case report

Unsuspected Dematiaceous Fungal Infection Causing Subcutaneous Nodules in a Diabetic Patient

Lauren Fontana1, Marcel E. Curlin2*

1Division of Infectious Diseases, University of Minnesota, Minneapolis, MN, USA

2Department of Medicine, Division of Infectious Diseases, Oregon Health and Science University, Portland, USA

*Corresponding author: Marcel E. Curlin, Department of Medicine, Division of Infectious Diseases, Oregon Health and Science University, Portland, USA

Received Date: 29 September 2022

Accepted Date: 03 October 2022

Published Date: 05 October 2022

Citation: Fontana L, Curlin ME (2022) Unsuspected Dematiaceous Fungal Infection Causing Subcutaneous Nodules in a Diabetic Patient. Ann Case Report 7: 976. DOI: https://doi.org/10.29011/2574-7754.100976

Abstract

Melanised dematiaceous fungi are environmental saprophytes that can cause subcutaneous phaeohyphomyosis. We describe a case of coincident subcutaneous phaeohypomycosis due to Medicopsis romero and Cryptococcus neoformans meningitis in a Cambodian native female with uncontrolled diabetes mellitus and seropositive non-erosive rheumatoid arthritis receiving chronic steroids. Both organisms are dematiaceous environmental fungi but M. Romero infrequently causes invasive disease, occurring most commonly in the setting of immune suppression. We discuss the clinical significance, diagnosis and treatment of phaeohyphomycosis in an immunocompromised host.

Case Report

A 65 y/o Cambodian native female, who immigrated to the United States 30 years ago, presented with an 18-month history of persistent painless right knee swelling, and six days of acute fever and progressive confusion. Her medical history included poorly controlled type II diabetes mellitus, and seropositive rheumatoid arthritis (RA) diagnosed two years prior to admission. On initial rheumatologic evaluation, she was prescribed oral methotrexate 15mg weekly for 11 months and prednisone 10mg daily. The prednisone dose was increased to 20mg for ongoing generalized arthralgia one year later. However, ten months after starting therapy, she developed persistent painless right knee swelling, and eight months later experienced new spontaneous drainage from a nodular lesion overlying the patella. A home remedy of vinegarsoaked bread was applied but swelling and drainage persisted. Admission vital signs revealed a fever of 103oC, HR of 110 bpm, BP of 85/51 mmHg, and oxygen saturation of 88% on room air. Examination confirmed confusion without focal neurologic deficits. The right knee was swollen with multiple fluctuant prepatellar lesions (Figure 1, panel A) from which abundant cream-colored pus was expressed. The serum WBC count was 12 K/mm. Lumbar puncture opening pressure was 22 cm H2O. Cerebral spinal fluid (CSF) contained 32 WBC with 87% lymphocytes, protein and glucose values of 263mg/dL and 135mg/dL, respectively. CSF Cryptococcus antigen was positive (titer 1:320) and fungal culture grew Cryptococcus neoformans. Testing for HIV and tuberculosis was negative.

Manually expressed knee drainage revealed 3+ fungal spectated pseudo hyphae (Figure 1, panels D, E). Right knee MRI revealed multiple subcutaneous rim-enhancing prepatellar collections but no knee joint abnormalities (Figure 1, panels B, C). Pathology from a prepatellar bursectomy demonstrated an organizing abscess with surrounding fibrosis, and multinucleated histiocytic. No macroscopic granules were observed. Groote’s methoxamine silver stain showed darkly pigmented spores and hyphae within inflammatory zones (Figure 1, panel F). Mucicarmine stain was negative for Cryptococcus. Surgical culture revealed fungal hyphae and sequencing of 28S ribosomal DNA yielded a final diagnosis of Medicopsis romero. The patient’s hospital course was complicated by prolonged encephalopathy due to Cryptococcal meningitis requiring serial lumbar punctures. She received liposomal amphotericin and flu cytosine for 28 days, followed by consolidation therapy with voriconazole and was ultimately discharged in stable condition.