Case Report of a Hemangioblastoma With Large Blood Vessels and Rare Vascular Anomalies: Is It Fibromuscular Dysplasia or Arteriovenous Malformation Association?

Abstract

Hemangioblastoma is considered a benign neoplasm characterized by abnormal vasculature and stromal cells; several pathophysiological mechanisms have been proposed, such as genetic predisposition, hormonal factors, and arterial wall ischemia. Fibromuscular dysplasia is characterized by hyperplasia or thinning of the smooth muscle, elastic fibre destruction, fibrous tissue proliferation, and arterial wall disorganization. We present a cerebellar hemangioblastoma case not associated with Von Hippel Lindau syndrome. Histologically we evidenced big vessels with anomalies of the vascular walls corresponding to fibromuscular dysplasia, and those changes have not been described in these types of tumors. In this light, rare findings could be called vascular malformations or degenerative vascular changes, fibromuscular dysplasia or vascular anomalies. Arterio-venous malformation and hemangioblastoma pathology are rarely presented together. Notwithstanding, we could say that it is a stromal stem cell tumor in a varied stage of differentiation.

Keywords: arteriovascular; degenerative pathologies; fibromuscular dysplasia; malformation.

Figure 1. Axial view of the MRI of the brain

a: T1 weighted image (T1W), b: T2 weighted image (T2W) T1W, T2W and FLAIR images show a well-defined cystic lesion at the left cerebellum hemisphere of the brain. The T1W axial and T2W coronal images show a well-defined cystic lesion from the dorsally located mural nodule.

Figure 2. Histopathological analysis

A proliferation of blood vessels lined with an endothelium without atypia, intermingled with solid areas consisting of vacuolated stromal cells is seen. a: Small and fine vessels interspersed with stromal cells and fibrinoid necrosis are observed; b: Some stromal cells with the appearance of clear cells; c: Fibrovascular hyperplasia; d: Proliferation of endothelial cells; e: The big vessels show fibrovascular hyperplasia; f: Periodic acid–Schiff (PAS) stain shows this fibrovascular hyperplasia (x400); g: Myxoid changes, tissue appearance similar to chondroma; h: A proliferation of small vessels vascular lumen and stromal cells are observed in the large hyaline areas; i: Dense blue hyaline stroma in Masson's staining (x400); j: Reticulum staining shows distorted and fragmented wall vessels (x200); k: Vessels with dysplastic changes such as sclerosis areas, l: Irregularities of the wall with fragmented fibres are observed (reticulin stain x400)

Figure 3. Immunohistochemistry

a: The fine vessels are positive for CD34; b: The stromal cells are positive for hypoxia-inducible factor 1-alpha (HIF-1α); c): Vascular endothelial growth factor receptor 2 (VEGFR2) immunoexpressing x200; d: Glucose transporter 1 (GLUT1) stromal cells expression; d: Alfa-1-chymotrypsin nuclear immunoexpressing (x400); e: Vimentin is positive on the wall of the small vessels and in some endothelial cells (x200); f: Vimentin positive reaction in the wall vessels and cells, and vascular lumens is observed; g-h: Glial fibrillary acidic protein (GFAP) stroma positive immunoexpression around the neoplastic cells (original magnification x40).