Fibrohistiocytic Nodules

Last Modified: April 9, 2006


Dear OncoLink "Ask The Experts,"

My 9-year-old boy Freeway (dog, labrador) has been diagnosed with intermediate grade fibrohistiocytic nodule of the spleen. His spleen and a 7 cm mass that was removed, and he is recovering from the surgery extremely well. Canada West Veterinary Specialists in Vancouver BC are trying to find a chemotherapy regimen to help fight this rare cancer. Do you have any information or suggestions on treatment plans for splenic fibrohistiocytic nodule, (i.e. chemotherapy/holistic treatment plan, etc)?


Katherine Skorupski, VMD from the University of Pennsylvania School of Vererinary Medicine responds:

By definition, fibrohistiocytic nodules are not malignant cancers, but rather describe a spectrum of abnormal lymphoid cell growth (proliferation), either with or without fibrohistiocytic cells. Grade I nodules are equivalent to "benign nodular lymphoid hyperplasia", grade II nodules are called "benign fibrous histiocytoma", and grade III nodules are synonymous with "malignant fibrous histiocytoma". This last group of nodules have metastatic potential (i.e. the ability to spread to other sites away from the original location), and would more likely require additional therapy after surgery. It may be reasonable to seek a second opinion of your dog's biopsy in order to confirm the diagnosis (and to confirm that the lymphoid-to-fibrohistiocytic proportion is greater than 40%). If the diagnosis of grade II fibrohistiocytic nodule is confirmed, then further treatment is generally not necessary.