Desmoplastic small round cell tumor (DSRCT) of the resected gastric tumor mass. (a) Gross examination: cut section of gastric mass revealed a 2.5 × 4.5 × 6.5 cm, irregular, ulcerated, necrotic, and hemorrhagic mass involving the gastric fundus and extending into cardia and lower gastroesophageal junction. (b) Histopathological examination: showing intact epithelial mucosa and presence of sheets of small round blue cells separated by minimal desmoplastic fibrous stroma. (c) Desmin immunostaining: showing positive cytoplasmic staining in the tumor cells (magnification power: ×400). (d) AE1/AE3 (cytokeratin) immunostaining: showing focal mild positive staining in the tumor cells (magnification power: ×400). (e) WT1 immunostaining: showing dot-like positivity in the tumor cells (magnification power: ×400).
