On clinical examination, upper respiratory tract stridor was evident and snoring and sneezing at rest. No nasal discharge was evident. Oral examination was unremarkable and no other abnormalities were evident on clinical examination apart from weight loss (0.5kg in preceding 4 weeks)

Routine haematology showed a mild regenerative anaemia (PCV 30.1 %) with a mild lymphocytosis (4.9 x 109/l). Serum biochemistry was unremarkable. Under anaesthesia chest radiographs showed no evidence of pulmonary disease. On rhinoscopy, retroflexion behind the soft palate revealed a soft tissue mass **picture**. Multiple biopsies were taken. Histopathology was inconclusive suggesting lymphoid hyperplasia. As lymphoma was suspected the dog was re-examined 10 days later to repeat biopsies. The owner reported quite a marked deterioration, with the dog now anorexic, lethargic and with occasional diarrhoea. Clinical examination revealed pallor and mild peripheral lymphadenopathy. The snorting and stridor continued. Repeat haematology showed a moderate poorly regenerative anaemia (PCV 25%) with mild lymphocytosis. Biochemistry was unremarkable. Abdominal imaging showed an enlarged right kidney with loss of normal architecture. One loop of small bowel was significantly thickened with loss of normal layering. One area 5cm x 3cm within the liver was hyperechoic. Numerous enlarged lymph nodes were evident and small amounts of free abdominal fluid was evident ** picture scans**Needle biopsies were taken from her lymph nodes, liver, right kidney, bowel and cytology performed on the free fluid.

Cytology from all sites showed atypical lymphocytes, with cytomorphology suggestive of a plasmacytoid T-cell lymphoma. After discussions with the owners they elected to proceed with multi-drug chemotherapy CHOP ( 26 week Madison-Wisconsin protocol). Within 36 hours her peripheral lymph nodes were normal size and her upper airway stridor resolved. Apart form occasional diarrhoea and one delay in her treatment due to neutropenia the dog tolerated the 26 week chemotherapy well. Her PCV had normalised by Week 6.

The dog enjoyed 6 months of remission before the clinical signs of stridor and diarrhoea recurred. Recurrence of the choanal mass was identified on rhinoscopy but again biopsies were interpreted as lymphoid hyperplasia. Relapse was eventually confirmed on cytology from rectal scrapes. Re-introduction of Madison-Wisconsin chemotherapy resulted in a second remission period and the dog is alive and clinically well in remission on chemotherapy 540 days after initial diagnosis.

Discussion

Four anatomical variations of lymphoma are reported in the dog; multicentric, alimentary, mediastinal and extranodal. Multicentric lymphoma is by far the most common seen (approximately 80% cases). Nasal lymphoma is considered rare and this case was unusual in presenting initially with nasopharyngeal disease. The pattern of renal and nasopharyngeal involvement is very unusual in the dog but has been reported in the cat (Morris ref). WHO staging (Stage Ivb), and T-cell phenotype are negative prognostic indicators ( Abbo and Lucroy 2007). Renal involvement is also thought to carry a poorer prognosis, although this may not be true in every case (Batchelor and others 2006) Immunophenotyping was not performed in the case, as it was not felt it would alter the treatment options. Although T-cell lymphomas are reported to have a poorer prognosis than B-cell lymphomas there is some suggestion that there are sub-classifications within the T and B-cell grouping that perhaps more accurately correlate with survival time (Ponce and others 2004) The cause of the anaemia in the case was not evident. Cancer patients can become anaemic through a number of potential mechanisms (Gould 2003). Immune-mediated haemolytic anaemia can be associated with haematological malignancies and this is one potential cause in this case. No spherocytes were seen on blood smears, in-saline auto-agglutination was negative. A Coombs test was not performed. Treating the underlying malignancy may resolve the anaemia, as was seen in this case. Anaemia at the time of diagnosis of lymphoma is usually associated with a decreased survival time (Miller and others 2009) , this case shows not all cases follow the prognostic indices we use. Resistance to chemotherapeutic drugs is often the cause for failure to introduce remission. The 26 week Madison-Wisconsin protocol has a high remission rate on re-introduction (80-90% cases go into remission) and unlike in COP-based protocols this period of remission can again be prolonged. Overall survival times with doxorubicin based protocols do suggest that some cases can achieve prolonged remission (Garrett and others 2002). Whilst there are a variety of tests that we can use to try and give prognosis in lymphoma, it is important to be aware that they all have their limitations and chemotherapy should not be recommended on the basis of these tests alone