Botryomycosis ('bacterial ball') of the sinonasal tract caused by Pseudomonas aeruginosa

Background. - Botryomycosis is a chronic bacterial infection that typically presents as a cutaneous lesion. Visceral involvement may occur, but mucosal disease is uncommon. We report two cases of sinonasal tract botryomycosis that clinically simulated a neoplasm. Methods. - Two cases of sinonasal tract botryomycosis were identified from the Otolaryngic Tumor Registry at the Armed Forces Institute of Pathology, Washington, DC. The clinical records, slides, and paraffin blocks were available for both cases. Histochemical stains, including Brown and Hopps, Gomori's methenamine- silver, acid-fast bacilli, mucicarmine, periodic acid-Schiff, and Warthin- Starry, were performed. Results. - The patients were an 81-year-old man and a 43-year-old woman. The man presented with acute ethmoiditis and a bulging eye. Radiographic studies showed a soft tissue mass in his left maxillary antrum with osseous erosion of adjacent anatomic sites. The woman presented with persistent headaches of more than 1 year's duration, with increasing severity in the months prior to presentation. An expansile soft tissue mass was identified in her right maxillary and ethmoid sinuses. Surgery was performed on both patients. The histology included amorphous, acellular material and separate, rounded eosinophilic granules associated with a neutrophilic infiltrate. A Splendore-Hoeppli phenomenon was seen. Filamentous gram-negative bacilli, identifiable only by histochemical staining, were morphologically compatible with Pseudomonas aeruginosa. Cultures of samples taken from both patients intraoperatively confirmed the organisms as P aeruginosa. Conclusions. - Sinonasal botryomycosis is a rare localized disease that may be mistaken clinically for an aggressive neoplasm. Complete surgical evacuation is curative.