What does this research mean for the field?

Nodular pulmonary amyloidosis is a rare condition that can present as asymptomatic, waxing and waning lung nodules mimicking malignancy, requiring tissue biopsy with Congo Red staining for definitive diagnosis. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This case explores the presentation and challenges of diagnosing nodular pulmonary amyloidosis.

May 20, 2026

A40-03 Nodular Nonsense - Atypical Presentation of Pulmonary Amyloidosis

Key Points

This case explores the presentation and challenges of diagnosing nodular pulmonary amyloidosis.
Case presentation of a 67-year-old male with asymptomatic lung nodules.
CT guided core biopsy and staining were used for diagnosis.
Exclusion of plasma cell disorders and MALT lymphoma via various tests.
CT imaging showed apically predominant lung nodules with a significant enlargement.
Biopsy results indicated AL-type amyloid deposition with characteristic Congo Red staining.
Localized cases typically exhibit excellent prognosis and are monitored conservatively.

Abstract

Abstract Background Amyloidosis is characterized by abnormal protein conformational changes and subsequent deposition resulting in organ dysfunction. Pulmonary amyloidosis, whether as part of a systemic disease or localized, is most associated with AL (immunoglobulin light chain) subtype. We present a case of nodular pulmonary amyloidosis a rare cause of pulmonary nodules. Case Presentation A sixty-seven-year-old Caucasian male presented to the pulmonary clinic for asymptomatic lung nodules. He was a former smoker and had retired from a coal fired energy plant. Lung cancer screening CTs showed waxing and waning apically predominant lung nodules with a dominant and enlarging nodule in the left lower lobe. A CT guided core biopsy of this lesion demonstrated salmon pink coloration on Congo Red stain and apple green birefringence under polarized light consistent with nodular pulmonary amyloidosis. LC MS confirmed AL - type amyloid deposition. SPEP/UPEP, SIFE, flow cytometry, and serum free light chains did not reveal a plasma cell disorder. CT abdomen/pelvis was negative for signs of occult extra-nodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). Discussion Nodular pulmonary amyloidosis is one of four distinct histopathological types of amyloidosis affecting the respiratory system. It is often diagnosed incidentally, or in association with MALT lymphoma or systemic connect tissue disease. It is typically comprised of AL-type amyloid deposition. Diagnosis can prove difficult given patients are often asymptomatic, but CT findings include peripheral and subpleural nodules most commonly residing in the lower lobes. Over time they may grow and cavitate, mimicking other pathologies. FDG PET-CT does not perform well in distinguishing nodular amyloidosis from malignancy. Tissue remains gold standard in diagnosis with Congo Red staining. Treatment varies depending on burden of disease and the presence or absence of systemic involvement. Most cases of localized disease have an excellent prognosis and are managed with radiographic monitoring and occasional conservative excision. This abstract is funded by: none

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