SOLITARY BENIGN TUMOR OF THE RIB

• Published in: Journal of The Showa Medical Association Vol. 64; no. 1; pp. 126 - 131
• Main Authors: OGASAWARA, Kazuto, MIYAOKA, Hideyo, TANAKA, Hirosi, INAGAKI, Katunori, FUJIMAKI, Etuo
• Format: Journal Article
• Language: Japanese
• Published: The Showa University Society 28.02.2004
• Subjects: bone tumor; fibrous dysplasia; rib
• ISSN: 0037-4342; 2185-0976
• DOI: 10.14930/jsma1939.64.126

Solitary tumors of the ribs are relatively rare. In this study, we report a patient with a solitary benign tumor of the 9th rib. A 30-year-old female consulted our hospital with right thoracic pain without etiological factors. At the 9th rib, pressure pain was noted and was exacerbated during movement. Plain radiography showed swelling of the right 9th rib and a clear-cut spindle-shaped transparent bone area. CT revealed a high-density phyma at the site. Contrast-enhanced MRI revealed a high signal intensity area with a relatively clear border on T2-weighted images. On T1-weighted images, a low signal intensity area was detected. Bone scintigraphy and gallium scintigraphy showed solitary abnormal accumulation in the right 9th rib, and tumorectomy was performed. Histopathological findings did not suggest malignancy, and fibrous dysplasia was diagnosed. There have been no abnormalities such as relapse for 7 months after surgery. Tumors that develop in the ribs comprise only 2.4% of all bone tumors. In these tumors, the incidence of fibrous dysplasia is 26%, making it highest among rib tumors. Metastatic bone tumors comprise the second highest percentage (18.6%), followed by osteochondroma (11.6%) . Fibrous dysplasia frequently develops in patients 10 to 19 years old, without gender difference. Monostotic fibrous dysplasia is observed in most patients. On plain radiography, frosted glass-like bone lesions are characteristic of fibrous dysplasia. The tibia shows the highest incidence, followed by the femur, rib, and humerus. In our department, we previously encountered a patient with eosinophilic granuloma and a patient with osteoid osteoma. These rib lesions are very rare. In this study, we compare the present patient with these two patients, with a review of the literature.