Isolated Pulmonary Light Chain Deposition Disease

Area of Science:

• Pulmonology
• Rheumatology
• Nephrology

Background:

• Pulmonary involvement is common in autoimmune diseases, presenting as interstitial lung disease, cystic lung disease, pulmonary hypertension, or pleural disease.
• Light-chain deposition disease (LCDD) is a rare manifestation of autoimmune conditions affecting the lungs.
• This case highlights the diagnostic challenges and variability in presentation of pulmonary LCDD.

Purpose of the Study:

• To report a case of pulmonary light-chain deposition disease.
• To emphasize the importance of considering LCDD in patients with autoimmune diseases and unexplained lung findings.
• To discuss the diagnostic and management considerations for this rare condition.

Main Methods:

• A case report of a 55-year-old female with Sjögren's syndrome and history of thyroid cancer.
• Computed tomography (CT) and positron emission tomography/CT (PET/CT) imaging were used for surveillance and assessment of pulmonary nodules and cysts.
• Lung biopsy was performed for definitive diagnosis.

Main Results:

• Imaging revealed progressive pulmonary nodules and large pneumatoceles.
• Lung biopsy confirmed monotypic kappa light-chain deposition with plasma cell infiltration, diagnosing LCDD.
• The patient remained asymptomatic despite radiographic progression and was managed conservatively.

Conclusions:

• Pulmonary LCDD is a rare, under-recognized condition requiring high clinical suspicion.
• Imaging findings like cystic lung disease and nodules warrant consideration of LCDD, particularly in autoimmune disease patients.
• Biopsy is essential for diagnosis, and management is individualized due to lack of guidelines.