# Pulmonary Mucosa‐Associated Lymphoid Tissue (MALT) Lymphoma: A Diagnostic Dilemma

## TL;DR

This case report discusses a rare lung lymphoma in a patient with lupus, highlighting diagnostic challenges and mixed treatment responses.

## Contribution

The report adds to the limited literature on pulmonary MALT lymphoma, emphasizing its diagnostic difficulty and variable treatment outcomes.

## Key findings

- Pulmonary MALT lymphoma was diagnosed incidentally in a patient with systemic lupus erythematosus.
- Rituximab therapy showed only a mild radiographic response despite clinical stability.
- The case underscores the need for further research on optimal treatment strategies for this rare lymphoma.

## Abstract

Primary pulmonary lymphoma (PPL) is a rare clonal proliferation of lymphoid tissue confined to the lungs, representing only 0.5%–1% of all lung neoplasms. Pulmonary mucosa‐associated lymphoid tissue (MALT) lymphoma is the most common subtype and is often associated with chronic inflammation and autoimmune conditions. Diagnosis is challenging given its indolent course, nonspecific clinical features and variable radiographic presentations. We report a 64‐year‐old female with systemic lupus erythematosus who was incidentally found to have multiple pulmonary nodules. Serial imaging revealed interval growth and biopsy confirmed pulmonary MALT lymphoma. A watchful waiting strategy was initially employed, but subsequent disease progression prompted rituximab therapy, with only mild radiographic response despite preserved clinical stability. This case highlights the diagnostic challenges of pulmonary MALT lymphoma, the variability in treatment response and the potential interplay with autoimmune disease. Further studies are needed to clarify optimal therapeutic approaches, including the role of macrolides and autoimmune‐directed therapies.

This case report describes a patient with systemic lupus erythematosus who was incidentally diagnosed with pulmonary MALT lymphoma after years of indolent radiographic progression. Management included a prolonged period of observation followed by rituximab, with only a partial radiographic response. The case emphasises the diagnostic challenges and variable treatment outcomes of this rare lymphoma.