Mycotic Olecranon Bursitis in a Diabetic Patient: A Rare Case Report.

Olecranon bursitis is a common clinical condition that is usually traumatic, inflammatory, or bacterial in origin. Fungal involvement of the olecranon bursa is exceedingly rare and may present a diagnostic challenge because of its indolent course and nonspecific clinical and radiological features. A 63-year-old female with diabetes mellitus presented with a gradually progressive, painless swelling over the posterior aspect of the left elbow of 1 year duration. Ultrasonography revealed a thick-walled cystic lesion with internal echoes and septations overlying the olecranon process, while plain radiography showed a posterior soft-tissue density lesion with tiny calcific specks. The lesion was surgically excised. Gross examination showed a cystic mass containing thick greenish purulent material. Histopathological examination revealed a fibrocollagenous cyst wall with dense mixed inflammatory infiltrates and fibrinous necroinflammatory material containing scattered fungal hyphae. Gomori methenamine silver stain highlighted fungal elements, confirming the diagnosis of mycotic olecranon bursitis. Fungal bursitis should be considered in the differential diagnosis of chronic, nonresolving olecranon bursitis, particularly in patients with underlying risk factors such as diabetes mellitus. Careful histopathological examination with special stains plays a critical role in establishing the definitive diagnosis and guiding appropriate management.