Intraosseous hibernoma in the rib

Area of Science:

• Oncology
• Pathology
• Radiology

Background:

• Intraosseous hibernomas are rare benign tumors originating from mature brown adipose tissue within bone.
• These tumors can present with bone destruction and may be mistaken for malignant lesions on initial imaging.
• Diagnosis often requires a combination of imaging, macroscopic, and microscopic examination, including immunohistochemistry.

Purpose of the Study:

• To report a case of intraosseous hibernoma presenting as a destructive lesion of the rib.
• To highlight the clinicopathological features that aid in the diagnosis of this rare bone tumor.
• To emphasize the importance of considering benign entities in the differential diagnosis of osteolytic bone lesions.

Main Methods:

• A 64-year-old male patient presented with left-sided thoracic pain.
• Computed Tomography (CT) scan revealed an osteolytic lesion in the left seventh rib.
• Surgical en bloc excision of the tumor was performed, followed by macroscopic and histological examination, including immunohistochemical staining (S-100, CD68, CD34).

Main Results:

• Macroscopic examination showed a solid lesion measuring 3.5 cm × 3.0 cm × 3.0 cm with bone destruction.
• Histological analysis revealed tumor cells arranged in plates interspersed within bone trabeculae, with mature adipocytes present.
• Immunohistochemistry confirmed S-100 protein positivity and negativity for CD68 and CD34 in vacuolated cells.

Conclusions:

• The clinicopathological features were consistent with an intraosseous hibernoma.
• Intraosseous hibernoma should be considered in the differential diagnosis of osteolytic rib lesions.
• Complete surgical excision is an effective treatment for intraosseous hibernoma.