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.

Aim: Immunohistochemistry findings along with clinical features, are significantly important in differentiating the Extrapleural SFT in the neck, from other well-circumscribed mesenchymal neoplasms at this locations. Introduction: We present a rare case of a Extrapleural SFT in a 57 years old man in the neck, without significant past medical history. Material and Methods: The patient had a painless slow growing tumor, in right sight of the neck, diagnosed with physical examination. Total excision with local anesthesia was done, without previously biopsy of the tumor and other clinical investigations. Standard procedures for histology and immunohistochemical stains were done. Results: Tumor was well circumscribed, encapsulated measuring 5,5x4x4 cm. On section, the cut surface had a multinodular, whitish and firm appearance. On microscopic examination tumor was composed of alternating hypocellular and hypercellular areas separated from each other by thick bands of collagen and branching haemangiopericitoma like vessels. The tumor cells were round to spindle-shaped with little cytoplasm, indistinct borders, dispersed chromatin within vesicular nuclei. Area of myxoid change and subcapsular focus of hemorrhage was present, and 2 mitoses/10 HPF were found. Immunohistochemistry revealed diffuse positivity for CD34, Vimentin and BCL2, focal positivity for CD99, S100, SMA, and negativity for CKWS and EMA. Ki67 showed low proliferating index 3-5%. Conclusion: Although most cases of SFT are benign, there is no strict correlation between morphology and behavior, so patients with extrapleural solitary fibrous tumor have need of long-term post-resection follow-up. Further studies are needed to determine the optimal management of these neoplasms.