Intimal hyperplasia in the distal ulnar artery; Influence of gender and implications for the hypothenar hammer syndrome.

INTRODUCTION: The distal ulnar artery in the hand is subjected to trauma when the hypothenar eminence is used as a hammer. The clinical presentation of arterial obstruction or aneurysm formation at this site with a history of trauma to the hypothenar eminence is termed the hypothenar hammer syndrome (HHS) and is most commonly observed in the right hands of men. Since the trauma-inducing activities associated with the HHS are common, the histopathology of this arterial segment in our autopsy population was evaluated.
METHODS: The distal ulnar artery in the hand was examined in 21 randomly selected autopsies. Formalin-fixed paraffin-embedded cross sections of artery were assessed using hematoxylin and eosin (H&E), trichrome and elastic stains as well as immunohistochemistry for CD34 and alpha-smooth muscle actin.
RESULTS: Intimal hyperplasia is common at this site in the vasculature. The degree of intimal hyperplasia, as assessed by the intima/media ratio, is significantly greater in the right hands of men than in either their corresponding left hands or in women. None of the arterial segments examined contained foam cells or extracellular lipid deposits indicative of atherosclerosis.
CONCLUSIONS: In the injury-prone segment of the distal ulnar artery, intimal hyperplasia is common but is particularly severe in the right hands of men, correlating with the demographics of the HHS. Although, this arterial segment frequently develops intimal hyperplasia, it is resistant to the development of atherosclerosis.