Disseminated mucormycosis

Highlights

• •New skin lesions in stem cell transplant recipients warrant a thorough work up.
• •Confirmation of invasive mucormycosis requires a tissue biopsy.
• •Amphotericin B remains the first-line empiric antifungal for mucormycosis.
• •Reconstitution of host immunity is essential for favorable mucormycosis outcomes.

A 59-year-old man was evaluated three weeks after allogeneic hematopoietic stem cell transplantation for myelodysplastic syndrome with neutrophil engraftment by day + 20. Isavuconazole was being administered as mold prophylaxis. Upon initial evaluation, he reported cough, abdominal pain, and a violaceous plaque on the thigh (Fig. 1). Computed tomography identified possible right frontal cerebritis, a right lower lobe consolidation with reverse halo sign (Fig. 2), liver hypodensities, and a large splenic infarct (Fig. 3). Due to concern for an invasive fungal infection, biopsies of the thigh and liver (Fig. 4) lesions were performed and identified invasive aseptate hyphae. A skin tissue culture grew Mucor spp. (Fig. 5). Liposomal amphotericin B was initiated for disseminated mucormycosis. Definitive surgical resection of all foci was prohibited by thrombocytopenia, but he underwent surgical excision of the thigh lesion. After susceptibility testing was performed, posaconazole was added to his anti-fungal regimen. At 4 weeks of follow-up, he was ambulatory and tolerating therapy. Mucormycosis is caused by environmentally ubiquitous molds, and breakthrough mold infection can occur despite appropriate prophylaxis [1], [2]. Risk factors for breakthrough fungal infections include suboptimal antifungal dosing, prolonged neutropenia, mucositis, extended-spectrum antibiotic exposure, and corticosteroid use [1]. Regardless of prophylaxis, clinicians ought to remain vigilant for disease states suggestive of invasive mold infection. Histopathological confirmation of suspected mucormycosis is important to ensure the correct diagnosis and exclude clinical mimics like nocardiosis. In addition to optimizing antifungal therapy, mitigating adverse events, and accounting for drug-drug interactions, reconstitution of host immunity is essential for successful treatment.

Fig. 1.

Cutaneous mucormycosis. A violaceous skin lesion was noted on the anterior thigh. A biopsy demonstrated fungal hyphae in the deep dermis, and tissue culture isolated Mucor spp.

Fig. 2.

Reverse halo sign. Computed tomography imaging of the chest identified the “reverse halo” sign in the right lower lobe. The “reverse halo” sign refers to central ground glass opacification surrounded by a ring of consolidation.

Fig. 3.

Hepatic mucormycosis and splenic infarcts. Computed tomography imaging of the abdomen identified liver lesions suspicious for hepatic involvement from mucormycosis and splenic infarcts. The pneumobilia stemmed from prior choleduodenostomy with stenting.

Fig. 4.

Hepatic mucormycosis. Histopathology of a percutaneous liver biopsy demonstrated vessel invasion and hyphal elements invading liver parenchyma. The photomicrograph demonstrates a representative section at 10X magnification prepared with Grocott-Gomori methenamine silver stain.

Fig. 5.

Mucor spp. Lactophenol cotton blue staining of the mold colony identified wide, non-septate hyphae with right-angle branching morphologically consistent with species from the genus Mucor.

Funding sources

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Agreement

The authors have reviewed the relevant terms of agreement outlined on the IDCases and Elsevier website pages. We stand in agreement with the policies enumerated on the available website pages and completed the declarations form. All authors contributed significantly to the present submission and have approved the submission materials. Thank you for your consideration.

CRediT authorship contribution statement

Elizabeth E Tremblay: Conceptualization, Data curation, Writing – review & editing. Machiavello Roman Francisco Javier: Conceptualization, Supervision, Writing – review & editing. Radcliffe Christopher Vincent: Conceptualization, Writing – original draft.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.