Orbital cavernous haemangiomas: immunohistochemical study of proliferative capacity, vascular differentiation and hormonal receptor status.

Background/aims: Immunohistochemical characterisation of orbital cavernous haemangiomas (CHs) with respect to proliferative capacity, hormone receptor status and vascular differentiation.

Methods: Eleven cases of orbital CHs were reviewed. Immunohistochemical stains for Mib-1, proliferating cell nuclear antigen (PCNA), Bcl-2, estrogen and progesterone receptors (ER & PR), CD31, D2-40, and VEGF were investigated in 11 specimens.

Results: Immunohistochemical staining revealed positivity for PCNA in ten of the 11 cases (91%). Bcl-2 was positive in 8 cases (73%). VEGF and PR were each weakly positive in 3 cases. All cases were negative for Mib-1, ER and D2-40. The staining was localized around the endothelium.

Conclusion: This is the first study to characterise in detail the immunohistochemical features of orbital CHs. The proliferative markers PCNA and Mib-1 show discordant expression in these lesions and the expression of PCNA and Bcl-2 in the absence of Mib-1 is indicative of low proliferative potential. Small subsets of these tumors express PR and VEGF, which may partly explain the proliferative capacity of some orbital CHs.