Unusual or unexpected effect of treatment Background:Radiotherapy is often used as an adjuvant therapy in breast cancer following surgical resection of the primary malignant tumor. It has multiple respiratory side effects, but acute respiratory distress syndrome (ARDS) is a rare complication. We describe here the case of a woman with breast cancer who developed ARDS 1 week after her final radiotherapy session. Case Report:A 69-year-old female with breast cancer presented 1 week after her final session of radiotherapy. She had developed a sudden onset of hypotension unresponsive to fluids, oxygen desaturation unresponsive to high flow oxygen, and new bilateral infiltrates had appeared on chest x-ray (CXR) predominant in the left upper lobe, which was interestingly the main area affected by the radiotherapy beams. A diagnosis of atypical ARDS secondary to radiotherapy was established. She was intubated and a low tidal volume/high positive end-expiratory pressure (PEEP) strategy was utilized to manage her condition. After 48 hours, the infiltrates diminished remarkably, and she was extubated the following day. On discharge, she had a completely normal CXR; a computed tomography (CT) chest performed 1 month later showed complete resolution of the alveolar opacities. Conclusions:ARDS remains an extremely rare complication of thoracic radiotherapy. However, physicians must be wary of its development in order to diagnose it quickly and treat accordingly.

Background: Cytomegalovirus (CMV) infections are common, especially in immunocompromised patients. These infections are usually asymptomatic but can become symptomatic in immunocompromised individuals, with colitis being the second most common presentation of end-organ disease. CMV colitis can mimic Inflammatory Bowel Disease (IBD) or cause an IBD flare, thus making the diagnosis challenging. Case Report: We describe the case of a 69-year-old male known to have Chronic Lymphocytic Leukemia (CLL) maintained in remission on venetoclax, a BCL-2 inhibitor. The patient was recently started on mesalamine and steroids after a Crohn’s Disease (CD) diagnosis three weeks before presentation. The patient presented with bloody diarrhea and abdominal pain. His workup included a colonoscopy that showed skip lesions (diffuse ulcerated lesions separated by areas of normal mucosa), a characteristic of CD. Ileal and colonic biopsies were sent for Polymerase Chain Reaction (PCR) of CMV and turned out positive. Therefore, the patient was diagnosed with CD with superimposed CMV colitis. We started the patient on ganciclovir. Three months later, a repeat colonoscopy revealed complete resolution of mucosal ulcerations, practically changing the diagnosis to an isolated CMV colitis mimicking CD. Conclusion: An isolated CMV colitis can mimic CD, and physicians must consider this entity in their differential diagnosis. This case is additionally remarkable because CLL and the use of a BCL-2 inhibitor usually have a protective role against CMV disease, but this was not the case for our patient.