Lymphoid follicules fill the lamina propria while there is no significant inflammation in the deeper layers of the gallbladder wall.
No significant inflammation deep to lamina propria again, but note the well formed lymphoid aggregates expanding the lamina propria.
Follicular cholecystitis is a variant of chronic cholecystitis characterized by the widespread presence of lymphoid follicles in all layers of the gallbladder wall, but especially in the lamina propria (Rosai). Key features of chronic cholecystitis such as muscular hypertrophy, mural fibrosis and Rokitansky-Aschoff sinuses may also been seen.
Not much is known about this variant. The surgical pathology texts do not describe this variant well, and there is no literature in PubMed discussing this entity. Note that other variants of cholecystitis include diffuse lymphoplasmacytic cholecystitis (seen in primary sclerosing cholangitis), eosinophilic cholecystitis and xanthogranulomatous cholecystitis (granulomatous reaction from rupture of Rokitansky-Aschoff sinuses) (Rosai, Iacobuzio).
Iacobuzio-Donahue CA, Montgomery EA. Gastrointestinal and Liver Pathology: Foundations in Diagnostic Pathology. Philadelphia, PA: Elsevier; 2005: 439.
Rosai, J. Rosai and Ackerman's Surgical Pathology. 9th Ed. Philadelphia, PA: Elsevier; 2004: 1042.