Conclusions

• Malignant neoplasia of the left nasal cavity with focal destruction of the cribriform plate and perpendicular nasal septum, as well as secondary obstructive ipsilateral frontal sinusitis. Given the lack of external osseous destruction a chondrosarcoma or lymphoma can be considered more likely. A nasal carcinoma or other soft tissue sarcoma can be considered less likely. A mycotic rhinitis is not excluded.

Learning points

• Characteristics of malignant intranasal neoplasia include destruction of the nasal conchae and/or osteolysis of the nasal bones, invasion of the contralateral nasal cavity or frontal sinuses, heterogenous contrast enhancement and regional lymphadenomegaly.
• Infectious Rhinitis (e.g. mycotic > parasitic or bacterial), as well as an intranasal foreign body, should be ruled out as differential diagnoses. CAVE – organic foreign material is often not seen in CT.
• Adenocarcinoma, followed by undifferentiated carcinoma, transitional cell and squamous cell carcinoma, are the most common intranasal tumors in the dog. Chondrosarcomas, osteo- or fibrosarcomas are also common.

More information

• »Tomography, radiography, and rhinoscopy in diagnosis of benign and malignant lesions affecting the nasal cavity and paranasal sinuses in dogs: comparative study«
  – Top Companion Anim Med 2015; 30:39-42
• »Computed tomography as an aid in the diagnosis of chronic nasal disease in dogs.«
  – J Small Anim Pract 2005; 46:280-285
• »Diagnostic value of Computed tomography in dogs with chronic nasal disease«
  – Vet Radiol Ultrasound 2003; 44(4):409-413.
• »Differentiating Nasal Chondrosarcoma from Nasal Adenocarcinoma on Computet Tomography «
  — Am College Vet Rad 2012:102

Images courtesy of the Anicura Tierklinik Haar, Germany.