A three-year-old male neutered Norwegian Forest cat was referred for bilateral ambulatory paraparesis and spinal pain. On magnetic resonance imaging (MRI), a mass involving the right epaxial muscles with vertebral canal invasion and causing marked extradural spinal cord compression was identified. At surgery, the mass was debulked and a right hemilaminectomy was performed. Histopathology was diagnostic of fibroblastic osteosarcoma. Residual osteolytic lesions of the osteosarcoma were present at the level of the spinous process of the second lumbar vertebra. Four cycles of adjuvant doxorubicin chemotherapy were administered followed by oral toceranib phosphate. Neurological signs improved gradually over weeks to months and the lesion in the spinous process was no longer visible on radiographs. At one year from diagnosis, an MRI of the T3-L3 (3rd thoracic vertebra to the 3rd lumbar vertebra) spinal region and a whole-body computer tomography (CT) scan found no evidence of the osteosarcoma in the spine or of any metastasis. All medications were stopped and, at the time of writing 16 months later, the patient is neurologically normal with no signs of cancer recurrence. This is the first case report documenting the complete resolution of vertebral osteosarcoma lesions after treatment with doxorubicin followed by toceranib phosphate. The treatment also prevented tumor recurrence and was associated with an exceptionally long-term survival time.

Lymphoma is the most common tumor of the nasal cavity in cats. Commonly used treatment modalities are radiotherapy and chemotherapy, or both. Typical chemotherapy protocols used in cats with nasal lymphoma are COP (cyclophosphamide, vincristine prednisolone) and CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone). Thus far, the use of single-agent chlorambucil in nasal lymphoma has been evaluated in a single case report. We report a case series of three cats with B cell nasal lymphoma, two cats with intermediate cell, and one large cell, all with a low mitotic index (MI) of less than 5 mitotic figures per ×400 field, treated with chlorambucil and prednisolone. Two of the cases achieved a long disease-free interval, while the one with the highest MI did not. Protocols using chlorambucil and prednisolone may have potential as a first-line therapy for feline nasal lymphoma cases with a very low mitotic index.

Histiocytic sarcoma (HS) is aggressive neoplasia arising from cells of the dendritic cell or macrophage lineage. Previously recognised negative prognostic factors are the presence of metastasis, anaemia, hypoalbuminemia, and thrombocytopenia. C-reactive protein (CRP) is an acute phase protein (APP), previously investigated as a prognostic marker in different neoplasms in human and veterinary medicine, including in Bernese Mountain dogs with histiocytic sarcoma, however no studies have evaluated serum CRP concentrations in all breeds with histiocytic sarcoma. Our study aimed to evaluate the prognostic value of serum CRP concentrations at the time of presentation and in different stages of the disease in a cohort of dogs, of different breeds, with histiocytic sarcoma. Dogs diagnosed with histiocytic sarcoma that not received any treatment prior to CRP measurement were included in the study. Patients were grouped according to the location of the primary tumour, tumour stage and treatment received (no treatment, localised treatment and systemic treatment)A Mann Whitney U was used to compare the CRP value with the stage and site of the tumour, while a Spearman’s correlation coefficient was used to compared the serum CRP with continuous variables. Thirty-five dogs were included. The median survival time for the entire population was 106 days. Increasing serum CRP concentrations (p = 0.009) and younger age (p = 0.003) were associated with decreased survival time in the multivariable model. No correlation was found between serum CRP concentrations and the stage of the disease (p = 0.327) or the site of the primary tumour (visceral vs. periarticular p = 0.504). Serum CRP concentrations and age may be additional prognostic factors in patients with histiocytic sarcoma, that are worthy of further investigation in larger studies.