Hibernoma
Differential Diagnosis
| Fat Necrosis | Hibernoma |
|---|---|
| Poorly circumscribed | Circumscribed |
| Foamy cytoplasm, few vacuoles | Multiple small vacuoles |
| Variable pattern from normal fat to necrotic fat to histiocytes | Uniform pattern |
| Lipoblastoma | Hibernoma |
|---|---|
| Restricted to children at presentation | Rare in children |
| Immature cells and lipoblasts | Microvesicular brown fat |
| 18q11-13 abnormalities | 11q13 abnormalities |
| Hibernoma with predominant mature fat | Atypical Lipomatous Tumor |
|---|---|
| Small, central bland nuclei in vacuolated cells | Lipoblasts, if present, have atypical nuclei |
| Lacks atypical nuclei | Contains atypical nuclei |
| Frequently superifcial | Rarely superficial |
| MDM2, CDK4, p16 negative | MDM2, CDK4, p16 most positive |
| Myxoid Liposarcoma | Hibernoma with Myxoid Stroma |
|---|---|
| Rarely superficial | Frequently superficial |
| Prominent "chicken wire" vascular pattern | Lacks "chicken wire" vascular pattern |
| t(12;16) or t(12;22) | 11q13 rearrangement |
