Trichomoniasis complicating esophageal intramural pseudodiverticulosis: diagnosis by transmission electron microscopy

A 58-year-old African-American man presented with a progressive esophageal stricture of unknown etiology complicated by esophageal candidiasis, broncho-esophageal fistula, four episodes of aspiration pneumonia, and a 40-lb weight loss. He ultimately required an esophagectomy. Pathologic examination showed marked thickening of the esophageal wall by submucosal pseudodiverticula typical of esophageal intramural pseudodiverticulosis (EIPD) and extensive mucosal and submucosal chronic inflammation and fibrosis. Small, oval cells with ill-defined nuclei were present in lumens of some pseudodiverticula, light microscopically. Their exact nature could not be determined by light microscopy. The diagnosis of trichomoniasis became apparent only after transmission electron microscopic study of these cells demonstrated characteristic features of trichomonad protozoa. These included four anteriorly placed flagella with kinetosomes, a recurrent flagellum associated with an undulating membrane, a costa, a peltar-axostylar complex, and a small Golgi body with parabasal filaments. This case of EIPD is unusual in that the associated broncho-esophageal fistula and trichomoniasis have not been previously reported as complications of EIPD.