The liver and primary type IV hyperlipoproteinaemia: a pathological study.

We studied the histological structure of the livers of 36 patients presenting type IV primary hyperlipoproteinaemia. Electron microscopy revealed dilation of the smooth endoplasmic reticulum and rough endoplasmic reticulum as well as the presence of giant mitochondria containing para-crystalline inclusions. Steatosis was present in all type IV hyperlipoproteinaemic patients regardless of their weight or nutritional sensitivity (to alcohol or carbohydrate). The ultrastructural modifications observed by electron microscopy indicate an increased synthesis of very-low-density lipoproteins by the hepatocytes. An alteration in excretion cannot be ruled out with certainty even though the microfilamentary microtubular system was intact, since the qualitative and functional modifications in this system may be undetectable by electron microscopy.