Recurrent Caterpillar-like Arachnoid Cysts Following Initial Resection: A Unique Presentation of a Disorder Where the Limits of Modern Medicine Are Reached.

Of the many emergent neurological cases presenting to the emergency department (ED) and operating room (OR) for resection, arachnoid cysts are amongst one of the rarer pathologies. The proper resection of arachnoid cysts has substantially decreased the risk of recurrence. Current medicinal and surgical approaches have been refined over the years and prove to be successful for many patients.

Concomittant fibrous dysplasia with aneurysmal bone cyst formation within the skull, humerus and rib.

Polyostotic fibrous dysplasia (FD) is a rare pathology characterized by the abnormal and gradual replacement of normal bone (calcium hydroxylapatite of osteoid matrix) with fibrous connective tissue. Aneurysmal bone cyst (ABC) is a tumor-like benign lesion with blood-filled cavities that can affect virtually any bone in the body. We report on a 20-year-old male presenting with an extremely rare pathology of FD with ABC formation of the skull, fourth rib and humerus.