Abstract

A 68-year-old Japanese male was shown to have a spherical semipedunculated duodenal submucosal tumor (SMT) with a small central depression. He was followed up under the tentative diagnosis of Brunner gland (BG) hyperplasia (BGH) by biopsy. The tumor was found to have turned inverted dome-shaped with a central depression occupying almost all the top of it 2 years later. The disrupted surface was uneven, more reddened and lobulated by groove-like excavations, in and around which the mucosal pattern was obscured and abnormal vessels were observed. The biopsied specimen was interpreted as BG adenoma (BGA). The tumor was endoscopically resected because of a risk of complicating malignancy, judged to be completely excised, and definitely diagnosed as BGA containing no malignancy by the intensive examinations. Though explicitly proves that, contrary to the reports so far, dramatic macroscopic metamorphosis of BGA does not necessarily herald malignant degeneration within but is apparently due to disequilibrated blood supply, the present case implicitly omens, rather than completely excludes, the future possibility of canceration in the lesion on the grounds of the neoplastic findings.

Keywords: Brunner gland adenoma; Inequality in blood supply; Inverted growth; Macroscopic transformation; Malignant degeneration; Natural history