Pulmonary nodules associated with pulmonary embolism: A rare and misleading presentation of amyloidosis

Abstract

Amyloidosis is a rare disease especially the localized form involving pulmonary parenchyma. We report the case of a 74 years old woman who presented with chest pain and dyspnoea. CT scan showed pulmonary embolism and bilateral nodules. Laboratory examinations highlighted circulating Kappa IgM. 18F-FDG PET/CT showed intense activity of the nodules. Histological investigation supported the diagnosis of nodular pulmonary amyloidosis. There were no sign of systemic amyloidosis or autoimmune disease. No treatment was initiated: the patient remains asymptomatic after one year. Localized pulmonary amyloidosis related to MGUS was the most likely diagnosis. Malignancy, a differential diagnosis of pulmonary amyloidosis, must be excluded: histological examinations are overriding. Difference between systemic and localized amyloidosis conditions treatment and prognosis. This observation emphasizes the difficulty to establish the diagnosis of pulmonary nodular amyloidosis and the complex relationship between amyloidosis and thromboembolism.

Keywords: Amyloidosis; MGUS; Monoclonal gammopathy of undetermined significance; Nodular pulmonary amyloidosis; Pulmonary embolism.

Figure 1

Chest CT Scan, parenchymal window showing multiple bilateral nodules.

Fig. 2

Pulmonary amyloidosis. Homogenous eosinophilic amorphous extracellular deposits with standard staining (A: x10 and B: x100). Amyloid deposits on congo red stain (C) with apple green birefringence under polarized light (D).