GLYCOGEN IN NEUROBLASTOMAS - LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPIC STUDY OF 40 CASES

A light microscopic and EM review of 40 [human] cases diagnosed at Children''s Hospital of Pittsburgh [USA] as ganglioneuroblastoma, neuroblastoma or small round cell tumors (probably neuroblastoma) disclosed 4 cases that contained abundant glycogen. Two were unquestionable neuroblastomas by EM; 1 was primarily in the adrenal gland, the other in the mediastinum. In the 3rd case, a paraspinal tumor, the light microscopic appearance was suggestive of neuroblastoma, but no catecholamine granules of neural processes were demonstrated in the material available for EM. The 4th case was an undifferentiated malignant tumor in the pectoralis muscle of a 12 yr old girl. By EM, neural processes were demonstrated and the tumor was classified as peripheral neuroblastoma. Of the remaining 36 cases, EM readily indicated a diagnosis of neuroblastoma or gangioneuroblastoma in 35 of them. In the other case, the tissue had been fixed in formalin and only a few catecholamine granules were found after an extensive search.