Pyogranulomatous lymphadenitis with Splendore-Hoeppli phenomenon caused by Neisseria species in a domestic shorthair cat.

An 11-year-old male neutered domestic shorthair cat underwent investigations for right mandibular and prescapular lymph node enlargement and weight loss. Cytology of the mandibular and prescapular lymph nodes revealed marked pyogranulomatous inflammation and mild neutrophilic, non-septic inflammation, respectively. Excisional biopsy of both lymph nodes was performed. Histopathology of the mandibular lymph node revealed severe pyogranulomatous inflammation, with prominent Splendore-Hoeppli phenomenon. Histopathology of the prescapular lymph node was consistent with reactive lymphoid hyperplasia. A Neisseria species was cultured from tissue samples obtained from both lymph nodes, with sensitivity testing confirming susceptibility to amoxicillin-clavulanate. After a 4-week course of amoxicillin-clavulanate (20 mg kg-1 PO q12h), clinical signs resolved. The cat was clinically well with no evidence of recurrence of infection 2.5 years after presentation.