Infectious laryngitis simulating a laryngeal tumour

A 53-year-old woman presented with sore throat, dysphagia and hoarseness, with two weeks of duration, and was treated initially with antibiotic therapy. Two weeks later the symptoms persist, now with stridor. On laryngoscopy, a swelling above the anterior part of the vocal cords and in the anterior commissure was seen.

CT demonstrated an enhancing and ill-defined lesion with irregular margins at the anterior commissure and base of the epiglottis, extending into both false vocal cords and into the lower part of the preepiglottic and paraglottic spaces bilaterally. There was diffuse swelling of the strap muscles, in which a nodular enhancing region was observed. Slightly enlarged lymph nodes in the level II, bilaterally, were also found, with ovoid morphology and pericentimetric short axis, as well as a prominent lingual tonsil.

The differential diagnosis included a tumoral lesion of the larynx with extralaryngeal extension, a granulomatous condition involving the larynx (such as tuberculosis or sarcoidosis), or an infectious process, due to the pronounced enhancement of the lesion (more than what is usually seen in squamous cell carcinomas), and the diffuse thickening of the strap muscles.

A direct laryngoscopy with biopsy was done, for anatomopathological examination and culture of the tissue, as well as a debulking of the mass to widen the breathing space. The removed laryngeal tissue showed histologically no malignancy, but findings of chronic inflammation. Culture revealed a Pseudomonas aeruginosa infection.

Background

Laryngitis refers to inflammation of the larynx and can be infectious or noninfectious [1]. Most infectious cases are acute, resulting from viral infections [2]. Chronic laryngitis occurs when symptoms persist for a minimum of 3 weeks, and causes include gastroesophageal reflux, asthma, allergies, vocal misuse, granulomatous and fungal infections, and systemic diseases such as sarcoidosis, rheumatoid arthritis, and granulomatosis with polyangiitis [2].

Clinical perspective

Patients can present with hoarseness, early vocal fatigue, or dry cough, and in severe cases, with dyspnea or stridor. Laryngeal malignancy can mimic laryngitis and should be suspected in patients with risk factors, such as smokers and immunocompromised [1], especially if symptoms persist for more than 2 weeks without a known benign cause, in which cases laryngoscopy is the first line of investigation [3,4]. Culture is recommended in suspected cases of infectious laryngitis, and biopsy is needed for the diagnosis of several noninfectious causes [2,3].

Imaging perspective

The primary role of imaging is to look for a mass lesion in the laryngopharynx and to exclude abscess formation. It should be performed prior to biopsy in order to avoid misinterpretation of biopsy trauma as an underlying disease [1,2,4,5]. Inflammation of the larynx can present as thickening of several laryngeal structures, submucosal oedema, and narrowing of the airway [1,5]. Erosion of the laryngeal cartilage can also occur, although being more suggestive of a laryngeal tumour [6]. In this case, the findings were worrying for a tumoral lesion, but the degree of enhancement and the associated diffuse thickening of the strap muscles were more suggestive of an inflammatory/infectious process, which was later confirmed by culture, and progressive resolution of the imaging findings with appropriate antibiotic treatment.

Ou​​tcome

Treatment includes supportive measures, with voice rest and mucolytics if necessary [1]. Antibiotic treatment is needed in case of bacterial laryngitis, and in cases of Pseudomonas aeruginosa infection, a course of 21 days of ciprofloxacin is a possible treatment strategy [1,3].

Due to the severity of the infection, caused by Pseudomonas aeruginosa, the patient was admitted for treatment with intravenous ciprofloxacin. The immunity panel was normal. Clinical improvement followed, as well as progressive resolution of the imaging findings. Continuation of the treatment with oral ciprofloxacin was needed until complete resolution of the clinical picture.

Take home message / Teaching points

Bacterial laryngitis should be included in the differential diagnosis of patients with prolonged dysphonia.

Imaging is needed if a cause is not identified on clinical examination and laryngoscopy, and should be performed prior to biopsy.

Infectious laryngitis, while in most cases presents as a diffuse thickening and oedema of one or several levels of the larynx, can sometimes mimic a laryngeal tumour.

Nevertheless, in patients with risk factors for developing laryngeal cancer (smoking and alcohol abuse), one should remain cautious in order not to overlook a malignant neoplasm.