Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Mucormycosis
- Radiologic Findings
- Fig 1. CT scan when he complained of febrile sensation revealed a focal area of consolidation with surrounding GGO in left lingular segment.
Fig 2-4. CT scans were obtained 19 days after figure 1. Chest CT with contrast enhancement was performed with coronal reconstructive images. The CT scans demonstrated central GGOs with a surrounding irregular rim of consolidation (reversed halo sign) in left lingular segment. This lesion has extended to the visceral pleura that is resulting in pleural thickening.
- Brief Review
- Mucormycosis is an opportunistic fungal infection and it is caused by fungi of the order Mucorales in the class Zygomycetes. Mucormycosis is far less common than other opportunistic fungal infections including Aspergillus and Candida infections, although the mortality rate is much higher.
Infection is usually caused by inhalation of spores and the paranasal sinuses and lungs are most commonly affected. Pulmonary infection causes cough, fever, hemoptysis, and pleuritic chest pain.
Risk factors for mucormycosis infection include diabetes, hematologic malignancy, stem cell or solid organ transplantations, immunosuppression, graft-versus-host disease, and desferoxamine therapy. At the time of diagnosis, only just under half of patients show neutropenic condition.
Clinical diagnosis of mucomycosis is challenging because the clinical features overlap with those of other infections and because of the lack of blood marker such as galactomannan and β-d-glucan. Definitive diagnosis often needs invasive sampling, which may delay treatment and is not always successful. Therefore, radiologic findings can play an important role in the diagnosis.
Imaging findings are mostly nonspecific and include consolidation, nodules, masses, cavities, lymphadenopathy, and pleural effusion. Suggestive findings of invasive fungal infection include air crescent sign (a thin rim of air between the necrotic lung and the surrounding parenchyma) and the halo (consolidation with a rim of surrounding GGO, 53%). Mucormycosis is an aggressive angio-invasive infection that often leads to pulmonary infarction (more extensive and more rapid than Aspergillus infection). Mucormycosis can demonstrate as the “reverse halo” (or “reversed halo”) sign on CT, which describes a consolidation with central ground-glass (60-67%). In addition, the lesions commonly present the peripheral distribution (87%). According to Wahba et al., in immunocompromised patients, despite the lower prevalence of the reverse halo sign, it could be more predictive of mucormycosis than invasive pulmonary aspergillosis. Nam et al. suggested initial CT scans of patients with mucormycosis commonly demonstrate consolidation or nodule/mass with halo sign, when patients had treatment and recovery of neutropenia, the majority of patients demonstrated sequential morphologic changes such as revere halo sign, central necrosis and air crescent sign, as similar features of invasive pulmonary aspergillosis.
Treatment for mucormycosis depends on antifungal agents, surgery, and control of predisposing conditions. Amphotericin B and, more recently, posaconazole are efficacious in the treatment of mucormycosis. Voriconazole is not effective although it is effective in the treatment of aspergillosis.
- Please refer to
Case 223, Case 270, Case 411, Case 559, Case 714, Case 720, Case 735, Case 990, Case 1103, Case 1110, -
KSTR Imaging Conference 2006 Spring Case 6
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KSTR imaging conference 2017 Spring Case 11
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KSTR imaging conference 2018 Spring Case 9,
- References
- 1. Hammer MM, Madan R, Hatabu H. Pulmonary mucormycosis: Radiologic features at presentation and over time. AJR 2018; 210:742–747
2. Chung JH, Godwin JD, Chien JW, Pipavath SJ. Case160: Pulmonary Mucormycosis. Radiology 2010; 256:667-670
3. Legouge C, Caillot D, Chrétien ML, Lafon I, Ferrant E, Audia S, Pagès PB. The reversed halo sign: pathognomonic pattern of pulmonary mucormycosis in leukemic patients with neutropenia? Clin Infect Dis. 2014;58:672-678
4. Wahba H, Truong MT, Lei X, Kontoyiannis DP, Marom EM. Reversed halo sign in invasive pulmonary fungal infections. Clin infect Dis. 2008;46:1733-1737
5. Nam BD, Kim TJ, Lee KS, Kim TS, Han J, Chung MJ. Pulmonary mucormycosis: serial morphologic changes on computed tomography correlate with clinical and pathologic findings. Eur Radiol 2018;28:788-795
- Keywords
- lung, fungal infection, mucormycosis,