PMC6906822_01
Gastroblastoma is a biphasic epithelial and mesenchymal tumor. Epithelial cells were characterized by round uniform nuclei, slightly eosinophilic cytoplasm, and inconspicuous nucleoli, are arranged also in glands or rosette-like structures containing luminal eosinophilic secretory material (a) and they showed strong pan-cytokeratin staining (d). Mesenchymal areas are organized in spindle cell fascicles (b) showing clear staining for vimentin (insert b). Necrosis is well represented (c). According to the biphasic nature of this neoplasm vimentin and CD10 are also expressed in epithelial glandular component (e-f). (Magnification 200x, scale bars 50 microm.)
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Histologically, the tumor showed a distinct biphasic pattern featuring epithelial areas haphazardly mixed with predominant spindle cell fascicles without any well-defined or abrupt transition (Figure 1). The epithelial component comprised epithelial cells displaying round uniform nuclei, a slightly eosinophilic cytoplasm, and inconspicuous nucleoli, mainly arranged in sheets, nests, cords and tubules (Figure 1(a)). Gland- or rosette-like structures showing dark and elongated nuclei were also present focally: luminal eosinophilic, secretory material was recognized as well (Figure 1(a)). On the other hand, the mesenchymal-type component was arranged in short fascicles or in a reticular pattern in loose stroma (Figure 1(b)). These cells possessed bland, oval to short spindle-shaped nuclei with inconspicuous nucleoli and scant cytoplasm (Figure 1(b)). Necrosis was well represented (Figure 1(c)). As far as immunohistochemistry, the epithelial component mainly expressed pan-cytokeratin (Figure 1(d)), low-molecular-weight cytokeratin (LMWK), epithelial membrane antigen (EMA), CK 7 and CK 19 (but only focally). On the other hand, the spindle cell component was reported positive for vimentin (Figure 1(b)), while expression of CD10 was observed with a focal pattern. According to the biphasic nature of this peculiar malignancy vimentin and CD10 were also observed expressed in epithelial glandular component (Figure 1(e)-1(f)).
Both epithelial and spindle cell components displayed a strong and extensive positivity for GLI1 by immunohistochemistry in a nucleus as well as in the cytoplasm. (Magnification 100x, scale bar 50 microm.)
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Both epithelial and spindle cell components displayed a strong and extensive positivity for GLI1 in a nucleus as well as in the cytoplasm (Figure 2).