Incidental Splenic Granuloma Due to Burkholderia pseudomallei: A Case of Asymptomatic Latent Melioidosis?

We report a rare case of an asymptomatic latent melioidosis lesion in a posttraumatic splenectomy specimen from a diabetic patient. The 2-cm yellowish, lobulated lesion was found in the splenic parenchyma well away from the traumatized areas. Microscopically, it consisted of a central area of necrosis and exudate surrounded by macrophages, epithelioid cells, lymphocytes, and occasional multinucleated giant cells. <i>Burkholderia</i> bacilli were detected by a novel in situ hybridization (ISH) assay, and confirmed by polymerase chain reaction and sequencing to be <i>Burkholderia pseudomallei</i>. As melioidosis was not suspected initially, bacterial culture was not done but electron microscopy showed morphologically viable and dividing bacilli in the lesion. Moreover, the surgical wound became infected with <i>B. pseudomallei</i> several days post-surgery. After treatment with ceftazidime and trimethoprim/sulfamethoxazole, the wound infection cleared. We believe this could be a unique case of asymptomatic latent melioidosis in the spleen. In endemic countries, chronic granulomas should be investigated for <i>B. pseudomallei</i> infection, and if available, ISH may be helpful for diagnosis.