Unconvincing diagnosis of a rare subtype of primary gastric lymphoma with incongruent endoscopic presentation: a case of gastric schwannoma.

Primary gastric lymphoma is a rare gastric malignancy. Its diagnostic process is complex. Clinician may find initial diagnosis of primary gastric lymphoma unreliable, especially when it indicates the rarest subtype of gastric lymphoma, while its initial endoscopic presentation fails to raise the slightest suspicion of primary gastric lymphoma. A 53-year-old Korean man was diagnosed, by endoscopic examination, with a round submucosal tumor of the stomach. Deep endoscopic biopsy, however, confirmed CD5 positive gastric lymphoma. Surgical treatment was performed for diagnosis and treatment. Postoperative histo-logical examination confirmed gastric schwannoma. Gastric schwannoma is a spindle cell tumor, characterized by a peripheral cuff-like lymphocytic infiltration. Deep endoscopic biopsy may have been misdirected to the peripheral lymphoid cuff, failing to acquire spindle cells. The literature has been reviewed, and options for diagnostic accuracy have been suggested.