Secondary aneurysmal bone cyst simulating malignant transformation in fibrous dysplasia

Fibrous dysplasia of the temporal bone: a review of 66 cases

OBJECTIVES/HYPOTHESIS

Fibrous dysplasia is a condition of nonmalignant osseous change and may occur in a monostotic or polyostotic pattern, the latter potentially being associated with McCune-Albright syndrome. Symptoms are highly variable and dependent upon lesion location and size.

STUDY DESIGN

Retrospective review.

METHODS

Consecutive subjects with fibrous dysplasia of the temporal bone were evaluated between 2000 and 2013 at two tertiary academic referral centers. Main outcome measures included disease presentation, diagnostic evaluation, management strategy, and outcome.

RESULTS

Sixty-six patients with fibrous dysplasia of the skull were found to have involvement of the temporal bone. The mean age at diagnosis was 25 years, 39 (59%) were female, and the mean duration of follow-up was 48 months. Six (11%) patients had monostotic disease, with the remaining 60 (89%) patients having the polyostotic form; 16 (24%) patients had McCune-Albright syndrome. The most common presenting complaint was headache (59%), followed by hearing loss (29%). The most common exam finding was cosmetic deformity (50%). Cholesteatoma (3%) and spontaneous cerebrospinal fluid fistula (1.5%) were found in a small percentage. No patients had evidence of motor cranial neuropathy by history or physical examination.

CONCLUSIONS

The clinical presentation of fibrous dysplasia involving the temporal bone is variable. A growing number of patients are diagnosed incidentally through imaging, and since most patients experience a benign course, the majority can be followed clinically without need for intervention.

LEVEL OF EVIDENCE

4.

Classic adamantinoma with osteofibrous dysplasia-like foci and secondary aneurysmal bone cyst

Adamantinoma, a rare bone lesion of the tibia and fibula, has two distinct variants, classic adamantinoma and osteofibrous dysplasia-like adamantinoma. Composite lesions have not been described. Aneurysmal bone cyst is a benign cystic lesion which may also occur in the tibia and fibula. We report an unusual case of classic adamantinoma with osteofibrous dysplasia-like areas and foci of secondary aneurysmal bone cyst with prominent giant cells. A lesion was diagnosed in a 17-year-old girl with a 14-year history of a slowly enlarging left tibial mass and increasing deformity. Pathologically, the predominant pattern was classic adamantinoma, with minor foci of osteofibrous dysplasia-like adamantinoma and areas of secondary aneurysmal bone cyst with abundant multinucleated giant cells. We report the clinical, radiologic, and pathologic features of this case, and summarize lesions associated with secondary aneurysmal bone cyst. To our knowledge, the association of adamantinoma with secondary aneurysmal bone cyst has not been previously reported.

Magnetic resonance imaging and [11C]methyl-L-methionine positron emission tomography of fibrous dysplasia--two case reports

Two cases of fibrous dysplasia in the skull base bone appeared hypointense on T1- and T2-weighted magnetic resonance imaging, with accumulation of [11C]methyl-L-methionine ([11C]Met) on positron emission tomography (PET). Fibrous dysplasia is a benign bone disorder which is identified by its distinctive radiography, computed tomography, and bone scintigraphy findings. [11C]Met PET may indicate the presence of viable tumor-like cells in fibrous dysplasia.