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Perineal nodular induration

Last author update: 1 September 2014
Last staff update: 28 October 2020

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PubMed Search: Perineal nodular induration

Nat Pernick, M.D.
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Cite this page: Pernick N. Perineal nodular induration. website. Accessed September 26th, 2023.
Definition / general
  • Rare reactive lesions reported in male and female cyclists and equestrians, due to repetitive perineal trauma (Hautarzt 2000;51:763, Int J Gynecol Pathol 2010;29:398)
  • They have also been termed cyclist's nodule, reactive fibroblastic and myofibroblastic proliferation of the vulva and "third testicle of the cyclist" (Histopathology 2003;42:615)
  • These lesions are benign but may recur; in this case (Case #326), after cessation of cycling and rest, the nodule went away
Case reports
  • 34 year old female cyclist with perineal cysts (Case #326)
  • In women, a recent report describes 4 cases of unilateral nodules or swellings of the labium major in competitive cyclists ages 15 - 45 years (Am J Surg Pathol 2011;35:110)
Microscopic (histologic) description
Case #326:
  • Mixture of adipose tissue, hyalinized tissue with bland spindled fibroblasts, blood vessels and nerve fibers, with variable perivascular lymphocytic infiltrate, thick cords of fibrous tissue, elastic fibers and epithelioid, plasmacytoid or ganglion-like cells
  • Spindle cells cells were immunoreactive for estrogen receptor and plump mesenchymal cells were positive for smooth muscle actin, consistent with myofibroblasts
  • These cells were negative for desmin, S100, CD34 (but see Int J Surg Pathol 2014;22:71) and HMGA2
Microscopic (histologic) images

Case #326

H&E images

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