Here, we present a 76-year-old woman, who presented to the hospital with flank pain due to a complicated UTI in December of 2018. The patient had a past medical history of psoriatic arthritis, two prior TIAs, hysterectomy, diverticulitis, and a neck injury in a road traffic accident. As part of the investigations for the UTI, a CT thorax abdomen pelvis was performed which revealed a 2.4 cm rounded pulmonary ground glass opacity (GGO) in the right middle lobe (a). In January of 2019, the patient underwent a CT-guided core biopsy of the lung which demonstrated a dense chronic inflammatory infiltrate, including lymphocytes and plasma cells (a, b). Lymphoepithelial lesions were not identified. The lymphoid population was B cell predominant (CD20+). The B cells were negative for CD5, CD10, CD23, and cyclin D1. Ki67 was low (<20%). Definitive light chain restriction was not demonstrated by immunohistochemistry but multiplex PCR confirmed a clonal B cell population (clonal immunoglobulin heavy chain gene rearrangements VFR1-J, VFR2-J, and VFR3-J) (c, d). The morphology, immunophenotype, and molecular genetic information were consistent with a diagnosis of stage 1 low – grade B cell non-Hodgkin’s lymphoma of mucosa-associated lymphoid tissue MALT type. The patient also underwent a bone marrow biopsy in March of 2019 and the bone marrow was found to be mildly hypercellular with increased megakaryocytes but no evidence of marrow involvement by lymphoma. The patient was treated with 4 cycles of rituximab starting on the April 30, 2019 with the last cycle being administered on the 21st of May. A repeat CT thorax was done in July that same year and the GGO was found to be stable in size (b). During a follow-up positron emission tomography (PET)-CT scan in September 2019, the GGO was found to have increased slightly in size from 16 × 17 × 22 mm to 19 × 28 × 17 mm with low level FDG uptake and a maximum SUV of 2.6 (d), however no new pulmonary or pleural lesions were identified (c). The patient was then treated with radiotherapy during January and February of 2021 with a total of 30 Gy delivered in 15 fractions. The patient tolerated the treatment well and no significant toxicities or side effects were reported. After therapy, the patient has had a series of CT scans which have shown no new abnormalities. The radiological abnormality in the treatment site has remained stable, as seen in a follow-up CT-TAP performed in May 2021, with maximal axial dimensions having reduced from 24 mm to 15 mm at the corresponding level (). And follow-up CT scans in May of 2022 and May of 2023 showed stability in size. As this represents 2 years and 3 months of follow-up, we can assume that the disease is controlled.