Lymphangioleiomyomatosis
Differential Diagnosis
| Lymphangioleiomyomatosis | Metastatic Leiomyosarcoma |
|---|---|
| Cytologically bland | Cytologically atypical |
| Innumerable small clusters and nodules | Usually fewer, larger nodules |
| Virtually always forms cysts | Does not form cysts |
| HMB45 positive | HMB45 negative |
| Lymphangioleiomyomatosis | Metastatic Melanoma |
|---|---|
| Virtually always forms cysts | Does not form cysts |
| Virtually always forms cysts | Does not form cysts |
| Smooth muscle actin and desmin positive | Smooth muscle actin and desmin negative |
| Lymphangioleiomyomatosis | Emphysema |
|---|---|
| Discrete small cysts set in a background of normal lung | Irregular spaces blending with existing airways |
| Nodules of smooth muscle in walls of cysts | No smooth muscle nodules |
| HMB45 positive | Nothing in normal or emphysematous lung is HMB45 positive |
