Aim: To reported extremely rare case of collision adenocarcinomma et small cell neuroendocrine carcinomma of the gallbladder (SCNEC). Introduction: Collision cancers are malignancies in the same organ or anatomical site that comprises et least two different tumor components, with no mixed or transitional area between two component. Case report: 76 year old woman with abdominal pain, underwent ultrasonography evaluation which demonstrated cholelithiasis and gallbladder wall thickening. Cholecystectomy due to cholelithiasis was performed.The macroscopic analysis revealed 2,5cm sized round nodular lesions in the fundus of the gallbladder.Formalin fixed, paraffin embedded tissues were stained with H.E. Selected samples were stained immunochistochemically with chromogranin, synaptophysin et CK7. Microscopicaly, the tumor was composed of two components. Dominant component is adenocarcinomma, composed of tubular glands lined predominantly by columnar cells with pseudostratified et ovoid or elongated nuclei.In the area close to this component there was neuroendocrine carcinomma that came in touch with the previous one, but didnt infiltrate it. Neuroendocrine carcinomma was composed of round or fusiform cells, arranged in sheets, nests and cords.Tumor cells have round hyperchromatic nuclei with inconspicuous nucleoli. Neuroendocrine tumor cells were immunoreactive for chromogranin, synaptophysin. Epithelial cells were positive for CH7.The final pathologycal diagnosis was SCNEC. The tumor stage was II, T2, Nx, Mx. Conclusion: Prognosis for patient is poor.About 40-50 percent of patients have disseminated disease at the time of the diagnoses.SCNEC appear to be highly responsive to chemotherapy as well as radiotherapy and survival time more than one year have been reported.

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