nesidioblastosis Abnormal proliferation of beta cells of developing islets often leading to marked diffuse or focal beta-cell hyperplasia. Considered to generate a potentially cancerous lesion. Beta-cell nesidioblastosis MPATH:499 congenital insulinomas diffused or generalised islet cell hyperplasia endocrine dysplasia focal adenomatosis microadenomatosis mouse_pathology.ontology multifocal and focal ductulo-insular proliferation (nesidioblastosis) nesidioblastoma nesidiodysplasia developmental dysplasia