Teaching Case

A 17-year-old female presents with 3 months progressive dysphonia, hoarseness and mild dyspnoea. Two episodes of pneumonia in the last five years were reported. The clinical examination was unremarkable. A chest radiograph and CT scan were performed, as well as laryngoscopy, which revealed a supraglottic polypoid lesion that was biopsied.

Pathologic evaluation of the specimen revealed a squamous cell papilloma.

The chest radiograph revealed no significant changes. Chest CT was performed to evaluate the pulmonary parenchyma. Numerous thin-wall cystic lesions were identified in the lung parenchyma, some of which were lobulated and confluent, with bilateral distribution, predominantly on the right inferior lobe (Fig.1a-c). There was also a small number of infracentimetric and pericentimetric solid lesions (Fig. 1d-e).

There were no parenchymal consolidations, atelectasis, bronchiectasis, nor mucus plugging.

A polypoid vegetant lesion was also depicted in the supraglottic space, posterior and inferior to the right aryepiglottic fold, with 11 mm (Fig. 2).

Recurrent respiratory papillomatosis (RRP) is generally a benign disease, caused by low-risk human papillomavirus (HPV) subtypes 6 and 11, and characterised by the appearance of multiple squamous cell papillomas involving the respiratory tract. Most commonly, the lesions affect the larynx and less commonly the trachea and bronchial tree. Only 1% of cases show pulmonary involvement. Focal or diffuse airway narrowing is caused by the nodular vegetant lesions, which occur on the mucosal surface, projecting into the airway lumen [1, 2]

Although it is unclear how HPV infection progresses to RRP, a recent study shows the presence of pepsin inside the pharyngeal mucosal cell in 45.5% of children with RRP. Pepsin, present in laryngopharyngeal reflux, could cause or facilitate many pathologies in children, contributing to development of RRP by activating or reactivating latent HPV infection [3, 4]

The disease has a higher incidence in children, being the most common benign laryngeal neoplasia in this age group. The most common clinical manifestations are hoarseness, cough, stridor, dyspnea and recurrent respiratory infections [2, 5].

Chest CT is the preferred imaging technique for identification and characterization of tracheobronchial polypoid lesions and recognition of small nodules during the pulmonary dissemination phase. The characteristic CT patterns are solid nodular or polypoid lesions in the trachea, which can be single or multiple, and solid nodules scattered throughout the lung parenchyma, more numerous in the basal and posterior regions of the lungs, with a centrilobular distribution, typically confluent. These nodules may enlarge and cavitate, becoming air-filled cysts, forming large cavities with irregular internal borders, and with thick or thin walls. Less prevalent findings comprise mass, consolidation, air trapping, and pleural effusion. [2, 6, 7]

Regular follow-up with CT is recommended due to the rare possibility of malignant transformation [6, 7].

The diagnosis is made after histopathological analysis of laryngeal or tracheal samples, collected by laryngoscopy or bronchoscopy [3, 5].

The course of the disease is unpredictable, ranging from spontaneous remission to aggressive disease progression, spreading to the lungs, and it may require multiple surgical procedures to maintain the airway function.

The estimated malignancy rate of RRP is approximately 3-7% in adults and less than 1% in children [1, 5, 6].

No definitive curative treatment for RRP is currently available, being surgical excision the current standard of care. Most recently, multivalent HPV vaccine has been used to manage RRP with promising outcomes; HPV vaccination is central in prophylaxis and the disease may be eliminated with universal vaccination [1, 7].

Written informed patient consent for publication has been obtained.