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- pulmonary lymphoma
- mucosa-associated lymphoid tissue (MALT)
- bronchial-associated lymphoid tissue
- MALT lymphoma
- Sjrogren’s syndrome
Clinical presentation
A 64-year-old woman presented to our hospital complaining of generalised fatigue and history of mechanical fall with rib fractures while in Africa. Chest X-ray (CXR) incidentally discovered multiple bilateral pulmonary nodules. She has a history of rheumatoid arthritis on methotrexate, Hashimoto’s thyroiditis, Sjögren’s syndrome (SS) and psoriatic arthritis on immunotherapy. She denied symptoms of cough, chest pain, dyspnoea, weight loss, night sweats, fever or haemoptysis. She denied smoking, alcohol consumption, illicit drug use and environmental exposures. She had a family history of lymphoma in sister but no personal/family history of arteriovenous malformations, hamartomas or vasculitis. CXR conducted 3 years prior showed no lesions. She was up-to-date with breast screening but refused colonoscopy. Physical exam was unremarkable.
On arrival to USA, chest CT confirmed bilateral nodules with lower lung predominance (figure 1) and positron emission tomography scan demonstrated hypermetabolic activity of the nodules. Lab work—blood count, metabolic profile, urinalysis, immunoglobulins, HIV, serum/urine protein electrophoresis and vasculitis panel—was normal. Infectious workup—for tuberculosis, histoplasmosis, coccidiomycosis, pneumocystis, and bacterial and viral pneumonia—were also negative. She was positive for SS-A and SS-B antibodies, negative for rheumatoid factor, anti-Scl-70 and anti-Jo-1 antibodies, and had normal antinuclear antibodies. Bone marrow biopsy and flow cytometry were normal. She underwent bronchoscopic transbronchial biopsy of nodules and endobronchial ultrasound-guided transbronchial needle aspiration of lymphadenopathy; these were non-diagnostic. Then, the patient underwent CT-guided biopsy, which showed dense lymphoplasmacytic inflammatory infiltration but was negative for malignancy. Finally, surgical thoracoscopy was performed with wedge resection.
Chest CT, axial view (A) and coronal view (B). Bilateral, multiple pulmonary nodules with random distribution, varying sizes and smooth contours. Anterior left upper lung nodule shows surrounding ground-glass changes. Lesions are not distributed in any particular pattern, that is, not following lymphatics or vasculature. Microscopy: ×40 magnification, H&E staining (C). Dense, monotonous population of centrocyte-like cells with plasmacytoid differentiation, with residual germinal centres and lymphoepithelial lesions. Microscopy with ×40 magnification, CD20+ immunohistochemical staining (D), highlights the extensive B-cell infiltration.
Question
What is the diagnosis?
Answer
This patient, with a significant history of autoimmune disease, underwent wedge resection—pathology showed mucosa-associated lymphoid tissue (MALT) lymphoma of the lung. MALT lymphoma is a rare, indolent, extranodal lymphoma constituting 0.5% of primary lung neoplasms. While MALT lymphoma most commonly occurs in the gastrointestinal tract in association with Helicobacter pylori infections, other potential origins are salivary glands, orbits, thyroid and lungs.1 The suspected pathogenesis is chronic antigenic stimulation of lymphoid tissue by infection, inflammation and autoimmune stimuli. The most common gene defect is translocation t(11;18)/BIRC3-MALT1 with activation of NF-ĸB pathway triggering neoplastic transformation. Among the autoimmune disorders, SS is most strongly associated with the development of MALT lymphoma. Interestingly, Achromobacter xylosoxidans has been linked to pulmonary MALT lymphomas. The disease has no specific signs and symptoms; 36% of patients are asymptomatic at diagnosis.2
Radiographic imaging shows variable presentation.3 Diagnosis requires a surgical biopsy, usually wedge resection, during video-assisted thoracoscopy or thoracotomy, as the yield from bronchoscopic transbronchial and CT-guided biopsies is very low.4 Immunohistochemical staining is crucial to assess the architecture of the lymphoid infiltrate and to exclude other lymphomas.1 Pulmonary MALT lymphoma has an excellent 5-year overall survival rate (>80%). Optimal management is controversial due to the lack of evidence-based guidelines. Patients with systemic disease (stage III/IV—Ann Arbor Classification) receive a chemotherapeutic agent (bendamustine, fludarabine or chlorambucil) combined with anti-CD20 antibody (rituximab).5 Our patient received bendamustine and rituximab therapy due to the progression of her lymphoma; 3 months later, she is making a remarkable recovery and shows radiographic improvement.
Footnotes
Contributors SP, the principal author, made substantial contributions to study conception and design, acquisition, analysis and interpretation of data, and drafting and final revision of the manuscript. WN, the second author, made contributions by reviewing imaging, sources and references, helping to acquire patient consent and reviewing drafts for multiple revisions for flow, organisation and tone. RK, the third author, made significant contributions to drafting and final revision of the manuscript for important intellectual content. LH, the fourth author, made contributions by revising the initial manuscript drafts and making final revisions on word selection and grammar.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Disclaimer All of the authors certify our affiliations and have no disclosures to report. We all certify that our affiliations with, or financial involvement with any organisation, or entity with a financial interest in, or financial conflict with the subject matter, or materials discussed in the manuscript are completely disclosed.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; internally peer reviewed.