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Updated: Jun 21, 2026

The Arteriovenous AV Loop in a Small Animal Model to Study Angiogenesis and Vascularized Tissue Engineering
Published on: November 2, 2016
Arteriovenous malformation with hair collar sign
Dylan Hollman1, Fatmah Alzahrani2,3, Loretta Fiorillo4
1Katz Group Centre for Pharmacy & Health Research, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
Abstract:
We report the case of a newborn who was noted at birth to have an occipital scalp nodule presenting with a hair collar sign (HCS). The nodule had enlarged since birth. An MRI revealed a soft tissue mass on the occipital scalp without deep extension or cranial bone involvement. A biopsy of the nodule led to a diagnosis of arteriovenous malformation (AVM). A vascular malformation with HCS has not been reported before in North America. This case highlights the complexity of diagnosing a lesion with a hair collar sign.
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