Diagnosing pulmonary MALT lymphoma: a case of unilateral cystic lesions.

We present an atypical case of a 62-year-old female diagnosed with pulmonary mucosa-associated lymphoid tissue (p-MALT) lymphoma, which uniquely manifested as a singular cystic lesion in the lung. Diagnostic evaluations, including comprehensive imaging, bronchoscopy, and CT-guided lung biopsy, revealed this uncommon radiological presentation. Detailed histopathological and immunohistochemical assessments further supported the diagnosis. To determine the extent of the disease, systemic evaluations, such as whole-body PET-CT, gastroscopy, colonoscopy, and bone marrow biopsy, were conducted, confirming its localized nature. Following the definitive diagnosis, the patient underwent a rituximab-centric therapeutic regimen, which yielded significant clinical improvement. This case highlights the importance of recognizing distinctive cystic lung features in p-MALT lymphoma and the indispensable role of holistic diagnostic approaches in guiding precise therapeutic and prognostic decisions.