Microbiology Case Study: Elderly woman with Ear Pain

An elderly woman with a past medical history significant for end-stage renal disease status post deceased donor kidney transplant in 2018 (on immunosuppression), type 2 diabetes mellitus, and recurrent urinary tract infections presented to nephrology clinic with right ear pain and rash of three weeks. She was otherwise in her usual state of health. On physical exam, there were exophytic itchy papules with hemorrhagic crust and ulcerations on the ear (Image 1) and arm. A few of these papules showed central umbilication (Image 2). Erosions were also present on the upper back, face, neck, and forearms. Patient was referred to dermatology with concern for disseminated infection versus neoplasia. Complete blood count showed mildly elevated white cells. Serologies, cultures, imaging, lumbar puncture, and biopsy were performed.

Blood studies revealed a Cryptococcus antigen titer of 1:4096 along with a CSF antigen titer of 1:2048. Additionally, the CSF gram stain demonstrated yeast and cultures grew Cryptococcus neoformans. Opening pressure was normal and protein was slightly elevated to 53 mg/mL with 36 nucleated cells with a differential including 64% lymphocytes. Biopsy culture of the left cheek was positive for C. neoformans and a left forearm biopsy showed nodular aggregates of encapsulated yeasts, surrounded by relatively sparse lymphohistiocytic inflammation (Images 3-4). A CT of the chest showed innumerable pulmonary nodules concerning for infection.

Discussion

Cryptococcus is an encapsulated basidiomycetous fungus typically found in soil and pigeon droppings.¹ Two species comprise the majority of Cryptococcus infections: C. neoformans and C. gatti. C. neoformans is most commonly seen in immunosuppressed patients, particularly in the setting of AIDS.² C. gatti infections may be seen in more immunocompetent patients and appears to be more geographically restricted to the tropics and Pacific Northwest.³ C. neoformans infections can present as lung disease associated with symptoms of fever, shortness of breath, or cough and characteristically may spread to the central nervous system to cause meningitis.⁴ Lumbar puncture may show significantly elevated opening pressures.⁵ Other features of disseminated Cryptococcus infections include rash, endocarditis, ocular lesions, or multiorgan failure.⁶

This case is a somewhat unusual presentation of disseminated Cryptococcus infection characterized only by skin findings without clinical features of pulmonary or CNS infection. Approximately 15% of patients with disseminated infection may show cutaneous findings but primary cutaneous cryptococcosis is rare.⁷ Cryptococcal skin findings are quite varied, but may present similar to molluscum contagiosum, as dome shaped papules with central umbilication.^7,8 On microscopy, small variably sized round yeasts without hyphae are characteristic. These yeasts may show a clear or pale staining halo representing the capsule and are highlighted well on Grocott’s Methenamine Silver or Periodic Acid-Schiff stains. Histology may demonstrate innumerable extracellular yeasts accompanied by foamy stroma and minimal inflammation or more granulomatous tissue reaction with necrosis, ulceration, and mixed inflammation. In conclusion, disseminated Cryptococcus must be considered in the context of new skin findings in an immunocompromised patient even if typical pulmonary or CNS findings are not identified.

References

1. Sorrell TC, Ellis DH. Ecology of Cryptococcus neoformans. Rev Iberoam Micol. 1997 Jun;14(2):42-3.
2. Bratton EW, El Husseini N, Chastain CA, Lee MS, Poole C, Sturmer T, et al. Comparison and temporal trends of three groups with cryptococcosis: HIV-infected, solid organ transplant, and HIV-negative/non-transplant. PloS One. 2012;7(8):e43582
3. MacDougall L, Fyfe M, Romney M, Starr M, Galanis E. Risk factors for Cryptococcus gattii infection, British Columbia, Canada. Emerg Infect Dis. 2011 Feb;17(2):193-9.
4. Sabiiti W, May RC. Mechanisms of infection by the human fungal pathogen Cryptococcus neoformans. Future microbiol. 2012 Nov;7(11):1297-313.
5. Abassi M, Boulware DR, Rhein J. Cryptococcal Meningitis: Diagnosis and Management Update. Curr Trop Med Rep. 2015;2(2):90–99. doi:10.1007/s40475-015-0046-y
6. Clark RA, Greer D, Atkinson W, Valainis GT, Hyslop N. Spectrum of Cryptococcus neoformans infection in 68 patients infected with human immunodeficiency virus. Rev Infect Dis. 1990 Sep-Oct;12(5):768-77.
7. Srivastava GN, Tilak R, Yadav J, Bansal M. Cutaneous Cryptococcus: marker for disseminated infection. BMJ Case Rep. 2015;2015:bcr2015210898. Published 2015 Jul 21. doi:10.1136/bcr-2015-210898
8. Akram SM, Koirala J. Cutaneous Cryptococcus (Cryptococcosis) [Updated 2019 Aug 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448148/

-Dr. Stanton Miller is a second year AP/CP resident at UT Southwestern Medical Center who is interested in Dermatopathology.

-Dr. IJ Frame is a board-certified Clinical Pathologist who is completing his Medical Microbiology fellowship at UT Southwestern Medical Center.

-Dr. Dominick Cavuoti is a professor of AP and CP at UT Southwestern, specializing in infectious disease pathology, cytology and medical microbiology.

-Clare McCormick-Baw, MD, PhD is an Assistant Professor of Clinical Microbiology at UT Southwestern in Dallas, Texas. She has a passion for teaching about laboratory medicine in general and the best uses of the microbiology lab in particular.