A 9-year-old, Staffordshire bull terrier dog, living in Hong Kong, was presented with recurrent gastrointestinal signs. A large ileocaecal–colonic intramural mass and enlarged lymph nodes were found at laparoscopy.
Histopathology of a section of the ileocaecal–colonic mass confirmed the process to be a transmural pyogranulomatous and eosinophilic enteritis with the presence of intralesional fungal hyphae (Fig. 1). The hyphae stained positively with Gomori’s methenamine silver (GMS) (Figs. 2 and 3) and were consistent with fungi from the Oomycetes family.
Fig. 1. Cross-section of colon with extensive thickening of the wall by a pyogranulomatous inflammatory process.
Fig. 2. Gomori’s methenamine silver stain (GMS) stain shows the presence of abundant intralesional fungal hyphae.
Fig. 3. Gomori’s methenamine silver stain (GMS) stain shows fungal hyphae, which are sparsely septate with occasional branching and irregular walls.
1.The histopathology is consistent with what disease(s)?
a. Intestinal pythiosis
b. Intestinal mucormycosis
c. Intestinal entomophthoromycosis
d. Intestinal aspergillosis
2. What technique(s) would enable definitive diagnosis of the disease?
b. Serological tests
c. Histopathology and special stains/immunohistochemistry
Case 3 is written by Dr. Ana R. Resendes