Cestodiasis with intestinal diverticulosis in a lesser flamingo (Phoeniconaias minor).

An adult female lesser flamingo (Phoeniconaias minor), caught in the African Rift Valley in 1991 and subsequently housed at the Baltimore Zoo, died of severe visceral gout in 1996. Necropsy revealed a white, moderately firm, nodular lesion, 1 cm in diameter, in the serosal wall of the small intestine. Although it was initially thought to be a tumor or focal granuloma, histologic examination revealed multiple cestodes deeply embedded at the base of the crypts between the intestinal villi, with their massive scolices (up to 3.4 mm in diameter) distending these spaces into multiple diverticulae. The mucosal epithelium surrounding the scolices was severely attenuated. Around the diverticulae, in the submucosa and muscularis, was a mild to moderate lymphocytic reaction and mild fibrosis. The proximity of multiple scolices and extensive invasion of host tissue suggested that the infection occupied a preexisting lesion. The cestodes were cyclophyllids but were distinct from any species previously reported from flamingos. Helminths should be included in differential diagnoses for gastrointestinal nodules in flamingos.

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.