Reactive Fibroblastic and Myofibroblastic Proliferation of the Vulva (Cyclist's Nodule): A Hitherto Poorly Described Vulval Lesion Occurring in Cyclists

McCluggage, W. Glenn FRCPath^*; Smith, John H.F. FRCPath. American Journal of Surgical Pathology: January 2011 -  Volume 35 - Issue 1 - p 110–114.

Perineal nodules occurring in male cyclists are reported in the literature, although the histologic features are not  extensively documented. There has been little description of similar lesions in the female population. The overall morphologic appearances, especially in the cases with plump mesenchymal cells, bore some resemblance to proliferative fasciitis. Immunohistochemically, the cells were estrogen receptor positive and the plump mesenchymal cells were smooth muscle actin positive, in keeping with myofibroblasts. Desmin, S100, CD34, and HMGA2 were negative.

Pathologists should be aware of this pseudoneoplastic lesion occurring on the vulva, which arises in a specific clinical setting and has the potential to be misdiagnosed as a variety of other mesenchymal lesions.