Histologically, it is characterized by a tubulopapillary and solid growth pattern resembling the primitive gut
; additionally, GCED is usually overlaid by a conventional adenocarcinoma (CA) component, which suggests that CA in the mucosa differentiates into GCED during the process of tumor invasion and proliferation .
At the 3rd-4th week of development, as a result of cephalo-caudal and lateral foldings of the embryo, a portion of the endoderm-lined yolk sac cavity is incorporated in the embryo to form the primitive gut
. Primitive gut
is composed of four main regions, namely, pharyngeal gut, foregut, midgut, and hindgut (Figure 1).
Of these, persistence of foetal gut diverticula, defect in recanalisation of the solid stage of primitive gut
, partial twining and the split notochord theories are popular.
The origin of placental teratoma is obscure but germ cell theory is widely accepted2 According to this theory in the early stages of embryogenesis the primitive gut
evaginates into the umbilical cord during which time primordial germ cells from the primitive gut
migrate through the gut wall and are deposited in the connective tissue of the cord and eventually pass into connective tissue between amnion and fetal surface of
Congenital gastric heterotopia may be associated with other entities such as a Meckel's diverticulum or duplications; it is believed that these lesions develop from the primitive gut
epithelium as a congenital anomaly, becoming hyperplastic over time.