The purpose of this research was to evaluate the immunohistochemical expression of the vascular endothelial growth factor (VEGF-C1) and measuring the angiogenic activity by the staining for von Willebrand factor (vWF) and CD31 in oral pyogenic granulomas and hemangiomas. The results showed that there was no statistically significant difference in the angiogenesis index between the lesions evaluated. The average microvessel density determined for MVC (microvessel count) using CD31 was 60.64 for hemangiomas and 59.64 for pyogenic granulomas, while angiogenic index determined using vWF was 64.24 and 62.20 in these lesions. The results showed that the cells highlighted by staining for vWF were more uniform than in those stained for CD31. There was no statistically significant difference between the lesions for the number of cells highlighted by staining for VEGF-C1. However, the mean number of cells highlighted in pyogenic granuloma specimens was higher (153.23) when compared to oral hemangioma specimens (115.17). The VEGF-positive cells were endothelial cells and fibroblasts in hemangiomas and macrophages and fibroblasts in pyogenic granulomas. These results effort the role of the angiogenic factors in the etiopathogenesis of the hemangiomas and pyogenic granulomas, however, it showed that microvessel quantification is not useful in the differential diagnosis of these lesions.

Pyogenic granulomas after silicone punctal plugs: a clinical and histopathologic study. Am J Ophthalmol. 2005 Apr;139(4):678-84.

PURPOSE: To describe clinical findings, histopathologic changes, and risk factors for pyogenic granuloma formation complicating silicone punctal plug therapy. DESIGN: Retrospective observational case series. METHODS: Between November 2000 and April 2004, 903 silicone punctal plugs of the same brand were inserted in 404 subjects. Cases associated with pyogenic granuloma formation were identified and reviewed. Granulation tissue was obtained from 10 patients for histopathologic examination. Multiple risk regression analyses identified factors related to pyogenic granuloma development and factors associated with histologic patterns. RESULTS: Pyogenic granuloma development led to the extrusion of 4.2% of all plugs placed in a median time period of 141 days. All patients presented with varying degrees of plug extrusion. Similar distributions of partial and complete plug extrusions, as well as bilateral and unilateral plug extrusions, were seen. Findings at presentation ranged from a subclinical pyogenic granuloma causing partial plug extrusion to a pyogenic granuloma in the punctum with a ring of fibrovascular tissue retaining a completely extruded plug. Histopathologic examination revealed two patterns, representing either acute pyogenic granuloma or involuting pyogenic granuloma. Pyogenic granulomas resolved after 3.1 +/- 1.3 weeks in all patients after plug removal. Multiple regression analysis revealed that large plug size was associated with increased pyogenic granuloma formation (P < .0001). Partial or complete plug extrusion was associated with active or involuting pyogenic granuloma, respectively (P = .023). CONCLUSION: Pyogenic granuloma-related spontaneous plug extrusions may be more common than previously thought and can present with a range of clinical findings. The degree of plug extrusion correlates with the histopathologic pattern. Larger plug size and sharp edges in plug geometry may be responsible for pyogenic granuloma formation.