Fig. 1

Microscopic examination of hematoxylin and eosin-stained tissue sections (a) before and (b) after neoadjuvant chemotherapy. The tumor appears as an exophytic mass with stromal invasion and comprises small cells with scant cytoplasms, round-to-oval nuclei with a salt-and-pepper appearance, and abundant mitotic figures. Tumor cells stained positively for (c) synaptophysin and (d) chromogranin A