Progesterone receptor expression in orbital cavernous hemangiomas.

Orbital cavernous hemangiomas (OCH) have thick and highly cellular vascular walls. Ultrastructural studies have demonstrated the smooth muscle nature of these cells. Vascular neoplasms can modify their morphological and clinical features under hormonal stimulation. The purpose of the present study was to investigate the presence of smooth muscle markers and sex steroid receptors in 12 cases of OCH. Orbital cases were compared with cutaneous hemangiomas and subcutaneous angioleiomyomas. Smooth muscle actin (SMA) and desmin were localized in spindle cells of the vascular walls of all 12 cases studied. OCH showed immunohistochemical positivity with progesterone receptor (PR) antibody both in smooth muscular and in endothelial cells. For comparison, sex steroid receptors were studied in 10 cases of cutaneous cavernous hemangioma and in 10 cases of subcutaneous angioleiomyoma. PR was found in smooth muscle and endothelial cells of 6 out of 10 cases of subcutaneous angioleiomyoma and in none of the cases of cutaneous cavernous hemangioma. No positivity was obtained with estrogen receptor (ER) antibody in any of the cases tested. The present data suggest that OCH share morphological and immunohistochemical features with subcutaneous angioleiomyomas. Furthermore, immunohistochemical positivity with PR antibody indicates that OCH have to be added to the list of mesenchymal lesions that express sex steroid receptors.