Secondary aneurysmal bone cyst in McCune-Albright syndrome.

Polyostotic fibrous dysplasia in combination with caféau-lait macules and hyperfunctioning endocrinopathies consists of a rare clinical condition termed as McCune-Albright syndrome. Aneurysmal bone cysts are tumor-like cystic lesions, composed of blood-filled compartments. They may occur as primary lesions or secondary to other pathologies; most commonly giant cell tumors of bone. However, secondary aneurysmal bone cysts in McCune-Albright syndrome are exceptional. We present a 28-year-old female with McCune-Albright syndrome. She experienced precocious puberty at age 3 months. In childhood, she experienced multiple long bone fractures, facial deformity and progressive visual and hearing impairment. One year ago, she experienced a painful, gradually enlarging bone lesion involving the right ilium, pubic and ischial bone with groundglass appearance, septa, marginal sclerosis, endosteal scalloping and blow-out expansion resulting in localized thinning of the cortex. CT-guided needle biopsy of the pelvic lesion showed aneurysmal bone cyst. Selective arterial embolization was recommended, however, the patient and her relatives did not consent to proceed to treatment, and she remained in close surveillance thereafter.