Gelatinous Marrow Transformation and Hematopoietic Atrophy in a Miniature Horse Stallion

Abstract

Gelatinous marrow transformation, or serous atrophy of bone marrow fat, has been noted in livestock, laboratory animals, and wildlife in association with an inadequate plane of nutrition, inanition, or intoxication. This is a report of gelatinous marrow transformation and hematopoietic marrow atrophy in a 5-year-old miniature horse stallion. The horse had oral malformations leading to poor food assimilation and emaciation. A bone marrow biopsy obtained to investigate persistent anemia and leukopenia showed hematopoietic atrophy and replacement of fat with a granular extracellular substance, which stained with alcian blue, consistent with acidic mucopolysaccharide content. Surgical correction of the dental abnormalities resulted in improved food assimilation, weight gain, and resolution of cytopenias. In humans, gelatinous bone marrow transformation and hematopoietic atrophy are commonly associated with malnutrition from anorexia nervosa and other causes. The cause of hematopoietic atrophy is unknown but may relate to a nonsupportive marrow microenvironment and inadequate hematopoietic substrate availability. Similar pathogenic mechanisms were suspected in this horse.

MRI findings of serous atrophy of bone marrow and associated complications

“…This is supported by observing local MRI changes in bone marrow after treatment of extremity soft-tissue sarcoma, in which focal signal changes were observed in 37 % at a median of approximately 10 months after radiation therapy and/or chemotherapy [27]. If SABM is advanced enough to involve the pelvis or axial skeleton, then extensive, severe disease is usually present [28]. However, important aetiologies causing SABM include cachexia induced by cancer and chronic infection, and therefore great care must be taken to rule out neoplastic and infectious involvement of bone.…”

Persistent nonregenerative anemia in a 4‐year‐old cat

“…Despite occasional dysplastic changes in all lineages, the overall hypocellularity of the marrow and absence of increased blast cells are inconsistent with myelodysplastic syndrome 2 . The cat's 2‐month history of severe muscle wasting, weight loss, and decreased appetite is consistent with the diagnosis of GMT, which occurs with severe malnutrition 4 . GMT occurs secondary to inadequate nutrition in ruminants, minipigs, reindeer, rabbits, and miniature horses, and secondary to toxin ingestion and other disease states.…”

Nutritional Wasting Disorders in Sheep

“…Atrophic adipocytes over a faintly basophilic to amphophilic, extracellular matrix are detected in the depleted fat stores. This matrix stains light blue with Alcian blue, and is thus believed to be made of mucopolysaccharides rich in hyaluronic acid [19].…”