RESUMEN
A polymorphic fibro-osseous lesion of the bone is a benign fibro-osseous lesion of the bone with a marked predilection for the proximal femur and characterized by a complex mixture of histological elements. We present one such case of a 35-year-old female with spontaneous onset of pain in the left hip for 3 months and trauma sustained a year ago. An examination revealed tenderness with painful movements over the anterior aspect of the left hip joint and trochanter. A clinico-radiological differential diagnosis of simple bone cyst or fibrous dysplasia was entertained. A microscopic examination of the lesion with clinico-radiologic correlation led to the diagnosis of a polymorphic fibro-osseous lesion. This is a genuine clinico-pathologic entity that is usually asymptomatic with a rare history of trauma or hip pain. It has a distinctive histopathological picture with a better prognosis than its mimics.