Laryngeal papillomatosis (recurrent respiratory papillomatosis — RRP) is the most common benign neoplasm of the respiratory tract, caused by human papillomavirus (HPV) types 6 and 11. The juvenile form (onset 2-5 years) is aggressive with frequent recurrences and is usually transmitted from mother during birth canal passage; the adult form (20-40 years) has a less aggressive course and is sexually transmitted. Papillomas are located on the vocal cords, subglottic region, epiglottis, and tracheobronchial tree. Imaging shows irregular, papillomatous mucosal thickening and nodularity in the airway; the superficial growth pattern without deep invasion is the most important distinguishing feature from SCC. Malignant transformation risk is 3-7%, with HPV type 11, radiotherapy history, and smoking as risk factors.
Age Range
2-50
Peak Age
5
Gender
Equal
Prevalence
Uncommon
The pathogenesis of RRP is based on HPV infection of basal epithelial cells. HPV types 6 and 11, although low-risk (non-oncogenic) types, cause persistent infection and papilloma formation in respiratory epithelium. The virus penetrates the epithelium at sites where the basement membrane is exposed (mucosal junction points such as the laryngeal ventricle entrance — squamocolumnar junction). Viral E6 and E7 oncoproteins disrupt cell cycle regulation, leading to epithelial hyperproliferation, but this effect is limited in low-risk types and malignant transformation is rare. Papillomas consist of stratified squamous epithelial proliferation over a vascularized fibrovascular core — this structure is reflected on imaging as irregular superficial thickening and moderate enhancement. Pulmonary spread (very rare, 1-3%) occurs distally through the tracheobronchial route, forming cavitary nodules; this condition indicates poor prognosis.
Irregular, papillomatous superficial mucosal thickening of vocal cords and subglottis with preserved paraglottic/pre-epiglottic spaces and cartilage structures — superficial growth + frequent recurrence history is a pathognomonic combination.
Contrast-enhanced CT shows irregular, nodular/papillomatous mucosal thickening of the vocal cords, subglottic region, and epiglottis. Lesions show moderate enhancement. Airway lumen narrowing may be present. Critically, paraglottic fat planes are preserved and cartilage invasion is absent — this is the most important distinguishing finding from SCC.
Report Sentence
Irregular papillomatous mucosal thickening is seen involving both vocal cords and the subglottic region, consistent with laryngeal papillomatosis; no findings of deep invasion are identified.
On MRI, papillomas appear as T2 hyperintense, T1 isointense mucosal lesions. Superficial growth pattern is preserved — paraglottic space and pre-epiglottic space show normal fat signal. Diffusion restriction is mild-moderate, not as marked as SCC. MRI is superior to CT in proving absence of deep invasion in SCC differential.
Report Sentence
T2 hyperintense superficial papillomatous lesions are seen on both vocal cords; paraglottic and pre-epiglottic spaces are preserved with no findings of deep invasion.
Pulmonary spread (very rare, 1-3%): multiple solid or cavitary nodules in the lungs. Cavitation reflects the airway luminal growth of papillomas. More common in posterior lower lobes. Nodules may enlarge over time and malignant transformation (SCC) may develop. Pulmonary involvement is a poor prognosis indicator.
Report Sentence
Cavitary nodules are seen in both lower lobes, consistent with pulmonary spread in the setting of known laryngeal papillomatosis.
Papillomas show mild-moderate diffusion restriction on DWI; ADC values typically range 1.2-1.6 × 10⁻³ mm²/s. This is distinctly different from the marked restriction of SCC (ADC <1.0-1.2). Due to low cellularity and benign nature, diffusion restriction is not as marked as SCC. ADC value can be used as a helpful quantitative parameter in differential diagnosis.
Report Sentence
Mild diffusion restriction (ADC: 1.4 × 10⁻³ mm²/s) is seen in the vocal cord lesions, consistent with benign papillomatous lesion.
Airway narrowing at the subglottic and glottic level results from endoluminal growth of papillomatous lesions. In children, even small lesions can cause significant obstruction because the airway diameter is small. Multiplanar reformat images (coronal/sagittal) and 3D airway reconstructions are helpful in assessing the degree and length of stenosis.
Report Sentence
Approximately 60% airway lumen narrowing is seen at the subglottic level due to papillomatous lesions.
Criteria
Onset age <12, usually 2-5 years
Distinct Features
Aggressive course, frequent recurrence (4+ operations/year), higher pulmonary spread risk, life-threatening airway obstruction
Criteria
Onset age >12, usually 20-40 years
Distinct Features
Less aggressive, fewer recurrences, usually single site involvement, pulmonary spread very rare
Criteria
Development of SCC from papilloma (3-7%)
Distinct Features
HPV 11, radiotherapy history, smoking are risk factors; development of deep invasion and cartilage destruction indicates transformation
Distinguishing Feature
SCC deep invasion, cartilage invasion, marked diffusion restriction (ADC <1.0); papillomatosis superficial, no deep invasion, mild diffusion restriction
Distinguishing Feature
Laryngocele cystic/air-filled, no enhancement; papillomatosis solid mucosal thickening, enhancement present
Distinguishing Feature
Hemangioma subglottic asymmetric mass, intense homogeneous enhancement, infant; papillomatosis multiple papillomatous lesions, moderate enhancement
Urgency
routineManagement
surgicalBiopsy
NeededFollow-up
3-monthRRP treatment is surgical excision (CO2 laser, microdebrider); the goal is to maintain airway patency and preserve voice quality. Recurrence rate is high (60-80% juvenile). Adjuvant therapies (cidofovir, bevacizumab, HPV vaccine) may reduce recurrence. Regular laryngoscopic follow-up is required. Risk factors for malignant transformation should be monitored.
Treatment of RRP is surgical excision (CO2 laser, microdebrider) but recurrence rate is high (60-80% in juvenile form). Adjuvant therapies (cidofovir, bevacizumab, HPV vaccine) may reduce recurrence rates. Malignant transformation is observed especially with HPV 11 and history of radiotherapy. Pulmonary spread is rare (1-3%) but significantly worsens prognosis.