSR

An asymptomatic 54-year-old Samoan woman with metastatic, anaplastic lymphoma kinase (ALK)-positive, poorly differentiated, non-small cell lung cancer was asymptomatically found to have an incidental large volume intraperitoneal free gas with a continuous diaphragm sign on routine surveillance chest X-ray (Fig. 1). The radiograph was obtained six months after treatment commencement with Alectinib (an ALK inhibitor) to which the patient had had an excellent response. She was acutely admitted to a general surgery unit where a subsequent computed tomography scan confirmed the large pneumoperitoneum and revealed intra-abdominal features consistent with pneumatosis cystoides intestinalis (PCI) (Fig. 2). Her initial management included ceasing Alectinib, and prophylactic antibiotic cover. Follow-up cross-sectional imaging showed persisting free gas within the peritoneal cavity, and bubbles widely scattered (with the largest inter-loop gas and fluid collection complex measuring 6 7 10 cm). Due to concerns about continuing Alectinib, the patient opted to take a break; however, 2 months after ceasing treatment imaging showed progressive disease, at which point Alectinib was recommenced, without reoccurrence of PCI thus far.