Surgical Pathology Criteria

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
Both are HMB45 positive

 

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

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