A histochemical study of bone marrow hypoplasia in anorexia nervosa.

The bone marrow in patients with anorexia nervosa is commonly hypoplastic with transformation of marrow fat. The normal fat cells which appear clear and open in the marrow are surrounded by an amorphous, gelatinous material, thought to represent an increase in the ordinary acid mucopolysaccharide ground substance of the bone marrow. Since this lesion has a similar appearance grossly and microscopically to the lesion of serous fat atrophy found in cachectic patients, we have compared the histochemical properties of this amorphous material in a bone marrow from a patient with anorexia nervosa and from cachectic patients with epicardial serous fat atrophy and with the background substance in hypoplastic marrows. Both this fat-associated deposition in the bone marrow and serous fat atrophy were found to be predominantly a hyaluronic acid mucopolysaccharide. In contrast, the background substance contained a less acid mucopolysaccharide. The increase in bone marrow acid mucopolysaccharide in anorexia nervosa may represent a serous fat atrophy change rather than an increase in ground substance.