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To determine the prevalence of this histologic feature in pediatric patients, we retrospectively reviewed all cholecystectomy specimens from a pediatric hospital during a 24-month period.
In 180 cholecystectomy specimens, we identified 11 cases (6.1%) with classical histologic features previously described to represent organisms. To further investigate these structures, we retrieved tissue from paraffin-embedded blocks and performed electron microscopy.
Ultrastructural examination identified ovoid perinuclear cytoplasmic structures composed of dense fibrillar aggregates rather than organisms. Patients with positive cases were similar in age to controls (positive cases: mean patient age 13.4 years [range, 2-23 years]; negative cases: mean patient age 14.7 years [range, 12 weeks-31 years]; = .35). There was no significant association of this finding with cholelithiasis (54.5% versus 65.1%, = .52), cholesterolosis (0% versus 22.5%, = .12), acute cholecystitis (9.1% versus 10.1%, > .99), or chronic cholecystitis (45.5% versus 66.3%, = .20).
To our knowledge, this is the first positive identification of these structures as cytoplasmic fibrillar aggregates rather than parasitic inclusions by ultrastructural examination, and the first study of this histologic finding in pediatric cholecystectomies.