In mice, common metastatic sites are the lung, spleen, kidney, bone marrow and lymph nodes. Tumor cells are often found within pulmonary vessels and alveolar capillaries. Tissues fixed in Bouin's fluid more frequently exhibit immunoreactivity to the above antigens than tissues fixed in formalin. Mouse immunoglobulins are not found in histiocytic sarcoma cells, providing additional evidence of a nonlymphoid histogenesis. The specific cell of origin in murine histiocytic sarcomas is unknown.
Histiocytic sarcoma is the most common nonlymphoid hematopoietic neoplasm of rats and mice.
The tumors are transplantable and highly malignant. Uterine involvement is also strain dependent. Histiocytic sarcomas are rare in mice less than 12 months old, and are slightly more common in females. Mail Drop AO-01 Sciences, Research Triangle Park, NC 27709. The morphology, immunohistochemistry, and incidence of hematopoietic neoplasms in mice and rats.