What Is Your Diagnosis?

Guillaume C. Ruiz Internal Medicine Department, Université Paris-Est, Ecole Nationale Vétérinaire d'Alfort, 94704 Maisons-Alfort Cedex, France.

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Ghita Benchekroun Internal Medicine Department, Université Paris-Est, Ecole Nationale Vétérinaire d'Alfort, 94704 Maisons-Alfort Cedex, France.

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History

A 5-year-old 5.1-kg (11.2-lb) neutered female cat was evaluated because of a 3-day history of labored breathing, lethargy, and anorexia. The owner reported that the cat had respiratory signs of open-mouth breathing and wheezing both at rest and during exercise. The cat lived indoors but had access to a garden and was vaccinated, regularly dewormed, and treated for external parasites. Results of serologic testing for FeLV antigen and FIV antibody were negative.

On physical examination, the cat was overweight with a body condition score of 4 of 5. Tachypnea with increased inspiratory effort and inspiratory wheezing was observed, and a grade 1 of 6 heart murmur was auscultated. The remainder of the clinical examination results were unremarkable. Thoracic radiographs were obtained to investigate the cause of the dyspnea (Figure 1).

Figure 1—
Figure 1—

Right lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 5-year-old neutered male cat evaluated because of a 3-day history of labored breathing, which included open-mouth breathing and wheezing, lethargy, and anorexia.

Citation: Journal of the American Veterinary Medical Association 248, 9; 10.2460/javma.248.9.995

Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →

Radiographic Findings and Interpretation

On the lateral view, the thoracic tracheal lumen is abruptly and severely narrowed along its dorsal wall by a soft tissue opacity lesion (Figure 2). The sharp interface of the tracheal lumen and gradual tapering of the lesion into the dorsal tracheal border, without evidence of tracheal displacement, are signs compatible with a mural lesion. The tracheal lumen was narrowed by approximately 75%. The ventrodorsal view was of little value because the tracheal lesion was superimposed over the vertebral column. Differential diagnoses for the tracheal mural mass included inflammatory granuloma, polyp, tumor, and less likely, tracheal avulsion following hyperextension of the head.

Figure 2—
Figure 2—

Same lateral radiographic image of Figure 1 with magnification of the thoracic trachea. Notice the tapering soft tissue opacity within the dorsal aspect of the thoracic trachea. The mass is causing severe narrowing of the tracheal lumen (arrows).

Citation: Journal of the American Veterinary Medical Association 248, 9; 10.2460/javma.248.9.995

The cat was premedicated by IV administration of butorphanol and midazolam, and general anesthesia was induced and maintained with IV administration of propofol. Tracheoscopy was performed and confirmed a soft tissue mass occluding the tracheal lumen; the tracheal mucosa was intact. Endoscopic biopsy specimens of the mass were obtained. Findings on histologic evaluation of the mass revealed variable amounts of neutrophils, lymphocytes, and macrophages and were consistent with an inflammatory granuloma.

Treatment and Outcome

The cat recovered well from tracheoscopy. Prednisolone (1 mg/kg [0.45 mg/lb], PO, q 24 h) was prescribed for 1 week, followed by fluticasone (250 μg by inhalation, q 12 h) for 7 weeks. While histologic findings were pending, a 5-day course of fenbendazole (50 mg/kg [22.7 mg/lb], PO, q 24 h) was initiated to treat a potential parasitic granuloma.

Clinical signs completely resolved a few days after initiating treatment. At the end of the 2-month treatment period, no abnormalities were detected on physical examination. The trachea appeared normal on follow-up thoracic radiography. Therefore, the inhalation treatment with fluticasone was gradually tapered and eventually completely discontinued. The cat was clinically normal at reexamination at 1 year after diagnosis.

Comments

Tracheal masses are rarely described in cats.1–4 Dyspnea is the most common clinical sign (17/27 [63%] cats with laryngeal, laryngotracheal, and tracheal masses had dyspnea in a study by Jakubiak et al1), but coughing, wheezing, anorexia, and weight loss are also common clinical signs in affected cats. Wheezing suggests airway constriction but is not specific for a tracheal lesion. Thoracic radiography is indicated to investigate wheezing in cats. Wheezing can arise from a variety of geographic regions within the airways; therefore, for complete radiographic evaluation, it is important to also include laryngeal and cervical areas of the neck to avoid missing a laryngeal or cervical tracheal mass.1

Radiographic findings indicating a tracheal mass in a cat include a mural soft tissue opacity and a narrowed tracheal lumen.1 However, 10% of cats with laryngeal or tracheal masses have no radiographic lesions.1 When radiographic findings are inconclusive, alternative modalities such as endoscopy or CT are required.

Various types of tracheal masses have been described, with neoplasia the most common etiology.1–4 In cats, lymphoma and carcinoma are the most common types of tracheal tumors. Few cases of strictly inflammatory tracheal masses have been reported, and their etiology is generally unclear. A mycobacterial-associated granuloma was recently described in a cat.4

It has been suggested that a tracheal granuloma may occur subsequent to trauma or viral infection.1 In the case described in the present report, no trauma was reported, and no sign of infection was identified on histologic evaluation of the mass. Although radiographic findings cannot be used to distinguish between inflammatory and neoplastic masses, radiography remains important in differentiating between intraluminal obstructive, mural obstructive, and extraluminal compressive masses (eg, from the esophagus or lymph nodes). Extraluminal masses generally cause tracheal deviation before narrowing of the lumen.

In the cat of the present report, the tracheal mass was easily seen on the lateral thoracic radiographic view. The protrusion of the mass into the lumen, lack of ventral deviation of the trachea, and gradual tapering of the mass into the tracheal border were consistent with a lesion of mural origin, which warranted the use of tracheoscopy for verification and biopsy. Follow-up radiography provided a noninvasive way to evaluate the status of the mass following treatment. Although a small remnant mass could not be ruled out at follow-up examination, the lack of a lesion on repeated thoracic radiography was consistent with the clinical improvement and led to discontinuation of treatment. The complete recovery with corticosteroid treatment and the absence of relapse support a diagnosis of inflammatory granuloma. Because fenbendazole was administered to the cat, possible parasitic involvement in granuloma development cannot be completely ruled out, although evidence of a parasitic infection was not observed on histologic evaluation of the mass.

References

  • 1. Jakubiak MJ, Siedlecki CT, Zenger E, et al. Laryngeal, laryngotracheal, and tracheal masses in cats: 27 cases (1998–2003). J Am Anim Hosp Assoc 2005; 41:310316.

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  • 2. Roach W, Krahwinkel DJ Jr. Obstructive lesions and traumatic injuries of the canine and feline tracheas. Compend Contin Educ Vet 2009; 31:8693.

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  • 3. Sheaffer KA, Dillon AR. Obstructive tracheal mass due to an inflammatory polyp in a cat. J Am Anim Hosp Assoc 1996; 32:431434.

  • 4. De Lorenzi D, Solano-Gallego L. Tracheal granuloma because of infection with a novel mycobacterial species in an old FIV-positive cat. J Small Anim Pract 2009; 50:143146.

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  • Figure 1—

    Right lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 5-year-old neutered male cat evaluated because of a 3-day history of labored breathing, which included open-mouth breathing and wheezing, lethargy, and anorexia.

  • Figure 2—

    Same lateral radiographic image of Figure 1 with magnification of the thoracic trachea. Notice the tapering soft tissue opacity within the dorsal aspect of the thoracic trachea. The mass is causing severe narrowing of the tracheal lumen (arrows).

  • 1. Jakubiak MJ, Siedlecki CT, Zenger E, et al. Laryngeal, laryngotracheal, and tracheal masses in cats: 27 cases (1998–2003). J Am Anim Hosp Assoc 2005; 41:310316.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2. Roach W, Krahwinkel DJ Jr. Obstructive lesions and traumatic injuries of the canine and feline tracheas. Compend Contin Educ Vet 2009; 31:8693.

    • Search Google Scholar
    • Export Citation
  • 3. Sheaffer KA, Dillon AR. Obstructive tracheal mass due to an inflammatory polyp in a cat. J Am Anim Hosp Assoc 1996; 32:431434.

  • 4. De Lorenzi D, Solano-Gallego L. Tracheal granuloma because of infection with a novel mycobacterial species in an old FIV-positive cat. J Small Anim Pract 2009; 50:143146.

    • Crossref
    • Search Google Scholar
    • Export Citation

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