Skin nontumor
Infectious disorders
Algal infection-Prototheca
Author: Nat Pernick, M.D.
Last author update: 1 July 2011
Last staff update: 18 January 2021
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Prototheca
Table of Contents
Definition / general | Case reports | Treatment | Clinical images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Additional referencesCite this page: Pernick N. Algal infection-Prototheca. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorprototheca.html. Accessed April 24th, 2024.
Definition / general
- Not fungi but similar features
- First recognized as human pathogen in 1964; 2 species associated with human disease: P. wickerhamii and P. zopfii
- Aerobic, achlorophyllous, algae-like, unicellular organisms in water, sewage and soil
- < 100 cases of human infection reported, usually via trauma or contaminated water, involving face or exposed extremities with erythematous plaques, nodules or superficial ulcers
- Rarely infects toenails of patients with diabetes (Mycopathologia 2011;172:207)
- Primary cell or spherule is called the theca; species reproduce by internal septation, forming sporangia which contain up to 20 endospores
- P. wickerhamii: cells are rounder than the oval / cylindrical shapes of P. zopfii
- Diagnosis: corn meal agar
Case reports
- 34 year old woman with index finger pain and hobbies of scuba diving and maintaining an aquarium (Arch Pathol Lab Med 2001;125:450)
- 73 year old man with nodules on leg secondary to splinter injury while chopping firewood (Case #225)
Treatment
- Amphotericin B if disseminated, surgical excision if focal cutaneous or subcutaneous
Clinical images
Images hosted on other servers:
Lesion on foot
Microscopic (histologic) description
- Necrotizing granulomas of subcutis containing spherical organisms with central basophilia, internal septation and double layer cell walls
- Also multiple endospores 2 - 4 microns
Microscopic (histologic) images
Images hosted on other servers:
Various images
Internal septation
H&E, GMS and PAS
Additional references
