Supplementary Material for: A challenging case of reactive angioendotheliomatosis

Introduction
Reactive angioendotheliomatosis (RAE) is a rare, benign, angioproliferative disorder with poorly understood aetiopathogenesis. It is characterised by vascular occlusion that occurs in patients with coexistent systemic or autoimmune disease.

Case presentation
A 60-year-old female presented with an 8-week history of a painful, non-healing, and non-traumatic ulcer on the left thigh. Her past medical history included smoking, peripheral vascular disease (PVD) and previously treated rectal squamous cell carcinoma. The diagnosis of pyoderma gangrenosum with superimposed cellulitis was considered and treatment with oral antibiotics was initiated. Following failure to improve a biopsy was undertaken which helped to confirm a diagnosis of RAE. The patient was referred for urgent consideration of surgical correction of PVD, but was deemed unsuitable for surgical treatment due to a poor performance status. The patient was treated with conservative measures, but her condition rapidly deteriorated and she passed away a few weeks later.

Conclusion
RAE is notorious for mimicking a wide spectrum of diseases. It is an important differential diagnosis to consider in patients with non-healing ulceration and underlying systemic or autoimmune disorders. Our case raises awareness of this rare condition and the mortality that it carries if left untreated. In an attempt to reverse disease progression and mortality, we urge clinicians to attempt surgical correction of PVD even when faced with multiple comorbidities and poor performance status.