Monthy Case Studies - 2014
Case #369 - April, 2014
A 24-year-old male with a history of granulomatous immunodeficiency had biopsy specimens taken of skin lesions on his right forearm (Figure A). Specimens were submitted to Pathology for routine histological work-up. Slides were examined by the attending pathologist and images were captured and sent to the DPDx Team for diagnostic assistance. Figures B-E show what was observed by the attending pathologist from the superficial and mid-dermis. Figure B is from a biopsy specimen stained with Gomori methenamine silver (GMS). Figures C and D are from hematoxylin-and-eosin (H&E) stained sections. Figure E is from a section stained with periodic acid-Schiff (PAS). What is your diagnosis? Based on what criteria?
Acknowledgements: This case and images were kindly provided by The University of Michigan Department of Pathology.
Answer to Case #369
This was a case of free-living amebic infection caused by Acanthamoeba sp. Morphologic features shown included:
- the presence cysts that will stain positive for PAS (Figure E) and GMS (Figure B). As such, cysts of Acanthamoeba (and Balamuthia) but be distinguished from fungal elements.
- the presence of cysts (Figures B-E) with a wrinkled outer cyst wall (exocyst) and a spherical inner cyst wall (endocyst).
- the presence of trophozoites (Figure D) with large, centrally-located karyosomes and no peripheral chromatin.
More on: Acanthamoeba infections
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Images presented in the monthly case studies are from specimens submitted for diagnosis or archiving. On rare occasions, clinical histories given may be partly fictitious.