[Differential diagnosis to malignant neoplasia: Nasopharyngeal mass in a cat with nasal cryptococcosis in Germany].

Abstract

A 2-year-old Norwegian Forest cat was presented for evaluation of bilateral purulent nasal discharge and stertorous breathing. A computed tomography (CT) scan of the head revealed an intranasal mass of the left nasal cavity extending behind the tube openings and completely obstructing the nasopharynx. Rhinoscopy confirmed a pinkish, shiny mass. CT scan showed both compartments of the right middle ear filled with abnormal soft tissue attenuating material. There was no change in the bony outline of the middle ear. In the endoscopic examination, after endoscopically assisted tympanocentesis, this material in the accessible dorsolateral compartment proved to be classic polypous tissue in addition to highly viscous glue-like secretions. A secondary otitis media due to a drainage disorder was suspected.Using an endoscopic-interventional approach through the nostril, the nasopharyngeal mass was removed for histopathological examination, in order to restore the nasal airway, and to allow tube drainage. In contrast to cats with classical malignant nasal cavity masses, the cat showed several attachment points of the mass and multiple undulating elevations bilaterally in the nasopharyngeal mucosa.Cytological and histopathological examination identified the mass as a fungal granuloma in the context of a cryptococcus infection only rarely observed in Germany. Molecular genetic analysis confirmed an infection with Cryptococcus neoformans var. grubii.A single intranasal and nasopharyngeal endoscopic debridement resulted in a significant improvement of the clinical signs and a complete healing of the right middle ear (including the tympanic membrane) within 14 days, but not in a complete cure of the disease. The cat was therefore treated with oral itraconazole solution for several weeks.The case report shows that nasal cryptococcosis can also affect cats in Germany. Rhinoscopy reveals a nasopharyngeal mass with multiple attachment points, which is unusual for a neoplasia. In addition to the recommended removal of the mass, oral administration of systemic antimycotics is strongly advised.