Collagenous gastritis is a rare pediatric disease characterized by chronic gastritis with superficial, irregular mucosal involvement, focal atrophy of the gastric glands, an inflammatory infiltrate predominantly composed of lymphocytes and plasma cells, and areas of epithelial erosion. Focal collagen deposition in the subepithelial region of the lamina propria is a hallmark feature. Gastric epithelial erosions can cause hematemesis and, more generally, occult gastrointestinal bleeding, leading to chronic iron-deficiency anemia. Currently, there are no established management guidelines, and data on long-term follow-up are lacking. We report a clinical case of collagenous gastritis, emphasizing its features and therapeutic approach.

The freeze-dried rabies vaccine (Vero-cells) is generally safe. We present a rare case of a 44-year-old man who developed spontaneous intraperitoneal hemorrhage from a giant gastric gastrointestinal stromal tumor (GIST) shortly after receiving this vaccine. Emergency surgery was performed, and postoperative pathological and immunohistochemical analysis confirmed the diagnosis of a high-risk gastric GIST. The patient declined postoperative adjuvant therapy with imatinib. Follow-up evaluations at one year postoperatively indicated stable disease, and he has remained progression-free for 16 months to date, underscoring the indolent biology of gastric GISTs even in high-risk cases. This case serves as an important reminder for clinicians to consider underlying occult GISTs when evaluating acute abdominal symptoms after vaccination. Through this patient's journey, we emphasize the significance of performing comprehensive computed tomography (CT) examinations in patients with giant GISTs prior to rabies vaccination, and underscore the crucial need for heightened vigilance and close monitoring following administration of the freeze-dried rabies vaccine (Vero cells). Potential mechanisms that have been hypothesized to explain spontaneous tumor hemorrhage in this context include vaccine-induced inflammatory cytokine surges and hemodynamic changes. Although a rare case of rabies vaccine-associated thrombocytopenia has been reported, evidence for this mechanism remains limited. Further studies are warranted to clarify the relationship between vaccination and tumor rupture.

Gastrointestinal stromal tumors (GISTs) may occur anywhere along the gastrointestinal tract and lead to overt or occult luminal gastrointestinal bleeding. Small bowel GISTs can be particularly challenging to identify. Surgical resection is the mainstay of treatment for bleeding GISTs; however, the role of endoscopic hemostasis is less established. We present a case of a bleeding jejunal GIST diagnosed via capsule endoscopy and push enteroscopy after nearly a decade of negative endoscopic evaluations. Hemostasis was achieved with argon plasma coagulation and facilitated outpatient surgical resection. Clinicians should be mindful of this rare but important cause for small bowel bleeding.

Tumor rupture is a rare complication of uterine leiomyosarcoma. We report a case of ruptured uterine leiomyosarcoma diagnosed after the onset of abdominal pain following endoscopic examination of the lower gastrointestinal tract. The patient was a 56-year-old woman who was diagnosed with anemia at 48 years of age when she was first referred to our medical team. Contrast-enhanced magnetic resonance imaging (MRI) revealed a 48 × 50 mm mass in the anterior wall of the uterine body, which was diagnosed as a uterine fibroid. After 8 years of regular follow-up once or twice a year, the patient developed abdominal pain after undergoing lower gastrointestinal endoscopy, which was prompted by a positive fecal occult blood test result. Contrast-enhanced computed tomography (CT) showed that the uterine mass had enlarged to 90 × 69 mm. T2-weighted contrast-enhanced MRI demonstrated moderate signal intensity and restricted diffusion, whereas contrast-enhanced T1-weighted MRI revealed high signal intensity, suggestive of hemorrhage. The outlines of the tumor and uterus were interrupted cephalad to the lesion, raising the suspicion of rupture of a malignant uterine mesenchymal tumor. Therefore, total hysterectomy, bilateral salpingo-oophorectomy, and partial omentectomy were performed. Intraoperatively, tumor rupture and adhesion of the ruptured tissue to the ileum were observed, necessitating partial ileectomy. Pathological examination of the resected specimen revealed irregularly proliferating spindle cells with marked nuclear atypia, 12 mitotic figures per 10 high-power fields, coagulative necrosis, and multinucleated giant cell infiltration. Another notable finding was the presence of ectopic osteosarcoma and chondrosarcoma.

Small-bowel vascular malformations represent an uncommon but important source of obscure bleeding that can lead to iron deficiency anemia. Diagnosis and management can be challenging due to the intermittent nature and inaccessibility of small-bowel lesions. We present a 36-year-old man with recurrent iron deficiency anemia (IDA) requiring monthly iron infusions, in whom investigations using multiple modalities revealed the unusual finding of multiple small-bowel vascular malformations. Extensive investigations have failed to definitively localize a culprit bleeding point. This case highlights the diagnostic complexity of occult small-bowel bleeding and highlights the need for a coordinated multidisciplinary approach to establish an optimal management strategy.

Digestive angiodysplasia are acquired, superficial vascular lesions of the digestive tract, frequently implicated in overt or occult digestive gastrointestinal bleeding episodes. Their pathophysiology is not fully understood. They preferentially affect the elderly and comorbid patients. Their association with aortic stenosis is known as Heyde's syndrome. Diagnosis is based on digestive endoscopy (upper gastrointestinal endoscopy, colonoscopy and small bowel capsule endoscopy). Non-specific treatment includes management of blood thinners, iron supplementation (oral or intravenous) and blood transfusions. The specific first-line treatment is endoscopic destruction (argon plasma electrocoagulation being the most common), if necessary, by deep enteroscopy (with double balloon technique) in their jejunal and ileal locations. If endoscopic treatment fails, other treatments may be considered. In Heyde's syndrome, aortic valve replacement (surgical or transcatheter, TAVI) is often effective. Some pharmacological treatments have been shown to be effective, most notably long-acting release somatostatin analogues, followed by thalidomide (which has a poorer safety and tolerability profile). Bevacizumab, radiological embolization and surgery are only considered in most refractory or salvage cases.