Radiological case of the month: William T. O'Brien, Sr., DO, Matthew D. Duncan, MD, Grant E. Lattin, Jr., MD, Edward L. Jackson, MD, and Patrick J. Danaher, MD.
A 65-year-old man with adult-onset tracheal papillomatosis and a remote smoking history presented with a 2-week history of low-grade fevers, a productive cough, and shortness of breath. He was tachypneic and tachycardic on presentation. Physical examination was significant for inspiratory rales along the right anterior chest wall. A chest X-ray showed patchy consolidation within the right middle lobe (Figure 1A). Based upon clinical and radiographic findings, the patient was treated for suspected community-acquired pneumonia. Despite appropriate antibiotic treatment, the patient's shortness of breath and sputum production progressed during the next 6 weeks, with worsening of the right middle lobe consolidation (Figure 1B). Further work-up included contrast-enhanced computed tomography (CT) (Figure 2), CT virtual bronchoscopy (Figure 3), and bronchoscopic evaluation.
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The initial chest radiograph showed patchy consolidation within the right middle lobe, which was suggestive of pneumonia based upon the clinical findings (Figure 1A). A repeat chest X-ray obtained 6 weeks posttreatment showed worsening right middle lobe consolidation (Figure 1B). Contrast-enhanced CT showed the partial collapse of the right middle lobe with postobstructive pneumonitis. On coronal and sagittal reformatted images, multiple tracheal lesions were identified (Figure 2); however, no obstructing endobronchial lesions were seen in the region of the right middle lobe bronchus. Virtual bronchoscopy was performed, which identified multiple tracheal lesions (consistent with tracheal papillomatosis), as well as an endobronchial lesion that was obstructing the right middle lobe bronchus (Figure 3). Subsequent bronchoscopy confirmed these findings.
Endobronchial squamous cell carcinoma from malignant transformation of tracheal papillomatosis
Bronchoscopic biopsy of the right middle lobe endobronchial lesion revealed dysplastic squamous cell papilloma. Endobronchial brushings were positive for squamous cell carcinoma. Staging evaluation, which included positron emission tomography, was negative for metastatic disease. The patient subsequently underwent a right sleeve pneumonectomy; however, he tragically died secondary to intraoperative flash pulmonary edema in the left lung. Postmortem evaluation revealed widespread squamous cell carcinoma throughout the right lung and mediastinum, likely resulting from the malignant transformation of the patient's papillomatosis.
Tracheal papillomatosis is a subset of a broader category of recurrent respiratory papillomatosis (RRP). The papillomas are caused by the human papilloma virus (HPV). As in cervical pathology, types 6 and 11 cause benign papillomas, whereas types 16 and 18 have been linked to squamous cell cancer. The disease process is divided into 2 main groups: childhood-onset and adult-onset RRP. The incidence of childhood-onset RRP is estimated to be approximately 4.3 cases per 100,000 children, while the incidence of adult-onset RRP is estimated to be approximately 1.8 cases per 100,000 persons. (1) The true incidence rate of tracheal papillomatosis is not known because of its rarity as a specific subset of RRP.
The cause of tracheal papillomatosis in children is thought to be secondary to exposure to the virus during vaginal childbirth. (2) For adult-onset tracheal papillomatosis, the current belief is that the infection stems from oroanal or orogenital contact with an infected individual. (3) The course of the disease process varies based upon whether it is the childhood--or adult-onset form; the childhood-onset form is far more aggressive.
Patients usually present with recurrent respiratory tract infections or obstructive symptoms that can often go undiagnosed or misdiagnosed as asthma or chronic bronchitis. The diagnostic dilemma relates to the rarity of the disease, as well as the slow progression of symptoms. Diagnosis is usually made during a work-up of obstructive symptoms. Computed tomography is the noninvasive modality of choice in detecting lesions within the trachea or bronchi. Once the diagnosis is suggested through noninvasive imaging, bronchoscopic biopsy provides a definitive diagnosis.
Current treatment modalities for benign papillomas include surgical removal, laser ablation, and a host of antiviral and immune-augmenting medical therapies. (4) Varying results have been found with each modality; however, surgical removal and laser ablation remain the mainstays of current treatment with adjuvant medical therapy. A very small percentage of patients suffer from malignant transformation of the HPV to squamous cell carcinoma, as was likely the case with our patient. The risk factors for malignant transformation include smoking, prior irradiation, and infection with HPV type 16. (5) When malignant transformation occurs, treatment typically depends on the stage of the cancer at presentation; however, it is nearly uniformly fatal.
This case highlights important imaging points. First, adult patients who present with clinical symptoms and radiographic findings of pneumonia should be reimaged posttreatment to exclude an underlying malignancy that can mimic an infectious infiltrate. (6) At our institution, all patients who are 35-years-old or older receive repeat radiographs 6 to 8 weeks posttreatment. If any residual consolidation is identified, a contrast-enhanced CT scan is recommended to exclude an obstructing endobronchial lesion.
Second, with the increased utilization of multidetector CT scans, the utility of virtual bronchoscopy will become more evident. We typically perform virtual bronchoscopy on all patients with suspected endobronchial lesions. Additionally, our pulmonary and critical care staff request virtual bronchoscopy as a guide to their bronchoscopic procedures. In the case of this patient, the right middle lobe endobronchial lesion would not have been found (with noninvasive testing) had it not been for the use of virtual bronchoscopy.
(1.) Derkay CS. Task force on recurrent respiratory papillomatosis: A preliminary report. Arch Otolaryngol Head Neck Surg. 1995;121:1386-1391.
(2.) Shah KV, Stern WF, Shah FK, et al. Risk factors for juvenile-onset recurrent respiratory papillomatosis. Pediatr Infect Dis J. 1998;17:372-376.
(3.) Kashima HK, Shah F, Lyles A, et al. A comparison of risk factors in juvenile-onset and adult-onset recurrent respiratory papillomatosis. Laryngoscope. 1992;102:9-13.
(4.) Green GE, Bauman NM, Smith RJ. Pathogenesis and treatment of juvenile onset recurrent respiratory papillomatosis. Otolaryngol Clin North Am. 2000; 33:187-207.
(5.) Doyle DJ, Henderson LA, LeJeune FE, Miller RH. Changes in human papillomavirus typing of recurrent respiratory papillomatosis progressing to malignant neoplasm. Arch Otolaryngol Head Neck Surg. 1994;120:1273-1276.
(6.) Shah PB, Giudice JC, Griesback R, et al. The newer guidelines for the management of community-acquired pneumonia. J Am Osteopath Assoc. 2004;104:521-526.
Prepared by William T. O'Brien, Sr., DO, Matthew D. Duncan, MD, Grant E. Lattin, Jr., MD (Department of Radiology), Edward L. Jackson, MD (Pulmonary and Critical Care Medicine), and Patrick J. Danaher, MD, (Department of Infectious Diseases), David Grant U.S. Air Force Medical Center, Travis Air Force Base, CA.
The views expressed in this material are those of the authors, and do not reflect the official policy or position of the U.S. Government, the Department of Defense, or the Department of the Air Force.
William T. O'Brien, Sr., DO, Matthew D. Duncan, MD, Grant E. Lattin, Jr., MD, Edward L. Jackson, MD, and Patrick J. Danaher, MD
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|Author:||O'Brien, William T.; Duncan, Matthew D.; Lattin, Grant E.; Jackson, Edward L.; Danaher, Patrick J.|
|Date:||Sep 1, 2007|
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