Orbital diffuse large B cell lymphoma as a mimic of acute invasive fungal sinusitis.
The incidence of acute invasive fungal sinusitis is higher in immunocompromised individuals, such as poorly controlled diabetes mellitus and hematologic malignancy. The common pathogens are Aspergillus spp. and Mucorales. Rapid clinical deterioration despite appropriate medical treatment is a hallmark of this condition, and diagnosis can be difficult. On several occasions, empirical treatment has to be urgently initiated when tissue histopathology is not available to avoid poor clinical outcomes. We report a rare presentation of diffuse large B cell lymphoma involving the orbit, mimicking invasive fungal infection, in a 61-year-old female with rheumatoid arthritis and good controlled diabetes mellitus who presented with progressive right eye protrusion for two weeks. The initial orbital CT scan revealed an infiltrative, homogeneously enhancing lesion occupied in the right orbit's inferomedial extraconal space. Empirical antifungal therapy was begun, and surgical intervention was performed for diagnosis and treatment. However, gross findings were not classic for invasive fungal disease, and tissue histopathology was consistent with diffuse large B cell lymphoma. Antifungal therapy was halted, and chemotherapy was given with good clinical response.