[Clinicopathological features of verrucous hemangioma]

Objective: To investigate the clinicopathological features, and differential diagnosis of verrucous hemangioma (VH). Methods: Twenty-eight VH cases diagnosed from 2005 to 2020 in Henan Provincial People's Hospital, Zhengzhou, China were analyzed retrospectively. Immunohistochemical studies were used to detect diagnostic markers. The mutation status of PIK3CA (exons 9 and 20) was detected using fluorescence PCR. Results: There were 13 males and 15 females in 28 cases, with the male to female ratio of 1.0∶1.2. There were 25 patients under the age of 18 years. The age range was from 10 months to 56 years (mean, 9.7 years; median, 4.5 years). There were 17 cases occurred in the lower extremities, 7 in the upper extremities and 4 in the trunk. All 28 cases were irregular red patches on the skin, which grew slowly. Some of them were thickened with uneven surface, which was light pink or red-white. Skin lesions of the 7 cases ranged from dark red and reddish brown, with a rough and hard surface. Satellite foci were present. Microscopically, 28 cases had a wide range of pathological features. Dilated, malformed vessels were observed from dermal papilla to deep soft tissue. Among them, the dermal papillary layer was mainly composed of many proliferating and expanding thin-walled capillaries and cavernous blood vessels. Thin-walled small vessels were found in the dermal reticular layer and subcutaneous fascia layer, with no obvious endothelial cell proliferation, occasional papillary hyperplasia, and lobular distribution of the malformed vessels in the fascia layer mixed with the fibroadipose tissue. There was epidermal papillary hyperplasia with hyperkeratosis and parakeratosis, lengthening and mutual fusion of epithelial horns. Immunohistochemistry showed that CD31, CD34, ERG and WT-1 were diffusely and strongly positive. The expression of GLUT-1 was present in superficial dermal vascular endothelial cells, but undetectable in the deep layer. The PIK3CA tests of 13 cases showed that no somatic mutations were found in exons 9 and 20. Twenty-five patients were followed up for 5 months to 10 years. Seven patients underwent multiple surgical resections and plastic surgeries due to the large size, and 8 patients had recurrence. Conclusions: VH is a rare congenital vascular malformation and more commonly occurs in infants and children. It tends to appear in limbs, especially lower limbs and distal limbs. Its morphology and immunophenotype are characteristic and should be distinguished from other vascular malformations and the resolution phase of infant hemangiomas. In about one third of the cases, postoperative recurrence may occur and long-term follow-up is often required.