Progressive calcification in a solitary pulmonary nodule: a 7-year follow-up revealing primary pulmonary amyloidosis

Solitary nodular pulmonary amyloidosis is a rare benign condition that is most often detected incidentally during routine health examinations. Although calcification within the nodule is a well-recognised characteristic finding, there are few reports that document its chronological progression. We describe the case of a man in his 70s with an incidentally identified solitary pulmonary nodule in the right lower lobe, which was followed for more than 7 years from the initial detection. During this period, the calcification advanced from partial involvement to diffuse distribution throughout the nodule, in parallel with nodule enlargement. This case demonstrates that calcification in nodular pulmonary amyloidosis represents a dynamic process reflecting long-term amyloid deposition and associated subtle tissue alterations, rather than a static lesion. Furthermore, it highlights that temporal changes in calcification density may provide important diagnostic clues.