A giant rheumatoid nodule of the cubital fossa: A mimicker of malignancy

Abstract

Rheumatoid nodules (RNs) are the most common extraarticular manifestation in patients with rheumatoid arthritis, appearing in up to 30%. They are typically localized subcutaneously in pressure points or joints, such as the extensor surface of the elbow. But when they have atypical localizations, they provide a confusing differential diagnosis including the possibility of a malignancy. Herein, we report a 53-year-old female patient with known rheumatoid arthritis who presented with a painless mass in the right cubital fossa. The uncommon site and the presence of cortical disruption made us proceed to computed tomography-guided biopsy to exclude the presence of a malignancy. Biopsy established the RN diagnosis.

Keywords: Cubital fossa; guided biopsy; rheumatoid arthritis; rheumatoid nodule; subcutaneous nodule.

Figure 1

(a-c): Axial T1-weighted MR images of the right elbow showing an isointense, well-defined mass (white arrow) within the supinator muscle and osseous involvement (open blue arrowhead). Encapsulated distal biceps brachii tendon (gray arrowhead)

Figure 2

(a-c): Axial STIR MR images of the right elbow showing a heterogeneous mass with high signal intensity (white arrow) in the anterior compartment, infiltrating the radius (open blue arrowhead)

Figure 3

(a-c): Axial, post-contrast T1-weighted fat-suppressed MR images of the right elbow showing vivid peripheral enhancement (gray arrowhead) and central necrosis (open arrowhead). Bone involvement is also noted (black arrow)