Introduction: Primary, adult-type bone fibrosarcoma is an uncommon, malignant spindle-cell tumor of fibroblastic origin, rarely affecting children. Most frequently diagnosed among bone malignancies in the past, improved diagnostic techniques and further restrictive classification criteria have currently made the diagnosis of fibrosarcoma very unusual.
Case report: We hereby report the case of a 7-year-old child with a right frontal swelling mass. A computed tomography scan showed an osteolytic lesion of the right frontal bone, involving the diploe and the outer table of the skull. An en bloc surgical excision, followed by a thorough immunohistological evaluation, led to the diagnosis of fibroblastic proliferation, with low cellularity and minimal atypias. The patient had four recurrences during the 4-year follow-up. With an increasing histological grade at recurrences, a diagnosis of adult-type fibrosarcoma was made.
Conclusion: To the best of the authors' knowledge, this is the first reported case of an adult-type fibrosarcoma arising in the frontal bone of a child.
Keywords: Fibrosarcoma; Frontal bone; Immunohistochemistry; Molecular biology; Pediatric; Tumor progression.