The fine structure of papillary carcinoma of the thyroid

Eight human thyroid cancers (four papillary, and four lymph node metastases of papillary cancers) were studied at the ultrastructural level. The most characteristic anomalies affect the nucleus: "ground glass nuclei", highly indented nuclear membrane with formation of nuclear pseudoinclusions, nuclear bodies probably of nucleolar origin, fractionation of the periphery of the nucleus into multiple lobes joined by thin bridges of nuclear substance. Other abnormalities related to the mitochondria with decrease of size and number of cristae, the rough endoplasmic reticulum which was segregated in parallel saccules and the basal lamina was often reduplicated. The significance of these anomalies is discussed.