A 53-year-old man had a history of chronic cough and wheezing, recurrent lower respiratory tract infections, and progressive shortness of breath. Asthma had been misdiagnosed in the previous 3 years of this patient, and his therapy included an inhaled beta-adrenergic agonist and glucocorticoid. He denied coughing, stridor, and hemoptysis. His medical history was not significant for tobacco abuse.
On admission, his temperature was 36.9
, pulse rate was 89 beats/min, respiratory rate was 19 breaths/min, and BP was 135/85 mm Hg. Auscultation of his lungs revealed diffuse rhonchi, and palpation revealed no abdominal organomegaly. The results from the examination of the centural nervous system (CNS) and skin were normal. Furthermore, physical examination of oral cavity and oropharynx was normal.
The results of his blood, chemistry, liver function, urine tests including creatinine clearance rate, urinalysis for urinary protein, beta-2 microglobulin, and serum immunoglobulin levels, renal ultrasonography, echocardiography, and electrocardiography were normal. Assays for human immunodeficiency virus and antineutrophil cytoplasmic antibodies were negative, and his rapid plasma reagin was nonreactive. Pulmonary function tests were indicative of an obstructive airway disease [Forced Vital Capacity (FVC): 49% of predicted, Forced Expiratory Volume (FEV) 1: 43% of predicted and FEV1/FVC: 68% of predicted], and the reversibility test was found to be negative.
The chest radiograph at admission showed homogenous opacity in the right middle lobe which is consistent with the symptoms of atelectasia.
Computed tomography showed the prominent cartilaginous nodules protruding into the airway lumen. Other roentgenologic findings include the thickening or irregularity of the tracheal and/or bronchial walls with sparing of the membranous posterior wall, deformed tracheal cartilage rings without evidence of external compression or submucosal calcification, and atelectasis of the right middle lobe ().
Computed tomography reveals irregular thickening of the tracheal wall with sparing of the membranous posterior wall and deformed tracheal cartilage rings without the evidence of external compression or submucosal calcification.
Fiberoptic bronchoscopic examination revealed mucosal nodules protruding into the lumen of the trachea (). These lesions extended throughout the trachea but extended especially in the middle and lower thirds; nodules were also present in the carina and in the medial wall of the two main bronchi. The posterior walls of the trachea and main bronchi were characteristically not involved. The lumen of the right middle lobe bronchus was completely obstructed. The initial diagnosis was tracheopathia osteoplastica based only on visual inspection through bronchoscopy. Multiple biopsies from the mucosal nodules demonstrated hyalinised, degenerated nodules of cartilage that were associated with fibrous tissue, spotty calcifications and homogenous, eosinofilic nodules in the submucosa (). However, amyloidosis was added to the diagnosis because characteristic findings of amyloid were obtained in tissue specimens stained by hematoxylin-eosin and congo red dye, and these specimens exhibited green birefringence under polarized microscopy ( and ).
Flexible bronchoscopic results show nodular lesions that arise from the anterior and lateral aspects of tracheal wall narrowing its lumen. The posterior tracheal wall was unaffected.
Homogenous proteinous material with calcification under bronchus epithelium (hematoxylin-eosin ×100).
Proteinous material was found to be positive with congo red stain (histochemistry ×200).
Amyloid deposition shows green birefringence under polarized microscopy (histochemistry ×200).
The patient underwent extensive testing in order to rule out systemic amyloidosis. Fat pad aspirates, a highly sensitive assay for systemic amyloid deposition, did not bind to the congo red stain. Serum or urine protein electrophoreses failed to detect any monoclonal protein. Bone marrow biopsy and aspirate did not identify plasmacytosis. The case did not exhibit clonal expansion of the kappa or lambda light chain immunoglobulin in the bone marrow through immunohistochemical staining. Resting electrocardiograms or echocardiograms did not manifest any signs of infiltrating cardiac disease.