Fibrous Dysplasia Involving the Base of the Skull

Fibrous dysplasia: a case series of five cases

“…1,4,9 Skull and facial bones are affected in 10-25 % of monostotic form and 50% of polyostotic form. 3,6 Amongst the facial bones, maxilla is most commonly involved. 9 Other sites are temporal bone and sphenoid bone.…”

“…7,8 It describes the extent of skeletal involvement.  Homogenously dense pattern 6  Cystic variety. 6 Three radiographic standards in the cranial fibrous dysplasia and facial bones have been described 2,8  Pategoid -alternate radiodense and radiotransparent areas  Sclerotic -homogenously dense  Myxoid.…”

“…1,6 The variable intensity on T2WI resembles soft tissue tumor. 6 Localized fibrous dysplasia on MRI mimics a tumor because fibrous tissue enhances brilliantly after contrast administration.…”

“…5 It can affect a single bone, or even a small segment or the entire skeleton diffusely. 1,6 Fibrous dysplasia is a benign skeletal disorder typically seen in young adults. 1,7 it is not a true neoplasm.…”

‘Do not touch’ lesions of the skull base

“…Localised FD on MR imaging, however, may mimic a tumour because fibrous tissue has low to intermediate T1 and heterogeneous T2 signal and enhances after the administration of contrast material. 2,3 When MR is performed as the primary imaging modality in a patient with headache, for example, FD of the skull base is often diagnosed as an aggressive lesion, and the patient is referred to a tertiary care center for biopsy of what is often interpreted as a clival chordoma or metastatic focus. Recognising the benign expansion of bone with preservation of normal contours and the characteristically dark T2 signal of the fibrous tissue and suggesting a confirmatory CT of the skull base can help the patient to avoid an unnecessary biopsy (Fig.…”