A 34-year-old man with chest pain and lung cyst

A 34-year-old man presented with a history of left-sided chest pain and intermittent non-productive cough, along with dyspnoea on exertion for one year. There was no history of fever, wheezing, or haemoptysis. On clinical examination, his vitals and systemic examination were normal. Cardiac evaluations, including electrocardiogram and 2D echocardiography, were normal. A high-resolution computed tomography (HRCT) scan of the thorax showed a large cyst in the left lower lobe with thin irregular walls along with another small thin-walled cyst located adjacent to the larger cyst. The rest of the surrounding lung parenchyma was normal. There was no mediastinal lymphadenopathy or pleural/pericardial effusion [Figure 1].Figure 1: Axial CT thorax image showing a large thin-walled, irregular cyst in the left lower lobe lung, with a smaller adjacent lung cyst. The rest of the lung parenchyma is normal. There is no significant mediastinal lymphadenopathyThe patient had been referred to our facility from the ENT department. He was a known case of recurrent respiratory papillomatosis (RRP) diagnosed at three years of age. The patient had undergone multiple sessions of laryngoscopic surgical excision of recurrent laryngeal papillomas, followed by tracheostomy, and later successful decannulation was done at 12 years of age. The patient had undergone tracheal papilloma resection and tracheal dilatation two years ago. After a review of clinical history and radiology, a flexible bronchoscopy was planned. On bronchoscopic examination, grade 1 tracheal stenosis was noted in the subglottic region with tracheal mucosa showing a small wart/papilloma-like lesion [Figure 2]. Bronchoalveolar lavage (BAL) workup was negative for infective and malignant aetiologies. The patient was managed with a course of antibiotics and had symptomatic improvement. This patient was followed up for a year and currently, he is asymptomatic, and a repeat CT chest showed similar findings with no significant radiological progression.Figure 2: Bronchoscopic image of patient showing mild tracheal stenosis in the subglottic region (left panel), and a small papillomatous lesion in the anterior tracheal mucosa (right panel)QUIZ What is the diagnosis? ANSWER Lung cysts due to recurrent respiratory papillomatosis (RRP). DISCUSSION Recurrent respiratory papillomatosis (RRP) is an uncommon benign disease of the upper airways caused by human papillomavirus (HPV). The primary lesions usually arise in the larynx. Although it can spread throughout the respiratory tract, involvement of the lung parenchyma is rare.[1] The disease course is usually unpredictable, ranging from spontaneous remission, aggressive persistent or recurrent disease, to malignant transformation into squamous cell carcinoma.[2] RRP affects primarily children and young adults in a characteristic bimodal distribution pattern. The juvenile form is generally aggressive with multiple papillomatous lesions and high recurrence rates, which develops in patients younger than 20 years. The adult forms, which develop after 20 years more commonly in males, are usually more benign with solitary papilloma and less recurrence.[3] Rarely, the adult form may present with extensive tracheobronchial involvement with respiratory failure.[4] Soldatski et al.[5] reported 448 patients with RRP in a 25-year interval and involvement of the lung parenchyma was present in only 1.8% of patients. Most of the cases of lung parenchymal involvement were seen in paediatric patients. Lung cysts are well described in respiratory papillomatosis. Chest radiology shows bilateral, multiple thin-walled cysts and nodular papillomas. Cysts are seen predominantly in the lower lobe distribution, although upper lobe involvement is not uncommon. The cyst walls are usually smooth but asymmetric thick walls (2–3 mm) are seen often. Cysts may be round or irregular in shape, and cysts with irregular contours often have thicker walls. Cysts are usually less than 5 cm diameter in size and may increase in size as the disease progresses. Air-fluid level in cysts can be seen occasionally.[5] The papillomas in the lungs, either nodules or masses, often have lobulated margins. Nodular lesions (<3 cm in diameter) have been reported to be more common than masses. The complications include post-obstructive atelectasis, bronchiectasis, secondary infections, or rarely malignant transformation can be seen.[6] There is no definite curative treatment for RRP; surgical excision of the papillomas, however, remains the mainstay of treatment to maintain airway luminal patency, improve quality of voice, and facilitate remission. The treatment usually involves repeated surgical debulking using a micro-debrider. Other ablative therapies, like cryotherapy, argon plasma coagulation, electrocautery, and laser photo resection, have been attempted to relieve airway obstructions. Intra-lesional injections with cidofovir and subcutaneous interferon therapy have been tried in some moderate-to-severe cases. Tracheostomy may be required for extensive disease with a risk for airway obstruction.[7] Our case highlights the presentation of recurrent respiratory papillomatosis with lung parenchymal involvement in the form of cysts involving the lower lobe. Chest CT is a more sensitive diagnostic tool for detecting small cysts and nodules and is a better modality for assessing the extent and severity of the disease. Awareness of the clinical presentation and the possible treatment options along with a multidisciplinary team involving ENT surgeon and interventional pulmonologist helps to improve outcomes in such complex cases. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.