Perilymphatic micronodular pattern as a manifestation of pulmonary amyloidosis on high-resolution computed tomography

The term amyloidosis describes a group of diseases caused by the fibrillar deposit of poorly folded proteins in tissues with a secondary alteration of their function. Diffuse parenchymal lung disease associated with amyloidosis is rare and is most often diagnosed in autopsy. A 45-year-old male patient presented an acute episode of cough with mucoid expectoration. He had also dyspnea, dry cough, chest pain, and constitutional symptoms of 6 months of evolution. Initially the case was treated as acute pneumonia. After taking radiological images of the thorax, a diagnostic suspicion of lymphangitic spread of neoplasia was assumed. Histopathological findings of an open pulmonary biopsy demonstrated interstitial thickening with perivascular eosinophilic invasion. Congo Red staining and immunohistochemistry studies were done and turned out to be positive for amyloid. The perilymphatic micronodular pattern as a radiological manifestation of parenchymal pulmonary amyloidosis has been very rarely described in the literature, therefore it must be considered as a differential diagnosis in patients with this pattern in CT scan and should be an incentive for its histopathological study once a neoplasm is ruled out.