eMedicine Specialties > Dermatology > Parasitic Infections

Protothecosis, Cutaneous: Differential Diagnoses & Workup

Author: Sarah K Taylor, MD, Staff Physician, Department of Dermatology, Walter Reed Army Medical Center and National Naval Medical Center
Coauthor(s): Jon H Meyerle, MD, Assistant Professor, Department of Dermatology, Johns Hopkins University School of Medicine; Consulting Staff, Laboratory Director, Department of Dermatology, Walter Reed Army Medical Center and National Naval Medical Center; Earl J Glusac, MD, Professor, Departments of Pathology and Dermatology, Yale University School of Medicine
Contributor Information and Disclosures

Updated: Dec 11, 2008

Differential Diagnoses

Atypical Mycobacterial Diseases
Chromoblastomycosis
Pyoderma Gangrenosum
Tinea Corporis

Other Problems to Be Considered

Blastomycosislike pyoderma
Deep fungal infection

Workup

Laboratory Studies

  • A diagnosis of protothecosis can be made based on findings from either biopsy or culture.
    • Prototheca species readily grow on Sabouraud glucose agar. Smooth, white-to-beige colonies typically demonstrate growth within 48 hours at room temperature.
    • Prototheca species may also be cultured on blood agar, heart-brain infusion agar, or beef infusion broth.
    • Commercial assays that rely on the unique components of the cell wall are also available for identification of Prototheca species.

Other Tests

  • No other tests are necessary; however, electron microscopy reveals a double-layered cell wall without chloroplasts. These features differentiate Prototheca organisms from other types of algae.

Histologic Findings

Protothecosis demonstrates morula formation. Typically, the organisms are 6-10 µm in diameter either outside of the macrophages or within the macrophages. They are best visualized with special stains (eg, periodic acid-Schiff, Gomori methenamine-silver) that are used to highlight fungi. The diagnostic feature of P wickerhamii is the presence of sporangia with a central rounded endospore surrounded by a corona of molded endospores. The appearance of the sporangia is diagnostic, and it is described as moruloid, daisylike, spokelike, and frambesiform.

The principal histopathologic differential diagnosis is coccidioidomycosis, which often shows larger sporangia and always shows smaller endospores (2-4 µm).

More on Protothecosis, Cutaneous

Overview: Protothecosis, Cutaneous
Differential Diagnoses & Workup: Protothecosis, Cutaneous
Treatment & Medication: Protothecosis, Cutaneous
Follow-up: Protothecosis, Cutaneous
Multimedia: Protothecosis, Cutaneous
References
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References

  1. Walsh SV, Johnson RA, Tahan SR. Protothecosis: an unusual cause of chronic subcutaneous and soft tissue infection. Am J Dermatopathol. Aug 1998;20(4):379-82. [Medline].

  2. Lass-Florl C, Mayr A. Human protothecosis. Clin Microbiol Rev. Apr 2007;20(2):230-42. [Medline].

  3. Lee JS, Moon GH, Lee NY, Peck KR. Case report: Protothecal tenosynovitis. Clin Orthop Relat Res. Dec 2008;466(12):3143-6. [Medline].

  4. Khoury JA, Dubberke ER, Devine SM. Fatal case of protothecosis in a hematopoietic stem cell transplant recipient after infliximab treatment for graft-versus-host disease. Blood. Nov 15 2004;104(10):3414-5. [Medline].

  5. Torres HA, Bodey GP, Tarrand JJ, Kontoyiannis DP. Protothecosis in patients with cancer: case series and literature review. Clin Microbiol Infect. Aug 2003;9(8):786-92. [Medline].

  6. Carey WP, Kaykova Y, Bandres JC, Sidhu GS, Brau N. Cutaneous protothecosis in a patient with AIDS and a severe functional neutrophil defect: successful therapy with amphotericin B. Clin Infect Dis. Nov 1997;25(5):1265-6. [Medline].

  7. Polk P, Sanders DY. Cutaneous protothecosis in association with the acquired immunodeficiency syndrome. South Med J. Aug 1997;90(8):831-2. [Medline].

  8. Boyd AS, Langley M, King LE Jr. Cutaneous manifestations of Prototheca infections. J Am Acad Dermatol. May 1995;32(5 Pt 1):758-64. [Medline].

  9. Kantrow SM, Boyd AS. Protothecosis. Dermatol Clin. Apr 2003;21(2):249-55. [Medline].

  10. Zaitz C, Godoy AM, Colucci FM, de Sousa VM, Ruiz LR, Masada AS, et al. Cutaneous protothecosis: report of a third Brazilian case. Int J Dermatol. Feb 2006;45(2):124-6. [Medline].

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Further Reading

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Keywords

Prototheca, Prototheca wickerhamii, P wickerhamii, Prototheca zopfii, P zopfii, cutaneous protothecosis

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Contributor Information and Disclosures

Author

Sarah K Taylor, MD, Staff Physician, Department of Dermatology, Walter Reed Army Medical Center and National Naval Medical Center
Disclosure: Nothing to disclose.

Coauthor(s)

Jon H Meyerle, MD, Assistant Professor, Department of Dermatology, Johns Hopkins University School of Medicine; Consulting Staff, Laboratory Director, Department of Dermatology, Walter Reed Army Medical Center and National Naval Medical Center
Jon H Meyerle, MD is a member of the following medical societies: American Academy of Dermatology and Sigma Xi
Disclosure: Nothing to disclose.

Earl J Glusac, MD, Professor, Departments of Pathology and Dermatology, Yale University School of Medicine
Earl J Glusac, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Medical Editor

Barbara R Reed, MD, Clinical Professor, Department of Dermatology, Dermatology Service, Denver Veterans Affairs Medical Center, University of Colorado Health Sciences Center; Consulting Staff, Denver Skin Clinic
Disclosure: Nothing to disclose.

Pharmacy Editor

David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Chair, Department of Dermatology, Director, Dermatology Residency Training Program, Scott and White Clinic
David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Association of Military Dermatologists, and Phi Beta Kappa
Disclosure: 3M Pharmaceutical Grant/research funds Other; Graceway Pharmaceuticals Grant/research funds Other

Managing Editor

Christen M Mowad, MD, Associate Professor, Department of Dermatology, Geisinger Medical Center
Christen M Mowad, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, and Phi Beta Kappa
Disclosure: Nothing to disclose.

CME Editor

Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University
Catherine Quirk, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 
 
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