Inflammatory Disorders of Bone Marrow

Abstract

Inflammatory lesions in bone marrow, observed during a 2 year period at the College of Veterinary Medicine, University of Minnesota, were reviewed. Of 24 bone marrow specimens with evidence of inflammation, six were classified as acute inflammation, nine as fibrinous inflammation, five as chronic inflammation/hyperplasia, three as granulomatous inflammation and one as nodular lymphoid hyperplasia. Acute inflammation commonly accompanied bacterial sepsis. Two patterns of acute inflammation were identified. One pattern consisted of multifocal microabscesses. The other pattern of acute inflammation consisted of perivascular infiltrates of neutrophils, fibrin, edema, and hemorrhage. The most common disorder associated with fibrinous inflammation was disseminated intravascular coagulopathy. Chronic inflammation was difficult to differentiate from chronic immune stimulation. Discrete granulomas were identified in the marrow of animals with systemic mycotic disease, idiopathic systemic granulomatous disease, and serous atrophy of fat. This study indicates that a broad variety of inflammatory disorders occur in animal bone marrow and that these disorders can be classified based on general categories of inflammation described in other tissues.

Hemophagocytic syndrome in dogs: 24 cases (1996–2005)

“…Pathologic conditions that may be confused with hemophagocytic syndrome include malignant histiocytosis, necrosis, granulomatous inflammation, and monocytic and myelomonocytic leukemias. 10,[13][14][15][16][17][18] Malignant histiocytosis (also termed disseminated histiocytic sarcoma) is a malignant proliferation of myeloid dendritic cells. 14 However, cytologic features alone may be insufficient to differentiate malignant histiocytosis from hemophagocytic syndrome in some instances.…”

Cytologic Evaluation of Benign and Malignant Hemophagocytic Disorders in Canine Bone Marrow

“…Benign proliferative conditions of macrophages include bone marrow necrosis, 24 granulomatous inflammation, 25 and reactive hemophagocytic syndrome 7,8,26 . In bone marrow necrosis, phagocytic macrophages presumably are an appropriate response to the need to remove cellular debris 24 .…”

“…In bone marrow necrosis, phagocytic macrophages presumably are an appropriate response to the need to remove cellular debris 24 . Granulomatous inflammation has been documented in the bone marrow of dogs with disseminated fungal infection 25 . Reactive hemophagocytic syndromes have been documented in dogs with enteritis, lymphocytic leukemia, and myelomonocytic leukemia 7 .…”

Evaluation of blood and bone marrow in selected canine vector-borne diseases

“…It is also possible that infection-induced red cell abnormalities may alter membrane properties that result in reduced red cell lifespan and trigger phagocytosis [33]. Erythrophagocytosis may also occur as an "innocent bystander effect" whereby phagocytic macrophages remove red cells in the process of removing cellular debris, such as in the case of disseminated fungal infection [35], lymphocytic leukemia, myelomonocytic leukemia [36] and BM necrosis [37]. Erythrophagocytosis and platelet phagocytosis were observed in four A. platys infected dogs ( Figure 4A,B), consistent with the immunemediated thrombocytopenia that this pathogen is known to induce [38,39].…”