Surgical pathology criteria– search this site only stanford medical sites ways to give find a person alumni lane library ways to give find a person gastrointestinal stromal tumor (gist) differential diagnosis general differential diagnostic features of gist reactive antibodies (see supplemental studies): cd117 stains very few other spindled lesions but stains many carcinomas and melanomas cd34 stains many spindled lesions but stains almost no carcinomas or melanomas dog1 stains very few spindled lesions or melanomas or carcinomas spindled, bland gist ddx leiomyoma schwannoma fibromatosis sclerosing mesenteritis inflammatory fibroid polyp gastric plexiform fibromyxoma solitary fibrous tumor inflammatory myofibroblastic tumor endometrial stromal sarcoma calcifying fibrous pseudotumor spindled, malignant gist ddx leiomyosarcoma malignant fibrous histiocytoma dedifferentiated liposarcoma epithelioid gist poorly differentiated carcinoma melanoma/clear cell sarcoma glomus tumor gangliocytic paraganglioma gi endocrine carcinoma extramedullary myeloid tumor gi mucosal benign epithelioid nerve sheath tumo spindled, bland gist ddx gi leiomyoma gist (spindled, bland) usually arises in muscularis mucosae nearly always arises in muscularis propria cytoplasm usually distinct, eosinophilic cytoplasm frequently indistinct cd117 negative cd117 74-95% cd34 negative cd34 70% dog1 negative dog1 87-94% desmin 100% desmin 1-2% overall but 20% in esophagus dog1 is more sensitive for gist than cd117 in side by side comparison   gi schwannoma gist (spindled, bland) peripheral lymphoid cuff common lacks lymphoid cuff frequent cell size variation generally uniform cell size no skeinoid fibers may have skeinoid fibers s100 100% s100 5% (20% in small intestine) gfap 65-100% gfap negative cd117 negative cd117 74-95% palisading is more accentuated in gist; cd34 stains 0-33% of gi schwannomas   fibromatosis, mesenteric or retroperitoneal and pelvic gastrointestinal stromal tumor cd34 negative cd34 60-70% positive cd117 frequently negative, variable reports of focal/weak staining c. canada generic viagra buy generic viagra on line Viagra safe canada generic viagra uk next day delivery get viagra prescription yahoo donde comprar viagra yahoo Diferencia hay viagra viagra get viagra prescription yahoo buy viagra online from canada drugs generic viagra online without prescription is viagra generic any good viagra uk sales how to buy viagra over the counter viagra generic buy online Viagra jelly 20 mg m buy viagra online usa no prescription over the counter viagra walmart buy viagra from canada