case_images: PMC7714602_01
case_images: Serous borderline tumor/atypical proliferative serous tumor.
case_images: CRIOG2020-8896070.001.jpg
case_images: PMC7714602_01_CRIOG2020-8896070.001.jpg
case_images: fig1
case_images: The cystic component contained a serous borderline/atypical proliferative tumor (Figure 1) while the solid one appeared to be a high-grade LCNC, which was developed under the serous neoplasm on the cystic wall and comprised 40% of the tumor (stage pT1a/AJCC/2017).
case_images: High-grade large cell neuroendocrine carcinoma. High mitotic (yellow circle) and apoptotic (red circle) activity. Extended necrotic areas.
case_images: CRIOG2020-8896070.002.jpg
case_images: PMC7714602_01_CRIOG2020-8896070.002.jpg
case_images: fig2
case_images: Microscopically, the LCNC were characterized by the presence of islands, sheets, and trabeculae with little intervening stroma, cell necrosis, and high mitotic activity (Figure 2).
case_images: Positive neuroendocrine markers (chromogranin, synaptophysin, and CD56). High Ki-67 proliferation index.
case_images: CRIOG2020-8896070.003.jpg
case_images: PMC7714602_01_CRIOG2020-8896070.003.jpg
case_images: fig3
case_images: CD56 (cluster of differentiation 56) were partially while synaptophysin ubiquitously expressed in the neuroendocrine cells (Figure 3). CDX-2 (caudal-type homeobox transcription factor 2) and TTF-1 (thyroid transcription factor 1) were negative, as well as inhibin and calretinin.