Chapter 7 – Case 1

A. Incorrect. The lesions as shown in figure 1-6 shows benign features (well defined margins, no periosteal reaction, no cortical destruction)

B. Incorrect. Paget’s disease is found in adults, not children.

C. Correct. The expansile lesion shown in figure 1-6 demonstrates ground glass appearance which is a characteristic of fibrous dysplasia.

D. Incorrect

E. Incorrect

A. incorrect answer. The maxilla is more commonly involved than the mandible in fibrous dysplasia.

B. correct answer. Fibrous dysplasia, an idiopathic benign fibro-osseous disorder, may be monostotic, polyostotic, or part of McCune-Albrigth syndrome (polyostotic fibrous dysplasia, café-au-lait-pigmentation, and sexual precocity in a female). Involvement of the facial bones and skull is more common in the polyostotic form.

C. incorrect answer. An expansion of the bone may narrow the spinal canal or neural foramina of the skull base. This may compress or entrap cranial nerves and result in cranial nerve palsy.

D. incorrect answer. Osteo-meatal obstruction by expansion of the bone may lead to a mucocele.

E. incorrect answer. There is a 0.5-1% incidence of malignant transformations, predominately osteosarcoma, fibrosarcoma and chondrosarcoma. The malignant tansformation is more often seen in the polyostotic form than in the monostotic form. Increasing pain, an enlarging soft tissue mass or a previously mineralized lesion that becomes lytic should raise suspicious for malignant transformation.

A. True.

B. True. Although the signal of pure fibrous tissue is hypointense on T2WI, that of fibrous dysplasia is variable.

C. True. A Fluid-fluid level has been described in fibrous dysplasias with cystic components.

D. False. Soft tissue extension of the lesion is unusual.

E. True. After gadolinium administration central, or less frequently, peripheral enhancement may occur.