An unusual primary malignant tumor of the stomach: Fetal gut-like Gastric adenocarcinoma with “blastoma”-like component

Publication date: Available online 16 March 2017
Source:Human Pathology
Author(s): Altaf Taher, Nebojsa Denic, Sangeetha N Kalimuthu, Runjan Chetty
An unusual case of a polypoid, malignant gastric tumor in a 62-year man is presented. Endoscopy and subsequent polypectomy revealed an 8.5 x 6.5 x 4.5cm lesion in the body of the stomach. Microscopy showed surface dysplasia with an invasive adenocarcinoma displaying prominent tubulopapillary areas composed of large vacuolated cells, pleomorphic nuclei and occasional cytoplasmic hyaline globules. This component then blended with tubular structures lined by more primitive appearing vacuolated cells embedded within a stroma made up of cellular primitive, high-grade blastema-like areas and, less cellular more pleomorphic foci with spindle and several bizarre, large cells. Immunohistochemistry showed the adenocarcinoma and primitive tubules to be strongly SALL4 and epithelial marker positive, but only focal expression of α-fetoprotein and glypican-3. The stromal component made up of blastema-like areas displayed strong immunoreactivity for glypican-3. The pleomorphic stromal areas were negative for all markers, including epithelial and muscle markers. The overall morphology and expression of primitive oncofetal proteins, especially SALL4 and glypican-3, are in keeping with this being a primitive adenocarcinoma showing fetal gut-like differentiation with an accompanying blastoma-like component, a combination not previously described in a primary gastric cancer.



http://ift.tt/2mzp8wX