Nasopharyngeal lymphomas vs. lymphoplasmacitic nasopharyngitis in cats : the endoscopist-pathologist alliance to meet the challenge

Nasalandnasopharyngeallymphomasarethemostcommonfelineupperrespiratorytrac tumors. However, nasopharyngeal lymphoma has been seldom considered a separate clinico-pathological entity. Nasopharyngeal lymphoma mimics severe inflammation and thus poses a challenge in its diagnosis. A high index of clinical suspicion along with multiple deep adequately sized and appropriately processed biopsies submitted for histology and immunohistochemistry are usually needed to achieve the correct diagnosis. Attempts to sample the tumors using endoscopic instruments are often unsuccessful because of the limited working space that can lead to the collection of non-diagnostic biopsies. In fact, an adequate amount of non-traumatized tissue sample is required for a definitive diagnosis since the frequent coexistence of the neoplasia with necrosis and inflammation. Commonly, nasopharyngeal lymphomas present as extensive multilobulated masses, that may, in severe cases, fill the caudal nasopharynx. In early cases, these lesions mimic clinically lymphofollicular inflammatory processes. Both lesions may be easily visualized by retrograde nasopharyngoscopy using flexible pediatric videobronchoscope. Combining retrograde nasopharyngoscopy with concurrent anterograde insertion of a large bioptic opposing-cups forceps trough the nares, allows to obtain larger and less damaged tissue samples for histopathology, under continuing endoscopic guidance. Patients often initially misdiagnosed as affected by chronic inflammation on clinical grounds had their diagnosis revised after histopathological examination of multiple samples excised with this technique. Microscopical examination often revealed the concomitance of lymphoma with chronic lymphoplasmacytic inflammation. This “anterograde-retrograde” technique proved ideal to sample primary nasopharyngeal lesions to confirm the diagnosis of inflammation versus lymphoma.