Monostotic Fibrous Dysplasia of the Eighth Rib in a Young Woman: A Case Report

Abstract

Introduction: Fibrous dysplasia (FD) is a rare benign fibro-osseous disorder in which normal bone is replaced by fibrous tissue and irregular trabeculae of woven bone. Rib involvement is uncommon, and monostotic forms are particularly rare. This report aims to highlight the clinical presentation, diagnostic approach, and surgical outcome of monostotic fibrous dysplasia of the rib in a middle-aged woman.

Methods: A descriptive case report of a 37-year-old woman presenting with a long-standing, painless right chest wall swelling. Clinical evaluation, radiologic imaging, surgical management, and histopathological findings were documented and analyzed. 

Results: The patient presented with a seven-year history of a slowly enlarging, non-tender mass over the right lower chest wall. There was no history of trauma or systemic illness. Imaging showed an expansile lytic lesion with a characteristic ground-glass appearance involving the right eighth rib. Laboratory tests were normal. She underwent surgical excision via costectomy. Histopathology revealed irregular trabeculae of woven bone within a fibrous stroma, consistent with fibrous dysplasia. The postoperative course was uneventful, and she remained symptom-free at follow-up.

Conclusion: Monostotic fibrous dysplasia of the rib is a rare but important differential diagnosis of chest wall masses. Radiologic findings are suggestive, but histopathology confirms the diagnosis. Complete excision through costectomy is both diagnostic and curative, offering excellent outcomes. Increased awareness among clinicians can aid early recognition and appropriate management.