Malignant histiocytosis is a rare hereditary disease found in the Bernese Mountain Dog and humans, characterized by histiocytic infiltration of the lungs and lymph nodes. The liver, spleen, and central nervous system can also be affected. Histiocytes are a component of the immune system that proliferate abnormally in this disease. In addition to its importance in veterinary medicine, the condition is also important in human pathology.[2]
A histiocyte is a differentiated tissue cell that has its origin in the bone marrow. The source for histiocytes is the monocyte/macrophage line. Monocytes (found in the blood) and macrophages (found in tissue) are responsible for phagocytosis (ingestion) of foreign material in the body. Langerhans cells are dendritic cells found in the skin and function by internalizing antigens (foreign particles) and presenting them to T cells. They arise from monocytes.[3] Histiocytic disorders refer to diseases that are caused by abnormal behavior of these cells. They include the following:
Reactive diseases of Langerhans cells (most important feature in immune histochemistry is expression of E-cadherin)
The disease in the lungs is characterized by enlargement of the tracheobronchial lymph nodes and infiltration of the lungs, sometimes leading to lung lobe consolidation and pleural effusion.[6] Signs and symptoms include cough, loss of appetite, weight loss, anemia, and difficulty breathing.[7]Seizures and rear limb weakness can be seen. Invasion of the bone marrow can cause pancytopenia.[8] Diagnosis requires a biopsy.
Other histiocytic diseases in Bernese Mountain Dogs[edit]
A similar disease is diffuse histiocytic sarcoma, a term used to designate a localized histiocytic sarcoma that has spread throughout the body. Other signs and symptoms include weight loss and loss of appetite.[9][better source needed]
^E Cadieu, B Hedan, G Parker H, Gr Rutteman, A Baffoe-Bonnie, et al.. Genetics of Malignant Histiocytosis in the Bernese Mountain Dog. 3rd International Conference on Advances in Feline and Canine Genomics, 2006, UC Davis, United States. pp.Inconnu. ⟨hal-02815226⟩
^Ettinger, Stephen J.; Feldman, Edward C. (1995). Textbook of Veterinary Internal Medicine (4th ed.). W.B. Saunders Company. ISBN0-7216-6795-3.
^Kearns, Shawn Ann; Ewing, Patty (Feb 2006). "Causes of canine and feline pancytopenia". Compendium on Continuing Education for the Practicing Veterinarian. 28 (2). Veterinary Learning Systems: 122–133.
^ abCronin, Kim (Dec 2006). "Deciphering the histiocytic code". DVM. Advanstar Communications: 1S–8S.
^Affolter V, Moore P (2002). "Localized and disseminated histiocytic sarcoma of dendritic cell origin in dogs". Vet Pathol. 39 (1): 74–83. doi:10.1354/vp.39-1-74. PMID12102221. S2CID17366063.
