Amyloidosis is a rare condition marked by the accumulation of abnormal protein deposits, known as amyloid fibrils, in various organs and tissues throughout the body. When these protein deposits specifically build up in the larynx, commonly referred to as the voice box, the condition is known as laryngeal amyloidosis. This localized form of amyloidosis is uncommon.
Understanding Laryngeal Amyloidosis
Amyloid deposits in the larynx can cause thickening and stiffness of the affected tissues. The larynx, which plays a role in voice production and breathing, is composed of three main parts: the supraglottis, glottis, and subglottis.
Laryngeal amyloidosis frequently affects the true vocal cords, false vocal cords, and the subglottis, which are all involved in voice production and maintaining an open airway. While the condition is often a localized form, it can occasionally be a manifestation of a systemic condition. The amyloid fibrils in laryngeal amyloidosis are most often composed of immunoglobulin light chains, specifically the AL (light chain) type, which are proteins produced by plasma cells.
Recognizing Symptoms and Diagnosis
Laryngeal amyloidosis often presents with symptoms related to voice changes and breathing. Hoarseness or other alterations in voice quality, medically termed dysphonia, is the most frequently reported symptom, affecting over half of individuals. These voice changes occur as amyloid deposits disrupt the normal vibration and closure of the vocal cords.
Difficulty breathing is another common symptom, and can be accompanied by wheezing or a high-pitched breathing sound called stridor. Some individuals may also experience a sensation of a lump in the throat, persistent cough, or difficulty swallowing (dysphagia).
The diagnostic process begins with an examination, such as a laryngoscopy, where a doctor can visually inspect the larynx for abnormal growths, which may appear as firm, yellowish, or grayish nodules. Imaging studies like CT scans can show thickening of the laryngeal soft tissues, while MRI can provide more specific details about the extent of the lesions. The definitive diagnosis is established through a biopsy of the laryngeal tissue, where the presence of amyloid deposits is confirmed. Pathologists use special stains, such as Congo red, which cause amyloid to exhibit a characteristic apple-green birefringence under polarized light microscopy.
Treatment Approaches
Treatment for laryngeal amyloidosis focuses on relieving symptoms and preserving the function of the voice box. Surgical removal of the amyloid deposits is the main treatment for symptomatic cases. Various endoscopic surgical techniques are employed, such as endoscopic laser excision, often using a CO2 laser, or cold endoscopic excision with instruments.
The goal of these surgical interventions is to debulk the amyloid deposits, especially in areas that interfere with breathing or voice production, rather than complete removal, which can be challenging due to the infiltrative nature of the deposits. For example, CO2 laser excision can precisely remove diseased tissue and reduce postoperative swelling. In some mild, asymptomatic cases, watchful waiting may be an option. If laryngeal amyloidosis is part of a broader systemic condition, systemic treatments may be considered, but local treatment for the larynx is more common.
Long-Term Outlook and Management
Laryngeal amyloidosis is generally considered a benign condition with a favorable outlook. However, recurrence of amyloid deposits after surgical removal is a common occurrence. Recurrences can happen anywhere from a few months to several years after the initial treatment.
Because of the likelihood of recurrence, long-term follow-up and monitoring are important for individuals with laryngeal amyloidosis. Regular check-ups with an ENT specialist are recommended to detect any new amyloid growth. While the condition is not typically life-threatening when localized to the larynx, it can significantly affect a person’s quality of life due to persistent voice changes or breathing difficulties if not appropriately managed. In some cases, voice therapy may also be beneficial to improve vocal function.