HISTORY

A 7-year-old, intact male German Shepherd dog was visited for an acute onset of edema in ventral areas of the body. Previous medical history was unremarkable. Subcutaneous edema in scrotum, preputial area and distal limbs, and enlarged lymph nodes were found on physical exam. CBC was normal. Serum biochemical abnormalities were hypercholesterolemia and hypoalbuminemia. Urinalysis only showed proteinuria. FNA of peripheral lymph nodes was compatible with lymphoma. Additional tests were performed to stage lymphoma, confirm protein-losing nephropathy (PLN) and rule out other causes of PLN. Abdominal and thoracic radiographs and abdominal ultrasonography were normal. Serum leishmaniosis & ehrlichiosis titers were negative. Bone marrow cytology yielded normal results. Urine culture was negative and urine prot/creat ratio was 15. Further diagnostic tests were blood pressure determinations and serum antithrombin III which were also normal. Diagnosis of PLN and nephrotic syndrome associated with

DISCUSSION

Meningioangiomatosis (MA) is a rare vascular malformation of the central nervous system. It is a benign, focal proliferation of blood vessels and meningothelial cells in brain and leptomeninges. There are only a few reports of MA in dogs. Most of them described the lesion as a congenital vascular malformation, but in some cases neoplastic cells are present. In this dog there was a benign proliferation of spindle-shaped cells arranged in whorls around small blood vessels. Proliferating meningothelial cells infiltrated the brain and formed perivascular cuffs, those cells stained positively for vimentin and S-100. Necrotic areas were observed but any neoplastic cells or mitotic figures were detected.

The pathogenesis is uncertain but probably MA is a vascular malformation that is later accompanied by meningioendothelial cell proliferation without evidence of malignancy. Other hypothesis refers to a congenital hamartomatous malformation. In human medicine there are two populations of patients with MA: symptomatic children and young adults who present headaches or seizures, and asymptomatic individuals. In symptomatic patients, complete or partial resection can be curative.