ESR1 and neoplasm: On an immunohistological level, the tumor showed strong expression of synaptophysin (Figure 1a), SSTR2A (Figure 1b) chromogranin, nuclear hormone receptors (100% estrogen receptors (Figure 1c), 40% progesterone receptors), and GATA 3 (Figure 1d) supporting the hypothesis of a primary tumor of the breast rather than a metastasis of another (not detected) tumor.