Diagnosis | Most common GI location | Characteristics | Positive immunohistochemistry markers | Mutations |
Gastrointestinal Stromal Tumor (GIST) | Any | Uniform pattern: spindle and epithelioid cells | CD117, DOG1, S100 (spindle 5.3%), Melan-A | c-KIT, PDGFR-α |
Melanoma | Small Intestine, Anus | Pleomorphism, mitosis, intranuclear inclusions | S100, HMB45, Melan-A, CD117 (63%) | BRAF |
Primary Clear Cell Sarcoma of the Gastrointestinal Tract | Small Intestine | Mostly epithelioid, prominent nucleoli, mitosis | S100 and negativity for HMB45 and Melan-A | t(12; 22) (q34; q12) EWS-CREB1 Fusion gene, t(12; 22) (q13; q12) EWS-ATF1 Fusion gene |
Leiomyoma/sarcoma | Esophagus | Spindle cells with blunt tips | Smooth muscle actin, Desmin | No |
Schwannoma | Rare | In the muscularis propria, lymphoid infiltrate | S100 | No |
Solitary Fibrous Tumor | Colon | Spindle cell, hemangiopericytic pattern | CD34, BCL-2 | No |
Fibromatosis | Mesenteric | Spindle, focal atypia | B-catenin | No |
Inflammatory Fibroid Polyp | Submucosal inflammation, no atypia or mitosis | CD34 | PDGFR-α |