Duodenal Foveolar Adenoma: Case Presentation with Whole Exome Sequencing and Review of the Literature.

INTRODUCTION

Duodenal adenomas are most commonly associated with polyposis syndromes. Foveolar adenoma is an especially rare entity with an unknown aetiology. We present a case of duodenal foveolar adenoma with coexisting metaplasia, whole exome sequencing results, and the first literature review.

CASE PRESENTATION

Hereby, we present the case of a 58-year-old man, whose polypectomy specimen revealed a lesion composed of mainly foveolar cells with low-grade dysplasia and was concluded as foveolar adenoma. Due to the incomplete resection, polypectomy was repeated; this time, foveolar adenoma was diagnosed with high-grade dysplasia. Foveolar differentiation was proved with MUC5AC immunohistochemistry; in addition, KRAS and SMAD4 pathogenic mutations were identified.

DISCUSSION

Duodenal foveolar adenoma remains a controversial and an enigmatic entity. Our paper presents such a lesion with first low-grade, then high-grade dysplasia, and KRAS mutation, identical to gastric manifestations. The further sample of our patient suggests foveolar metaplasia as an aetiological factor that supports the literature data.