Paracoccidioidomycosis of the Central Nervous System: CT and MR Imaging Findings

Paracoccidioidomycosis cases by Paracoccidioides lutzii in southeastern Brazil

BACKGROUND AND OBJECTIVE

Paracoccidioidomycosis (PCM) is a systemic fungal disease caused by the thermodimorphic fungi Paracoccidioides spp. Their distribution is highly variable. Paracoccidioides lutzii is predominantly found in North and Middle-West Brazil and Ecuador. This study evaluated the clinicopathological characteristics of 10 patients diagnosed with PCM caused by P. lutzii in a reference center located in southeastern Brazil.

DESIGN

Double immunodiffusion assay (DID) was used to investigate 35 patients' sera with negative serology for P. brasiliensis against a P. lutzii CFA (cell-free antigen).

RESULTS

Out of the 35 retested patients, 10 (28.6%) were positive for P. lutzii CFA. Four patients did not report any displacement to P. lutzii endemic areas. Our results reinforce the importance of using different antigens when testing patients with clinical manifestations of PCM and negative serological tests for P. brasiliensis, primarily in cases of the report of displacement to or former residence in P. lutzii endemic regions.

CONCLUSIONS

The availability of tests for different Paracoccidioides species antigens is fundamental for reaching an adequate diagnosis, patient follow-up, and definition of prognosis.

Insights into Magnetic Resonance Imaging Findings in Central Nervous System Paracoccidioidomycosis: A Comprehensive Review

Paracoccidioidomycosis (PCM) is a infection caused by the thermodimorphic fungus Paracoccidioides spp. (P. lutzii and, mainly, P. brasiliensis). This infection predominantly affects rural male workers aged between 30 and 50 years old who deal with soil on daily activities. Clinically, the disease is classified as acute/subacute phase, which evolves rapidly, secondary to dissemination of the fungus through to the phagocytic-mononuclear system, leading to fever, weight loss, and anorexia, associated with hepatosplenomegaly and lymphadenopathy, which can be complicated with suppuration and fistulization; and chronic phase, which corresponds to 74% to 95% of symptomatic cases, with a common pulmonary involvement. Central nervous system involvement is almost always a characteristic of the chronic form. Inhalation is the most common route of primary infection, usually affecting the lungs, forming the primary complex. From the primary complex, hematogenic dissemination can occur to any organ, including the brain and spinal cord. Although PCM of the central nervous system diagnosis is usually based on histopathological analysis and the imaging features are not specific for PCM, computed tomography and magnetic resonance imaging can demonstrate evidences of granuloma, abscess, meningitis, or a combination of these lesions, contributing to a preoperative diagnosis, especially when considered in conjunction with epidemiology. In this article, we review the pathophysiology, clinical manifestations and imaging aspects of neuro-PCM.

"Star of Bethlehem sign" in the analysis of the evolution of brain lesions during and after treatment for neuroparacoccidioidomycosis

Objective

To describe the clinical and radiological evolution of lesions during and after treatment in patients diagnosed with neuroparacoccidioidomycosis (NPCM).

Materials and Methods

This was a retrospective study of the medical records, computed tomography scans, and magnetic resonance imaging (MRI) scans of patients with NPCM treated between September 2013 and January 2022.

Results

Of 36 cases of NPCM, eight were included in the study. One patient presented only with pachymeningeal and skull involvement, and seven presented with pseudotumors in the brain. Collectively, the eight patients presented with 52 lesions, of which 46 (88.5%) were supratentorial. There were 32 lesions with a diameter ≤ 1.2 cm, of which 27 (84.4%) disappeared during the treatment. In three cases, there were lesions > 1.2 cm that showed a characteristic pattern of evolution on MRI: an eccentric gadolinium contrast-enhanced nodule, with a subsequent decreased in the size and degree of contrast enhancement of the lesions.

Conclusion

In NPCM, supratentorial lesions seem to predominate. Lesions ≤ 1.2 cm tend to disappear completely during treatment. Lesions > 1.2 cm tend to present with a similar pattern, designated the "Star of Bethlehem sign", throughout treatment.

Paracoccidioidomycosis: What We Know and What Is New in Epidemiology, Diagnosis, and Treatment

Paracoccidioidomycosis (PCM) is a systemic mycosis endemic to Latin America caused by thermodimorphic fungi of the genus Paracoccidioides. In the last two decades, enhanced understanding of the phylogenetic species concept and molecular variations has led to changes in this genus’ taxonomic classification. Although the impact of the new species on clinical presentation and treatment remains unclear, they can influence diagnosis when serological methods are employed. Further, although the infection is usually acquired in rural areas, the symptoms may manifest years or decades later when the patient might be living in the city or even in another country outside the endemic region. Brazil accounts for 80% of PCM cases worldwide, and its incidence is rising in the northern part of the country (Amazon region), owing to new settlements and deforestation, whereas it is decreasing in the south, owing to agriculture mechanization and urbanization. Clusters of the acute/subacute form are also emerging in areas with major human intervention and climate change. Advances in diagnostic methods (molecular and immunological techniques and biomarkers) remain scarce, and even the reference center’s diagnostics are based mainly on direct microscopic examination. Classical imaging findings in the lungs include interstitial bilateral infiltrates, and eventually, enlargement or calcification of adrenals and intraparenchymal central nervous system lesions are also present. Besides itraconazole, cotrimoxazole, and amphotericin B, new azoles may be an alternative when the previous ones are not tolerated, although few studies have investigated their use in treating PCM.

The Impact of Paracoccidioides spp Infection on Central Nervous System Cell Junctional Complexes

Paracoccidioidomycosis (PCM), a systemic mycosis caused by the fungus Paracoccidioides spp. is the most prevalent fungal infection among immunocompetent patients in Latin America. The estimated frequency of central nervous system (CNS) involvement among the human immunodeficiency virus (HIV)/PCM-positive population is 2.5%. We aimed to address the impact of neuroparacoccidioidomycosis (NPCM) and HIV/NPCM co-infection on the tight junctions (TJ) and adherens junction (AJ) proteins of the CNS. Four CNS formalin-fixed paraffin-embedded (FFPE) tissue specimens were studied: NPCM, NPCM/HIV co-infection, HIV-positive without opportunistic CNS infection, and normal brain autopsy (negative control). Immunohistochemistry was used to analyze the endothelial cells and astrocytes expressions of TJ markers: claudins (CLDN)-1, -3, -5 and occludin; AJ markers: β-catenin and E-cadherin; and pericyte marker: alpha-smooth muscle actin. FFPE CNS tissue specimens were analyzed using the immunoperoxidase assay. CLDN-5 expression in the capillaries of the HIV/NPCM coinfected tissues (mixed clinical form of PCM) was lower than that in the capillaries of the HIV or NPCM monoinfected (chronic clinical form of PCM) tissues. A marked decrease in CLDN-5 expression and a compensatory increase in CLDN-1 expression in the NPCM/HIV co-infection tissue samples was observed. The authors suggest that Paracoccidioides spp. crosses the blood-brain barrier through paracellular pathway, owing to the alteration in the CLDN expression, or inside the macrophages (Trojan horse).

Neuroparacoccidioidomycosis: A 13-Year Cohort Study, Rio de Janeiro, Brazil

Neuroparacoccidioidomycosis (NPCM) is a rare and severe clinical presentation of paracoccidioidomycosis (PCM). We performed a retrospective cohort study at the Evandro Chagas National Institute of Infectious Diseases (INI/Fiocruz), a reference center for PCM in the state of Rio de Janeiro, Brazil. All cases of PCM admitted to the INI/Fiocruz from January 2007 to December 2019 were reviewed. Eight (3.9%) among 207 patients met the diagnostic criteria for NPCM. The mean age was 44.6 years and the male:female ratio was 7:1. All cases presented multifocal disease, 5 (62.5%) the chronic form and 3 (37.5%) the acute/subacute form. All patients presented the pseudotumoral pattern and 6 (75.0%) had multiple lesions in the cerebral hemispheres. Seizures and motor symptoms were the most frequent clinical manifestations (50.0%, each). The treatment of choice was sulfamethoxazole/trimethoprim (SMZ-TMP) and fluconazole, in association (87.5%). Most patients responded well to the treatment. Sequela and death occurred in one (12.5%) patient, each.

Delayed Relapse of Paracoccidioidomycosis in the Central Nervous System: A Case Report

Paracoccidioidomycosis is a dimorphic fungal infection endemic in Latin America. We report a patient with a history of pulmonary paracoccidioidomycosis who presented with relapsed disease in the central nervous system 4 years after initial treatment. We review current treatment strategies for paracoccidioidomycosis and neuroparacoccidioidomycosis.