Immunocytochemistry (Ulex, factor VIII, JC/70A [CD31], PAL-E, BMA120, EN4, QBEnd10 [CD34], SMS actin) and ultrastructural studies showed no (marked) differences between different types of IMF.
Immunohistochemically, the nodules were found to be positive for vimentin and actin, but negative for desmin and S-100 protein; these findings support the myofibroblastic nature of IM.