Gastric Plexiform Fibromyxoma
Differential Diagnosis
| GIST (spindled, bland) |
Gastric Plexiform Fibromyxoma |
| Usually solitary nodule |
Multinodular, plexiform |
| Myxoid pattern rare |
Myxoid pattern predominates |
| KIT and/or DOG1 74-95% |
KIT and DOG1 negative |
| CD34 frequently positive |
CD34 negative |
| Inflammatory Fibroid Polyp |
Gastric Plexiform Fibromyxoma |
| Usually solitary nodule |
Multinodular, plexiform |
| Usually a pedunculated polyp |
Intramural |
| Centered on submucosa |
Centered on muscularis propria |
| Frequent inflammatory infiltrate |
No intrinsic inflammatory infiltrate |
| May have concentric perivascular pattern of spindle cells |
Lacks concentric pattern |
| CD34 frequently positive |
CD34 negative |
| GI Leiomyoma, Myxoid |
Gastric Plexiform Fibromyxoma |
| Usually contains at least focal collections or fascicles of cells with distinct eosinophilic cytoplasm |
Indistinct or clear cytoplasm, no fascicles |
| Myxoid pattern rare |
Myxoid pattern predominates |
| Desmin usually positive |
Desmin negative |
| Fibromatosis, Mesenteric or Retroperitoneal and Pelvic |
Gastric Plexiform Fibromyxoma |
| Long fascicles of cells |
No fascicles |
| Myxoid pattern rare |
Myxoid pattern predominates |
| Areas of dense collagen frequent |
Lacks dense collagen |
| Usually extrinisc mass invading bowel wall |
Intrinsic to bowel wall |
| CD117 frequently negative, variable reports of focal/weak staining |
CD117 74-95% positive |
| DOG1 negative |
DOG1 87-94% |
