Isolated tracheal mucormycosis in diabetes mellitus and bronchoscopic management

Dear Editor, We read the interesting case report on airway mucormycosis by Kaliya et al.[1] and the accompanying literature review. Isolated tracheal or airway mucormycosis is indeed an uncommon entity. However, several cases,[2] including a recent systematic review on the topic, have been missed.[3] Thus, the search strategy employed by the authors is unclear. While the authors discuss surgery and anti-fungal therapy in managing isolated tracheobronchial mucormycosis (ITBM), bronchoscopic management was not highlighted. Notably, nearly 30% of subjects with ITBM may require therapeutic bronchoscopy.[3] We illustrate the role of bronchoscopy by describing a case of critical central airway obstruction due to ITBM requiring airway stenting. A 49-year-old man presented with fever, productive cough, and noisy breathing developing over 10 days. He denied haemoptysis, facial swelling, or trauma. There was no recent hospitalization or endotracheal intubation. He had no history of smoking or substance abuse. The physical examination was unremarkable except for stridor at rest. There was a history of poorly controlled diabetes, with glycated haemoglobin of 10.9% at admission. Complete blood count, renal, and liver function tests were normal. Computed tomography of the thorax [Figure 1] showed a polypoidal enhancing soft tissue lesion arising from the lateral tracheal wall along with an endoluminal component. The patient's stridor worsened, and he required endotracheal intubation. Bronchoscopy showed fleshy yellowish-grey material arising from the lower end of trachea, extending 1 cm above the carina [Figure 2a]. The distal tracheobronchial tree was normal. We performed a rigid bronchoscopy under general anaesthesia, and the fleshy, unhealthy material was removed with difficulty using rigid bronchoscopic forceps [Supplemental Video 1] and an electrocautery snare. Once the blackish necrotic content was cleared from the trachea, the underlying trachea appeared unhealthy, and we deployed a covered self-expanding metallic Y-stent [Figure 2b]. The histopathology of the necrotic material and biopsy specimens revealed invasive mucormycosis [Figure 3]. Culture grew Rhizopus arrhizus. He had symptomatic relief after the procedure and was successfully liberated from the ventilator in 24 hours. After initial management with intravenous liposomal amphotericin B (5 mg/kg/day for 12 days), maintenance therapy with posaconazole was continued for 2 months. The metallic stent was removed, and the patient is doing well after 1 year of follow-up.Figure 1: Contrast-enhanced computed tomography images showing polypoidal enhancing soft tissue lesion (mediastinal window, a) arising from the right wall of the trachea with the endoluminal and exophytic components. Air focus interspersed in the tissue and narrowing of the tracheal lumen are also noted. Lung window sections (b) show the same finding (white arrows) with a small subpleural nodule in the right upper lobe (black arrow)Figure 2: Bronchoscopy showing: a. fleshy yellowish-grey material arising from the lower end of trachea and the arrowhead demonstrates underlying unhealthy lateral tracheal wall, and b shows the lower trachea, carina, and bilateral main bronchi after deployment of the covered self-expanding metallic Y-stentFigure 3: a. Photomicrograph of the endobronchial biopsy showing bland tissue necrosis with fungal hyphae; b. High power showing broad aseptate right angle branching fungal hyphae conforming to morphology of mucor {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1","caption":"","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_j166g66q"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Critical airway narrowing due to ITBM is relatively uncommon and challenging to diagnose, requiring a high index of suspicion. In the index case, a tracheal tumour was suspected after the initial presentation and radiology; however, bronchoscopy did not show a tumour. Instead, a fleshy necrotic material from the lateral tracheal wall was seen, suggesting a possible non-malignant aetiology for the central airway obstruction.[4] In immuno-compromised subjects, invasive aspergillosis and mucormycosis can have a similar clinical presentation. Surgery for pulmonary mucormycosis is associated with improved survival.[5,6] However, surgery is not possible in patients with critical central airway narrowing and requires initial rigid bronchoscopy, as in the index case. Therapeutic bronchoscopy, including rigid bronchoscopic mechanical debulking, cryotherapy, argon plasma coagulation, Nd: YAG LASER, snaring, and extraction of mucus plugs, has been performed to relieve luminal obstruction and improve outcomes.[7-14] In ITBM with no respiratory compromise, adjunctive therapies like inhaled or bronchoscopic instillation of amphotericin B can be considered.[15] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.