Year: 2024
Type: article
Study design: Case Report
Abstract: A 48-year-old woman who received a living-unrelated kidney transplant 5 years ago due to end-stage renal disease caused by lupus nephropathy is currently on a maintenance immunosuppression regimen that includes tacrolimus, mycophenolate mofetil, and low-dose prednisone. She presents with progressive hoarseness that has persisted for 3 months, accompanied by an intermittent dry cough, without any preceding symptoms or associated constitutional symptoms. Flexible laryngoscopy revealed submucosal nodules at the anterior commissure and extending along the medial and superior aspects of the anterior third of both true vocal cords (Figure 1A). The nodules did not visibly extend into either the supraglottis or the subglottis. Histopathologic findings showed significant granulomatous inflammation in the submucosa (Figure 1B). Acid-fast stain showed numerous acid-fast microorganisms (Figure 1C). Tissue culture of the vocal cord identified Mycobacterium avium Complex (Mycobacterium avium). No organism was recovered from blood cultures. The patient was initiated on triple therapy with azithromycin, rifabutin, and ethambutol. Serial laryngoscopies demonstrated improvement in vocal cord nodules (Figure 1D). The current plan is to continue antimycobacterial treatment for at least 12 months. (A) Submucosal nodules at the anterior commissure and along the medial and superior aspect of the anterior 1/3 of bilateral true vocal cords (white arrow). (B) H&E stain revealed benign squamous mucosa with marked granulomatous inflammation in the submucosa (black asterisk). (C) Acid-fast staining reveals numerous acid-fast microorganisms. (D) The vocal cord nodule (yellow arrowhead) was improved during antimycobacterial treatment (third month of therapy). In regions where tuberculosis is not endemic, infections caused by non-tuberculous mycobacteria (NTM) are more prevalent than tuberculosis among solid organ transplant (SOT) recipients.1 The incidence of NTM infection is higher in lung transplant recipients than in non-lung SOT transplant recipients.2 Additionally, NTM infections are more likely to affect the lungs than other body parts.2,M. abscessus is the most frequently isolated species from lung transplant recipients, while the Mycobacterium avium complex (MAC) is the most commonly isolated species in non-lung SOT recipients.2 Although NTM infection of the respiratory tract is not rare, laryngeal NTM infection has been reported in fewer than 10 cases, including species such as M. abscessus, MAC, M. fortuitum, M. malmoense, and M. kansasii.3–5 Laryngoscopy typically reveals mass-like lesions, but ulcerative lesions have also been reported.6 Predominantly, patients with laryngeal NTM infection showed no signs of pulmonary involvement and did not progress to disseminated NTM disease.3 NTM species are ubiquitous environmental organisms; person-to-person transmission is not observed.2 Therefore, direct inoculation from environmental exposure is the most plausible explanation for laryngeal NTM infections in reported cases and our patient. Despite limited knowledge about the specific treatment of laryngeal NTM infections, the regimen of antimycobacterial treatments remains consistent with those used for pulmonary NTM, but the treatment duration for laryngeal NTM infections varies widely (from 17 weeks to 12 months).3 This variation is attributed to factors such as the Mycobacterium species, the extent of vocal cord damage, the patient's response to treatment, and their ability to tolerate the treatment.3 Another challenge in treating NTM infections in SOT recipients is the potential for drug-drug interactions between antimycobacterial medications and immunosuppressive agents. Beyond antimycobacterial therapy, a small number of patients also required surgical intervention, such as mass debridement or vocal cord dilation, to address severe invasive disease or to manage fibrotic scar formation.5,6 Chia-Yu Chiu (Conceptualization [equal], Formal analysis [equal], Investigation [equal], Writing—original draft [equal], Writing—review & editing [equal]), Semirra L. Bayan (Data curation [supporting], Writing—review & editing [equal]), Eunhee S. Yi (Data curation [supporting], Writing—review & editing [equal]), and Nathan W. Cummins (Conceptualization [equal], Supervision [lead], Writing—review & editing [equal]) All authors declare that they have no conflicts of interest. Case details have been anonymized, and the patient has consented to the publication of this case and clinical images.
Source: QJM
Authors: C -Y Chiu, S L Bayan, E S Yi, N W Cummins
Institution: Mayo Clinic
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4396626115