ORIGINAL ARTICLE

Microvascular proliferation in congenital vascular malformations of skin and soft tissue

Lorine B Meijer-Jorna¹, Chris M van der Loos¹, Onno J de Boer¹, Chantal M A M van der Horst² and Allard C van der Wal¹

¹ Department of Pathology, Academisch Medisch Centrum, University of Amsterdam, Amsterdam, The Netherlands
² Department of Plastic and Reconstructive Surgery, Academisch Medisch Centrum, University of Amsterdam, Amsterdam, The Netherlands

Correspondence to:
Correspondence to:
Dr A C van der Wal
Department of Pathology, M2-129, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands; a.c.vanderwal{at}amc.uva.nl

Background: Congenital vascular malformations (VMs) are mass-forming lesions that usually progress slowly, but may become symptomatic because of episodes of sudden growth and pain, particularly those with a substantial component of arteriovenous shunting.

Aim: To systematically investigate the features of microvascular proliferation in a large series of surgically treated VMs.

Methods: 107 resection specimens of clinically and histologically well-documented VMs were screened for the presence and extent of microvascular proliferation, based on morphological parameters, microvessel density (MVD), mast cell density (MCD) and proliferative activity (Ki-67 labelling index) of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). The extent of microvascular proliferation was correlated with the histological type of VM and clinical characteristics of patients.

Results: Microvascular proliferation was observed in 32 (30%) of all VMs, of which 30 cases seemed to be arteriovenous malformations. MVD in areas of microvascular proliferation was 282 (186)/mm² vs 13 (9)/mm² in areas with mature vessels. Both ECs and VSMCs in these areas showed high Ki-67 labelling indexes (mean (SD) 15 (18) and 17 (24)/mm², respectively). In all lesions, a positive correlation was found between MCD and MVD. Age, sex and location of VM had no predictive value for the occurrence of microvascular proliferation. However, if present, the involved tissue areas were larger and the proliferative activity of EC was higher in male patients than in female patients.

Conclusions: Recognition of microvascular proliferation as a not uncommon feature, congenital arteriovenous malformations provide new insight into the growth behaviour and vascular composition of these lesions.

Abbreviations: aAVT, acral arteriovenous tumour; AVM, arteriovenous malformation; EC, endothelial cell; GLUT, glucose transporter type; LM, lymphatic malformation; MCD, mast cell density; MVD, microvessel density; SMA-1, smooth muscle actin 1; VM, vascular malformation; VSMC, vascular smooth muscle cell; VVM, venous vascular malformation

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• Redondo, P. (2008). The Hidden Face of Venous Malformations: A Multidisciplinary Therapeutic Approach. Arch Dermatol 144: 922-926 [Full Text]