RESUMO
Background: Discrepancies have been noted between the clinical and histologic diagnosis of vascular malformations. Objective: To evaluate the effectiveness of the International Society for Study of Vascular Anomalies (ISSVA) classification in diagnosing benign vascular anomalies based on clinical and (immuno) histologic parameters, focusing on lymphatic differentiation and vascular proliferation. Method: A retrospective study of 121 consecutive patients with benign skin and soft-tissue vascular anomalies located in the head and neck region (pyogenic granulomas and angioma senilis were excluded) by applying multiplex immunohistochemistry staining for lymph vessels (D2-40), endothelial blood vessels, and proliferating cells (Ki67). Clinical and histologic diagnosis was revised after the ISSVA classification. Results: Initially, 64 lesions were diagnosed as tumors and 57 as malformations. Revision diagnosis following the ISSVA classification revealed 27 tumors, 90 malformations (22.2% lymphatic), and 4 non-ISSVA. Immunostaining showed lymphatic differentiation in 24 (19.8%) of 121 cases, of which 20 were malformations. Proliferative activity (Ki67+) was found in 41 (33.8%) of 121 cases, of which 8 were arteriovenous malformations. Limitation: Quality and size of materials (biopsies vs resections) and clinical information. Conclusion: The diagnostic accuracy of combined histologic and clinical approaches for identifying vascular anomalies following the ISSVA classification can be substantially enhanced by incorporating additional immunostaining techniques to evaluate lymphatic differentiation and proliferative activity, particularly in identifying the occurrence of vascular malformations.
RESUMO
BACKGROUND AND AIM: Arteriovenous malformations (AVM) are defined as being quiescent vascular masses composed of mature vessels. However, recent studies reported areas of microvascular proliferation (MVP) in AVM, indicating a process of angiogenesis. As this finding questions the previous definition, the primary objective of this review was to evaluate whether angiogenesis occurs in vascular malformations of skin and soft tissue, and second, to identify potential factors involved in MVP. METHOD: Due to the multifaceted nature of this subject, a hermeneutic methodology was used to select articles that were likely to provide a deeper understanding of MVP in vascular malformations. Through citation tracking and database searching in PubMed and Web of Science, relevant articles were identified. All study designs concerning occurrence of MVP in AVM of skin and soft tissue in all age groups were included in the study. The Newcastle-Ottawa scale was used for quality assessment. RESULTS: 16 studies were included in this review which reported occurrence of MVP areas in between the otherwise mature vessels of vascular malformations. In these studies, angiogenesis was reported only in AVM-type of vascular malformations. Increased levels of pro-angiogenic factors were also reported and proliferation was found most prominently during adolescence. Finally, several types of hormone receptors also have been described in tissues of AVM. CONCLUSION: Overall, the reviewed data support occurrence of active angiogenesis, highlighted by the presence of MVP in the arteriovenous type of vascular malformations, and a possible concurrent lesion progression towards a higher Schobinger stage of clinical severity. The relative scarcity of data at present implies that further research is required to elucidate the nature of MVP in AVM, which could have implications for developing targeted pharmacotherapy. RELEVANCE FOR PATIENTS: Active angiogenesis caused by MVP in AVM patients is known to be correlating to clinical symptoms and contributing to the progression of the disease, recurrence rate, and patient's quality of life.