Mixed adenoneuroendocrine carcinoma of gastrointestinal tract: Report of two cases

Figure 1 Cecum mixed adenoneuroendocrine carcinoma consists of proliferation of two components. First component is represented by glandular structures with mucinous foci (A-B) and displays positivity for keratin 20 (C) without immunoreactivity for synaptophysin (D), with a high Ki67 index (E) and cytoplasmic expression of maspin (F); The second component is represented by solid tumor islands (G) that are negative for keratin 20 (H) and are immunoreactive for synaptophysin (I), with a lower Ki67 index (J) and slightly cytoplasmic expression of maspin (K).

Figure 2 Gastric mixed adenoneuroendocrine carcinoma consists of mixed proliferation of glandular with specific immunoexpression. Solid tumor areas (A); The glandular structures are reactive for keratin AE1/AE3 (B) and solid structures express synaptophysin (C); A high Ki67 index can be seen in both tumor components (D); The nuclear expression of maspin in the glandular component (E) reflects the tumor aggressiveness that is confirmed by predominance of this component in lymph node metastases (F).