Immunohistochemical Demonstration of Cyclooxygenase-2 in Glomus Tumors

Background: Glomus tumors are benign hamartomas that account for 1% to 5% of all soft-tissue tumors of the hand. Painful spasms radiating from the lesion are typical clinical signs. As the pain production mechanism is unclear, we evaluated S100 protein, substance P, and cyclooxygenase-2 expression by immunohistochemistry in glomus tumor samples. Methods: Eight solitary glomus tumors were surgically excised and confirmed histologically by an experienced pathologist. Paraffin-embedded tissues were prepared for immunohistochemistry. The sections were stained with separate polyclonal antibodies for S100, substance P, and cyclooxygenase-2. In three of the tumors, we measured the prostaglandin E-2 concentrations. Results: All samples were positive for S100 protein and cyclooxygenase-2.Substance P was found in five of the eight samples. High prostaglandin-E-2 concentrations were seen in all three samples tested. Conclusions: Cyclooxygenase-2-immunoreactive cells are present in solitary glomus tumors. Since cyclooxygenase-2 produces prostaglandin E2, which is thought to be a strong vasodilator, the pain could be caused by vasodilation in the glomus tumor, with increased intracapsular pressure.