Interventional Chest/Diagnostic Procedures (IC/DP) NetWork Online Puzzler - December 2008

Case Puzzler | 12.01.08

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Figure 1. Flow-volume loop.

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Figure 2A. Chest CT shows a soft tissue mass surrounding the trachea.

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Figure 2B. Reconstructed chest CT shows severe stenosis of the distal trachea and mainstem bronchi.

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Clinical presentation
The patient is a 35-year-old Caucasian woman reporting shortness of breath, wheezing, and cough during the last 4 years. She had been diagnosed with asthma and treated with albuterol with poor response. Her symptoms were exacerbated with exercise and during sleep.

Review of systems
No sinus congestion, nasal discharge, or postnasal drip. No heartburn.

Past medical and surgical history
A motor vehicle accident 15 years ago resulted in a left ankle injury requiring surgical repair.

Social history
The patient works as a secretary and denies any use of tobacco, alcohol, or illicit drugs. She is single and has no pets.

Family history
Asthma in a maternal great grandparent.

Allergies
None

Current medications

fluticasone propionate, 500 µg, and salmeterol, 50 µg (Advair Diskus 500/50; GlaxoSmithKline; Philadelphia, PA), one puff bid
montelukast sodium (Singulair; Merck & Co., Inc.; Whitehouse Station, NJ), 10 mg qd
chlorpheniramine and hydrocodone (Tussionex; UCB; Rochester, NY), prn prior to bedtime
albuterol metered-dose inhaler, as needed
escitalopram oxalate (Lexapro; Forest Pharmaceuticals, Inc.; New York, NY) 10 mg qd

Physical examination
BP = 119/80, heart rate = 92, respiratory rate = 22, temperature = 97.2, weight = 159 lb, height = 6'7”, oxygen saturation on room air = 96%
HEENT: Sinuses are nontender, nasal mucosa is inflamed without overt obstruction.
PULM: Coarse breath sounds bilaterally, with scant expiratory wheezes
CV: Regular, with no audible murmurs
ABD: Soft, nontender, no hepatosplenomegaly
EXT: No cyanosis, clubbing, or edema

Pulmonary function tests
FVC             4.32 (109 % of predicted)
FEV₁            1.54 (47% of predicted)
FEV₁/FVC      36
FEF_25-75%      1.13 (32% of predicted)

The flow-volume loop showed flattening of the inspiratory and expiratory limbs suggestive of fixed airway obstruction (Fig 1).

Due to the poor response to standard asthma treatment and the abnormal flow-volume loop, a chest CT was obtained and showed a large soft-tissue mass that surrounds the trachea, carina, and main bronchi and narrows the airway to a diameter of 4 mm at the level of the carina (Fig 2A, 2B).

See the Answer

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Figure 3. Bronchoscopic view of the distal trachea showing severe stenosis of the distal trachea and mainstem bronchi.

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Figure 4. Section of large airway containing an invasive neoplasm arranged in sheets and angulated infiltrative nests (hematoxylin-eosin, original x 100).

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Figure 5. Tumor features fused trabeculae, small acini, and areas of cribriform architecture. Cytologic detail includes intermediate size with hyperchromatic nuclei. The above findings are typical of adenoid cystic carcinoma (hematoxylin-eosin, original x 200).

Puzzler Answer and Case Report

Diagnosis
Tracheobronchial adenoid cystic carcinoma

Clinical course
A bronchoscopy was performed and showed severe stenosis of the distal trachea and both main stem bronchi due to tissue growth and extrinsic compression (Fig 3). Electrocautery was used to vaporize tissue in the mainstem bronchi. Further tissue debridement was performed using the barrel of the rigid bronchoscope to core out tissue. Metallic stents were placed in both mainstem bronchi with marked improvement in the lumens. Metallic stents were chosen over silicone stents, given the severe airway stenosis and anticipated poor prognosis.

The tissue specimens were examined histologically and revealed adenoid cystic carcinoma (Fig 4, 5).

Repeat PFT showed marked improvement:

FVC: 4.18 (106% of predicted)
FEV¹: 3.01 (91% of predicted)
FEV¹/FVC: 72

A multidisciplinary team consisting of thoracic surgery, oncology, radiation oncology, and pulmonary formulated a plan of treatment. The disease was deemed too extensive for surgical resection. The treatment plan consisted of 6 weeks of radiation with concurrent weekly treatment with cisplatin, followed by four courses of docetaxel and carboplatin. The patient is currently doing well with continued favorable response to the treatment.

Take-home points

Airway tumors may masquerade as asthma symptoms; physicians should be alert to the possibility of alternative diagnoses in asthma patients with poor response to standard therapy.
Adenoid cystic carcinoma is the most common salivary gland tumor found in the lung.
Adenoid cystic carcinoma generally occurs in the trachea or mainstem bronchi.
Complete resection is the most effective treatment.
The efficacy of radiation and chemotherapy is not well established and may be associated with a high recurrence rate.
Survival in nonresectable tumors is generally poor (10% survival at 10 years).

References

Gaissert HA, Grillo HC, Shadmer MB, et al. Long term survival after resection of primary adenoid cystic and squamous cell carcinoma of the trachea and carina. Ann Thorac Surg 2004; 78:1889-1897
Albers E, Lawrie T, Harrell JH, et al. Tracheobronchial adenoid cystic carcinoma: a clinicopathologic study of 14 cases. Chest 2004; 125:1160-1165
Chin HW, DeMeester T, Chin RY, et al. Endobronchial adenoid cystic carcinoma. Chest 1991; 100:1464-1465

Puzzler and case report submitted by:
Momen M. Wahidi, MD, FCCP
Director, Interventional Pulmonology
Duke University Medical Center
Durham, NC

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