Subcutaneous fluid collection in a 13-year-old soccer player.

Juvenile Xanthogranuloma.

Application of transesophageal echocardiography to detect a left atrial septal pouch thrombus as an unusual cause of cryptogenic stroke.

oral lesions of erythema multiforme.

Reasoning diagnostic features

(A) MRI: coronal T1-weighted sequences: Polylobulated multilocular thin-walled cystic formation with liquid-filled content measuring 100 × 72 × 60 mm, communicating through a small opening with the knee joint (black arrow). (B) MRI: Sagittal T1-weighted sequences: Polylobulated multilocular thin-walled cystic formation with liquid-filled content measuring 100 × 72 × 60 mm, communicating through a small opening with the knee joint (black arrow).

Plain radiography of bilateral hands revealing innumerable periarticular soft tissue calcifications without bony erosions.

Transverse section of contrast-enhanced Computed Tomography (CT) of the chest revealing mild enhancement at the region of the nodule and consolidation.