Abstract

The light microscopy and clinical features of two patients with extrapancreatic tumours and hypoglycaemic episodes are described-together with the electron microscopy findings in one patient. The primary tumour of one patient arose within the skull and later metastasized to the liver, while the other patient had a locally recurrent intrathoracic tumour. Neither the intracranial origin nor the ultrastructural features support the concept of a mesothelial origin for these tumours, and they should be referred to as spindle-cell tumours associated with hypoglycaemia. There are ultrastructural similarities between these neoplasms and those of the pancreatic beta cells.