Combined laparoscopic-endoscopic "rendez-vous" procedure in a case of gastric schwannoma in a toddler

Introduction Schwannomas are rare benign tumors of the gastrointestinal tract. Despite the differences in features of schwannomas located in the stomach as opposed to peripheral or soft tissue schwannomas, their immunohistochemical characteristics are the same. We present a case of a 14-month-old boy with a gastric tumor who underwent a combined laparoscopic-endoscopic resection surgery, followed by gastric schwannoma diagnosis. Case outline The patient was admitted to our pediatric hospital with a fever of unknown origin. Endoscopy, performed after recurrent hematemesis, revealed an ulcer in the gastric antrum. At the four-week follow-up, gastroscopic and microscopic findings were normal. Two weeks later, a flank mass in the antrum was detected by an ultrasound examination. A new gastroscopy and CT scan confirmed the presence of a tumor-like mass, 5 cm in diameter. A combined laparoscopic-endoscopic polypectomy was performed with a necessary conversion for complete resection of tumor. The initial histological findings were consistent with a gastrointestinal stromal tumor. Due to this tumor's rarity in childhood, the paraffin-embedded tissue samples were referred for a second opinion. Histological and immunohistochemical characteristics of the tumor made the gastrointestinal stromal tumor diagnosis unlikely and consistent with a completely resected gastric schwannoma. No recurrence of the disease occurred during the seven-year follow-up. Conclusion Combined laparoscopic-endoscopic surgery is a feasible and effective treatment for large gastric tumors that cannot be excised endoscopically. Schwannoma should be included in the differential diagnostic consideration of gastric tumor lesions even in childhood.