Morphologic identification of mycelial pathogens in tissue sections. A caveat

Lung Infections

A review of pulmonary infections of all types with diagnostic and morphological features.

Fusarium solani infection in a kidney transplant recipient

Hyalo hypho mycosis due to Fusarium species mainly occurs in immunocompromised hosts. The clinical presentation varies from localized to disseminated involvement. A case of localized cutaneous fusariosis caused by Fusarium solani in a renal transplant patient is described and the skin manifestations of the disease are discussed.

Challenges and pitfalls of morphologic identification of fungal infections in histologic and cytologic specimens: a ten-year retrospective review at a single institution

Despite the advantages of providing an early presumptive diagnosis, fungal classification by histopathology can be difficult and may lead to diagnostic error. To assess the accuracy of histologic diagnosis of fungal infections vs culture ("gold standard"), we performed a 10-year retrospective review at our institution. Of the 47 of 338 positive mold and yeast cultures with concurrent surgical pathology evaluation without known history of a fungal infection, 37 (79%) were correctly identified based on morphologic features in histologic and/or cytologic specimens. The 10 discrepant diagnoses (21%) included misidentification of septate and nonseptate hyphal organisms and yeast forms. Errors resulted from morphologic mimics, use of inappropriate terminology, and incomplete knowledge in mycology. The accuracy did not correlate with preceding antifungal therapy (P = .14) or use of special stains (P = .34) and was not operator-dependent. Among 8 discrepancies with clinical follow-up available, 2 potential adverse clinical consequences resulted. While histopathologic identification of fungi in tissue sections and cytologic preparations is prone to error, implementation of a standardized reporting format should improve diagnostic accuracy and prevent adverse outcomes.

Localized cutaneous hyalohyphomycosis caused by a Fusarium species infection in a renal transplant patient

Fusariosis is a hyalohyphomycosis due to Fusarium species that mainly occurs in immunocompromised hosts. The clinical spectrum of Fusarium infection comprises localized and disseminated forms. A case of localized cutaneous fusariosis caused by Fusarium solani in a renal transplant patient is described, and the skin manifestations of the disease are discussed.

Aspergillus aortitis after cardiac surgery

OBJECTIVES

The aim of this study was to describe the clinical characteristics of Aspergillus aortitis in a small series of consecutive patients.

BACKGROUND

Aspergillus infection of the ascending aorta after cardiopulmonary bypass surgery has rarely been reported and has always resulted in death.

METHODS

Aspergillus aortitis was confirmed by pathologic and microbiologic analysis in eight men (61 +/- 8 years) of 9,375 consecutive patients who underwent cardiac surgery between 1975 and 2000.

RESULTS

Patients presented with Aspergillus aortitis after aortic valve replacement (n = 5), coronary revascularization (n = 2), or both (n = 1). Initial symptoms appeared between the immediate postoperative period and up to two years after surgery. All patients had prolonged fever. Ante-mortem diagnosis was established in only three patients for whom transthoracic echocardiography was suggestive of aortic pseudoaneurysm and was confirmed by thoracic computed tomography or aortography. All patients had negative peripheral blood cultures. Seven patients died at short-term follow-up, and the one surviving patient was promptly treated by surgery and antifungal drugs. Pathologic examination confirmed Aspergillus aortitis with multi-organ dissemination without heart involvement in all patients except for two, in whom aortic valve endocarditis was found. Fungal cultures confirmed the presence of Aspergillus fumigatus in all patients.

CONCLUSIONS

Aspergillus aortitis is typically found after aortic valve or coronary surgery. It commonly leads to lethal multi-organ dissemination without involvement of the intracardiac structure. This entity should be considered in patients with persistent fever and negative blood cultures after open-heart surgery involving significant aortic wall damage, irrespective of the postoperative period.