Invasive inflammatory fibroid polyp of the stomach: A case report and literature review.

Rationale: Inflammatory fibrous polyp (IFP) is a distinct fibroblastic neoplasm with a predilection for the stomach and ileum. It usually presents prominent inflammatory infiltration, particularly eosinophils, and has been widely considered benign tumors without malignant biological behaviors. However, rare invasive cases have been reported.

Patient Concerns: A 75-year-old woman presented with unexplained hematemesis, dizziness, and weakness for 3 hours. Physical examination revealed upper abdominal tenderness on palpation.

Diagnoses: Contrast-enhanced computed tomography revealed a 6 cm nodule with a high-density shadow and ring enhancement with well-defined borders in the gastric body. Gastroscopy showed multiple gastric polyps as well as a gastric submucosal mass with surface ulceration and mucosal disruption. Emergency laboratory results revealed anemia symptoms with an erythrocyte count of 2.63 × 1012/L and a hemoglobin level of 58.00 g/L. A laparoscopic distal gastrectomy was performed. The pathological results support the diagnosis of invasive IFP, and the tumor cells were infiltrated into gastric's serosa layer.

Interventions: The patient underwent laparoscopic distal gastrectomy resection. In addition, the patient received blood transfusion therapy for severe anemia, including Leukocyte privative red blood cell and Fresh frozen plasma.

Outcomes: The patient was discharged home 2 weeks after surgery. There was no evidence of recurrence within the 4 years of surgery.

Lessons: Except the common gastrointestinal stromal tumor and leiomyoma, IFP should also be considered by pathologists in the diagnosis of primary gastric non-epithelial tumor. Our case also emphasizes the invasive nature of IFP, a rare non benign biological feature (only 5 cases have been reported previously). Although it is very rare, it represents the potential development of the tumor, and should be paid attention to by pathologists and physicians. Otherwise, we report this case because of the first case of an IFP presenting with both gastritis cystica polyposa and inverted hyperplastic poly.