Differential Diagnoses of Diseases Involving the Extrinsic Ocular Musculature ­ A Pictorial Essay

Introduction There are some inflammatory, infectious, and neoplastic diseases affecting the extrinsic orbital musculature (EOM) that present with pain, decreased visual acuity, and proptosis. Imaging is fundamental to the differential diagnoses of these diseases with similar clinical presentations. The present case series report has as main objective to illustrate and discuss the main pathologies that affect the orbit. Material and Methods The present series of cases discusses the main pathologies that can affect the extraocular musculature that can be characterized by computed tomography (CT) or magnetic resonance imaging (MRI) using cases from our institution. Results and Discussion The present study compiled several cases of ophthalmopathy from our institution to illustrate and address some of these pathologies, such as orbital lymphoma, Grave disease, metastases, periorbital cellulitis, and idiopathic orbital inflammatory syndrome. The diseases are discussed according to the presentation of clinical cases with emphasis on the main imaging findings of each pathology. Conclusion Computed tomography and MRI can help in the diagnosis and follow-up of the diseases that affect the EOM. We must be conversant with the main characteristics of the pathologies presented in the present case series report, since such findings together with clinical data can confirm the diagnosis of these diseases or at least help to narrow the differential diagnoses.

Paracoccidioidomycosis of the Central Nervous System: CT and MR Imaging Findings.

BACKGROUND AND PURPOSE: Paracoccidioidomycosis is a fungal infection mainly caused by the thermodimorphic fungus Paracoccidioides. The purpose of our study was to demonstrate the neuroimaging findings from 24 patients with CNS paracoccidioidomycosis. MATERIALS AND METHODS: We performed a retrospective analysis focusing on the radiologic characteristics of CNS paracoccidioidomycosis. The 24 selected patients underwent MR imaging and/or CT, and the diagnosis was made by the presence of typical neuroimaging features, combined with fungus isolation, a serologic test, or the presence of disseminated disease. RESULTS: Headache was the most common neurologic symptom, while the pseudotumoral form was the most common pattern. The number of lesions ranged from 1 to 11, with most localized on the frontal lobe with >2-cm lesions. CT showed mainly hypoattenuating lesions, whereas MR imaging demonstrated mainly hyposignal lesions on T1WI and T2WI. Furthermore, ring enhancement was present in most patients. The "dual rim sign" on SWI occurred in 100% of our patients with lesions of >2 cm. CONCLUSIONS: The diagnosis of CNS paracoccidioidomycosis is difficult. Nevertheless, imaging examinations can play an important role in the diagnosis and evaluation of the disease.