Histological classification of nesidioblastosis: Efficacy of immunohistochemical study of neuron-specific enolase

Pancreatic specimens of six patients with nesidioblastosis were studied by light microscopy and immunohistochemistry in order to classify the changes of the endocrine pancreas and relate them to the clinical outcome. Neuron-specific enolase immunostaining was useful in demonstrating the distribution of whole pancreatic endocrine cells. The six cases with nesidioblastosis were classified into two types; four cases of focal type (head 1, body 1, tail 2), and two cases of diffuse type. The histological classification show a correlation to the clinical outcome. The patients with a focal body or tail type showed normal blood sugar levels immediately after operation. On the other hand the patients with both diffuse type and a focal head type needed medical treatment within a few months after operation. Therefore, these cases should be followed with great care postoperatively. A partial 80% to 90% pancreatectomy might be sufficient for each type except for the focal head type. When the intraoperative examination (both macroscopic and microscopic) is suggestive of focal head type, a pancreatectomy of 95% or more is called for.