These included one patient in whom the diagnosis was made only after the initial cholecystectomy specimen was reviewed four years later when he presented with bowel obstructive symptoms due to peritoneal carcinomatosis, one patient in whom surface dysplasia involving Rokitansky-Aschoff sinuses (RAS) and adenomyosis was mistaken for deeply invasive carcinoma, one patient in whom geographic tumoral necrosis closely resembled acute gangrenous necrosis more typical in acute cholecystitis, and one patient with isolated mucin pools and only rare tumor cells. The gene discussed is MUC5AC; the disease is neoplasm.