[Colo-rectal spirochetosis: is it an anatomo-pathologic entity?].

Area of Science:

• Gastroenterology
• Histopathology
• Microbiology

Context:

• Colorectal spirochetosis is a condition characterized by the presence of spirochetes in the colon.
• The typical histologic finding is a thickened, blue, and fuzzy brush border on Hematein-Eosin-Safran (HES) stained biopsy specimens.
• This feature has been observed in patients with chronic diarrhea, those without intestinal symptoms, and those with colonic tumors.

Purpose:

• To evaluate the diagnostic significance of the thickened brush border in colorectal biopsies.
• To determine if this histologic feature is specific for colorectal spirochetosis.
• To assess the prevalence of spirochetes in HIV-negative males and HIV-1 seropositive individuals.

Summary:

• Nineteen male colorectal biopsy specimens exhibited a thick, blue, and fuzzy brush border on HES stain.
• While suggestive, this finding was not specific for colorectal spirochetosis, as confirmed by Warthin-Starry silver stain in only three cases.
• A control group of 35 HIV-1 seropositive patients showed a similar brush border thickening in one case, but no spirochetes were identified.
• The study highlights that silver staining is essential for confirming the presence of spirochetes.

Impact:

• The findings emphasize that the thickened brush border is not a definitive diagnostic criterion for colorectal spirochetosis.
• Pathologists must be aware of this potential pitfall and utilize silver stains for confirmation.
• Further research is needed to elucidate the pathogenicity of colorectal spirochetosis.