Pulmonary amyloidosis is found in both systemic and localized forms. A diffuse interstitial pattern is typically found in systemic disease. The characteristic radiologic patterns in interstitial amyloidosis include diffuse micronodular or reticulonodular. We present a case of amyloidosis which is unique in that the CT has a predominantly cystic pattern and the presence of interstitial lung disease is the only manifestation of amyloidosis.
A 47 yo male with no significant past medical history presented to his primary physician in 1999 complaining of increasing shortness of breath. He was diagnosed with reactive airways disease and was placed on inhaled steroids and beta-agonists without improvement. He was referred to a pulmonary physician in 2000, where he underwent PFT’s and a CT scan. PFT’s showed a restrictive pattern with significant air trapping. The CT scan showed diffuse interstitial disease with diffuse cysts. He was sent for open lung biopsy in October 2000, which revealed parenchymal nodules with amorphous eosinophilic extracellular material consistent with amyloid. An extensive search for systemic disease was negative. The patient reported to WRAMC in January 2003. He complained of increasing shortness of breath. PFT’s at that time showed an 800cc decrement in his FVC. At Walter Reed, the patient has undergone a second full evaluation searching for systemic amyloidosis. Again, he has no evidence of systemic disease. He is currently awaiting bone marrow biopsy.DISCUSSION: Pulmonary amyloidosis can occur in two distinct settings. Most commonly, it is seen as manifestation of a systemic disorder. A distinct entity of localized pulmonary amyloidosis has also been described. In this subset of patients, the pulmonary manifestations include tracheobronchial amyloidosis or nodular amyloid lesions. In general, the prognosis is excellent for these disorders. A diffuse interstitial pattern is decidedly rare without systemic disease. In the most recent series, Utz et al. evaluated all of the patients with pulmonary amyloidosis at Mayo Clinic from 1980 to 19931. Fifty-five patients were found to have pulmonary amyloidosis. In thirty-eight of these, the pulmonary symptoms were a manifestation of systemic disease. Of the seventeen patients with localized pulmonary disease, no patient had a diffuse interstitial pattern (4 tracheobronchial, 7 nodular, 6 senile). Hui et al published a retrospective study of 48 patients with amyloidosis localized to the lower respiratory tract2. They found 6 patients who had a diffuse interstitial pattern of involvement. However, in this series, there was a paucity of clinical information and the investigators were sure of the localized nature of the amyloidosis in only 6/48 patients. Therefore, the 6 cases of diffuse interstitial disease may not have had amyloidosis localized the the pulmonary tract.The reported cases with diffuse interstitial changes amyloidosis have rarely shown a predominance of cysts. Our patient presented with cystic lung disease with obstruction and air trapping. Review of the literature only show 2 cases that report a predominance of cysts, and only 1 of these was patient with localized pulmonary disease 3,4.
This case illustrates three important points to practicing pulmonologists. First, it argues for the need to take atypical cases of interstitial lung disease to lung biopsy. Secondly, it demonstrates that localized pulmonary amyloidosis can present as diffuse ILD and changes on HRCT may be predominantly cystic.
J.S. Wink, None.