Monostotic fibrous dysplasia of the spine: report of a case involving the lumbar transverse process and reviewed the literature

Monostotic fibrous dysplasia of the spine is rare. We report its clinical, radiologic and histologic features affecting a 47-year-old housewife. She p resented with low-back pain of 1-year's duration, and radiographs showed a diffuse expansile lesion in the left transverse process of the fourth lumba r vertebra. The lesion was excised and histologically confirmed to be fibro us dysplasia, The patient remained well 8 years after operation. Including the present case, a total of 22 cases of monostotic fibrous dysplasia of th e spine were found in the literature. Combining these reported cases, we fo und that the condition affects either sex with equal frequency and presents at any age, the mean being 32 years. There is no predilection for any part of the spinal column, though sacral or coccygeal involvement is distinctly rare. It most commonly involves the body and adjacent pedicle, although no part of the vertebra is spared. It is worth noting that a propensity for p rogressive enlargement, even to the extent of causing graft destruction, ex ists if the lesion is left untreated or incompletely treated. Complete remo val of all involved bone, together with stabilization, should therefore be the treatment of choice for this condition.