Successful treatment of a primary gastric plasmacytoma mimicking intractable gastric ulcer by using high-dose dexamethasone therapy: a case report

BACKGROUND: Extramedullary plasmacytoma is a plasma cell neoplasm that presents as a solitary lesion in soft tissue. Most extramedullary plasmacytomas involve the nasopharynx or upper respiratory tract. Primary plasmacytoma of the stomach is extremely rare. CASE PRESENTATION: A 78-year-old Korean woman presented with epigastric pain for 3 months. She had a history of an intractable gastric ulcer despite repeated endoscopic biopsies and appropriate medical therapy for the ulcer. She underwent another endoscopy and a biopsy was performed for multiple large and deep specimens. Ultimately, primary gastric plasmacytoma was confirmed. However, she and her attendant refused standard local radiotherapy or surgical resection. She came to our emergency room 3 months later with hematemesis due to a large gastric ulcer, despite management with medication for over 3 months at a local clinic. We again recommended local radiation or surgical resection. However, as she was willing to undergo only medical therapy, she was prescribed high-dose dexamethasone. Surprisingly, her ulcer completely regressed and remission was maintained for over 1 year. CONCLUSIONS: We report successful treatment of a rare primary gastric plasmacytoma mimicking intractable ulcer by using high-dose dexamethasone. To the best of our knowledge, this is the first reported case successfully treated with only high-dose dexamethasone.