Granulomatous Skin Disease After Exotic Injury

Overview

Piranhas are feared freshwater fishes commonly found in the waters of southern Venezuela to thenorth of Argentina. At present this species is a favourite domesticated article of our aquarists.The authors describe the histopathologic picture of a cutaneous lesion of the right hand thumb ofa 60-year old piranha keeper who was bitten by this predatory fish. A firm node with increasingsoreness gradually developed in the area of the lesion, and after 7 months the symptoms of thecarpal tunnel syndrome were also present. Granulomatous foci – some sarcoid-like, others withcentral necrosis – were permeated with fibrinoid substance. Epithelioid granuloma cells withhuge incorporated multinuclear elements were covered mainly by T-lymphocytes. Ziehl-Neelsenstain did not prove the presence of diagnostic acid-fast rods. Only in some macrophages rareacid-fast spheric microstructures were present in the cytoplasm. Both the local dermatologicfinding and histological examination gave evidence that the skin was infected with atypicalmycobacteria – swimming pool granuloma.

Key words:
piranha injury – granulomatous inflammation – swimming pool granuloma – atypicalmycobacteriosis