INTRODUCTION: Amyloidosis is a group of disorders characterized by deposition of protein conglomerates in extracellular tissue. The respiratory system may be involved either locally or as part of a systemic process. Tracheobronchial, laryngeal, or parotid gland involvement are rare types of localized amyloidosis. To our knowledge, we report the first case of a patient with combined tracheobronchial, laryngeal, and parotid gland amyloidosis.
CASE PRESENTATION: A 72-year-old woman presented to an outside facility with a few days of dry mouth, sore throat, and cough. She was treated for aspiration pneumonia and discharged two days later. The next day, the patient went to see her otolaryngologist who has been following her for chronic bilateral parotid gland enlargement. A parotid biopsy in 2000 was reported to show nonspecific chronic mild inflammation. Her past medical history was significant for coronary artery disease, and hypertension. Due to the presence of nasal and oral cavity blood, the patient underwent flexible nasopharyngoscopy which revealed a swollen and bleeding larynx and nasopharynx. Biopsies of the false vocal folds and parotid glands were performed. Post-extubation, the patient had a sudden drop in oxygen saturation and was reintubated with difficulty. The patient continued to have hemoptysis. Bronchoscopy revealed blood-filled airways, very friable mucosa, and a nodular irregular area in the distal trachea that was biopsied. All off the biopsies (parotid gland, false vocal folds, and trachea) were found to contain amyloid deposits by Congo red staining. Serum and urine electrophoresis did not show a gammopathy. An echocardiogram showed no evidence of cardiac amyloidosis. A tracheostomy was performed and she was discharged home 4 weeks after admission in a stable condition.
DISCUSSIONS: Pulmonary amyloid may be a manifestation of systemic disease or a local disease confined to the lungs. Diffuse interstitial involvement is the most common pattern seen in systemic disease. Local disease may occur in the airways (tracheobronchial) or the parenchyma (amyloidomas). Tracheobronchial amyloidosis is uncommon with only few hundred cases reported. It typically presents after the fifth decade with dyspnea, cough, and occasionally hemoptysis. It may lead to progressive airway obstruction, infectious complications, and respiratory failure. Laryngeal amyloidosis occurs most commonly in the supraglottic region. It is often asymptomatic, but can present with hoarseness, stridor, or a sensation of fullness. Fatal hemorrhage has been reported. Localized parotid gland involvement is extremely rare. The first case was described in 1998. It may cause the sicca syndrome and is often misdiagnosed as Sjogren's syndrome. The gold standard histological characteristic of amyloidosis is the unique green birefringence seen when Congo red stained tissue is viewed under a polarizing microscope. Management options for airway disease include surgical or bronchoscopic debridement, balloon dilation, Nd:YAG laser therapy, stent placement, and most recently radiation therapy.
CONCLUSION: Amyloidosis may involve all levels of the respiratory tract. We believe that this is the first case in which tracheobronchial, laryngeal, and parotid amyloidosis were found in a single patient. Early recognition is important as interventions effectively treat or delay serious complications associated with airway obstruction and hemorrhage. Differentiating local from systemic amyloidosis is also critical as the latter is associated with potentially treatable systemic diseases and carries a worse prognosis.
DISCLOSURE: Wael Berjaoui, None.