PMC9148250_01
A noncontrast CT scan of the patient's abdomen revealing thickening of the gallbladder wall with a possible polyp (white arrow).
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fig1
A noncontrast abdominal CT scan was performed where stones, a possible gallbladder polyp, and thickening of the gallbladder wall were identified, which were concerning for malignancy (Figure 1).
Representative H&E sections of the gallbladder LCNEC and some of the immunostains performed. Very low-power H&E view (20x) of the LCNEC showing necrosis and tumor cells (a), low-power H&E section (40x) showing the trabecular growth pattern (b), and a middle-power view (200x) showing the neuroendocrine features of the LCNEC (c). Sections (d-h) show the CD56, AE1/AE3, c-kit, neuron-specific enolase, and Ki-67 immunostains, respectively.
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fig2
Histologically, the tumor showed extensive necrosis and large cells with salt and pepper nuclei, prominent nucleoli, and a trabecular growth pattern (Figures 2(a)-2(c)). The tumor cells were immunoreactive to CD56 (membranous), AE1/AE3, c-kit, and NSE (cytoplasmic) (Figures 2(d)-2(g)) and negative for CD20, chromogranin, synaptophysin, DOG-1, S-100, and other markers performed, consistent with a LCNEC. The Ki-67 immunostaining revealed a brisk miotic index with over 95% immunopositivity (Figure 2(h)). The tumor was staged as pT3, pN1.