Cytomorphology of hibernoma: a report of 2 cases.

BACKGROUND: Hibernoma, a benign neoplasm of the brown fat, clinically and radiologically can mimic a lipoma or liposarcoma, especially in the retroperitoneum. As treatment modalities vary, an accurate preoperative diagnosis may help the surgeon to plan treatment. Hence cytologic features of 2 cases of hibernoma are described. CASES: Two middle-aged men diagnosed clinically as having lipomas were subjected to fine needle aspiration (FNA). Smears revealed typical hibernoma cells with a minor percentage of eosinophilic cells and mature adipocytes. CONCLUSION: FNA is a highly sensitive and specific tool for the diagnosis of hibernoma.