Giant Intraosseous Lipoma of the Rib

Clinical Summary

A 74-year-old woman presented with a complaint of intermittent dull aching pain radiating to the left upper quadrant for the previous 2 months. There was tenderness with palpation in that region. Her chest X‐ray revealed a fracture of the 10th rib with accompanying blunt left costophrenic angle. Ultrasound examination revealed that a mass extending retroperitoneally from the left thoracic wall to the subdiaphragmatic area. Computed tomography (CT) scan revealed a well-defined localized expansile mass with a soft tissue center and internal thick septations. The lesion had a dimension of 7 × 4 × 3 cm. It originated from the thoracic wall and fractured the left 10th and 11th ribs and protruded into the subdiaphragmatic and abdominal area ([Fig. 1]). With these findings, the possible diagnoses were plasmacytoma, giant cell tumor, and aneurysmal bone cyst. The patient was operated under general anesthesia. During the operation the mass was seen to cover the 10th and 11th ribs and to extend to the subdiaphragmatic and retroperitoneal area. The thoracic wall was resected en bloc together with the left 9th, 10th, and 11th ribs. The mass had a thin capsule and contained numerous small bone particles ([Fig. 2]). Recovery was satisfactory, and the patient was discharged on the fifth day following the operation. Histological analysis provided a definitive diagnosis of parosteal lipoma with a calcified capsule ([Fig. 3]).

Fig. 1 Axial contrast-enhanced CT showing a well-defined, destructive lesion having a soft tissue center of cortical bone arising from the anterolateral end of the left 10th rib.

Fig. 2 Osteolipoma of the rib showing a thin capsule and a distinct multilobular pattern.

Fig. 3 Well-defined intraosseous lipoma composed of adipocytes with bone trabeculae (hematoxylin and eosin × 200).

References

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