Recurrent Respiratory Papillomatosis (RRP)
Recurrent respiratory papillomatosis (RRP) is a rare disorder characterized by the development of small, wart-like growths (papillomas) in the respiratory tract.
Papillomas are common lesions of the larynx and other sites where ciliated and squamous epithelia meet. Unlike oral papillomas, recurrent respiratory papillomatosis typically becomes symptomatic, with hoarseness that occasionally progresses over weeks to months. These papillomas are almost always due to HPV types 6 and 11.
Papillomas are noncancerous (benign), but in extremely rare cases can undergo cancerous (malignant) transformation. Although benign, papillomas can cause severe, even life-threatening airway obstruction and respiratory complications. In RRP, papillomas have a tendency to grow back after they have been removed.
Signs & Symptoms
The specific symptoms, course of the disease, and severity of RRP can vary greatly from one person to another. In some cases, the disease may resolve without treatment (spontaneous remissions) or it may remain stable requiring only periodic intervention (e.g. only a few surgeries during their lifetime). In other cases, the disease may be aggressive requiring frequent medical intervention and potentially more than 100 surgeries during a person’s lifetime.
The most common presenting symptom of RRP is hoarseness. Hoarseness may become progressively worse and the voice of an affected individual may be weak, raspy or sound low in pitch or strained. The severity of voice problems can vary from one person to another due, in part, to the size and specific locations of papillomas. Affected individuals may develop labored, noisy breathing (stridor) due to obstruction of the airway. Initially, stridor may occur when breathing in (inspiratory stridor), but eventually occurs both when breathing in and out (biphasic stridor). Some individuals may exhibit difficulty speaking (dysphonia) or lose their voice entirely (aphonia). Affected infants may also have a weak cry, episodes of choking and fail to grow and gain weight at the expected rate (failure to thrive).
Additional symptoms that can develop include a chronic cough, difficulty swallowing (dysphagia), shortness of breath or difficulty breathing (dyspnea), the sensation of a foreign body in the throat, and choking episodes.
Left untreated, papillomas can eventually compromise the airways, resulting in life-threatening breathing difficulties (acute respiratory distress). If RRP spreads to the lungs, affected individuals can potentially experience recurrent pneumonia, chronic lung disease (bronchiectasis) and, ultimately, progressive pulmonary failure. In extremely rare cases (i.e. less than 1% of cases), papillomas can become cancerous (malignant transformation) developing into squamous cell carcinoma.
Repeated laser vaporizations or cold knife resections via operative laryngoscopy are the mainstay of treatment. Severe cases can cause airway compromise in adults and may require treatment as often as every 6 weeks to maintain airway patency. Extension can occur into the trachea and lungs. Tracheotomy should be avoided, if possible, since it introduces an additional squamociliary junction for which papillomas appear to have an affinity.
Interferon treatment has been under investigation for many years but is only indicated in severe cases with pulmonary involvement. Rarely, cases of malignant transformation have been reported (often in smokers), but recurrent respiratory papillomatosis should generally be thought of as a benign condition. Cidofovir (a cytosine nucleotide analog in use to treat cytomegalovirus retinitis) has been used with success as intralesional therapy for recurrent respiratory papillomatosis.
Because cidofovir causes adenocarcinomas in laboratory animals, its potential for carcinogenesis is being monitored. The quadrivalent and new 9 serotype recombinant human HPV vaccines (Gardasil and Gardasil 9) offer hope for the eventual prevention of this benign, but terribly morbid, disease.