Extracranial
metastasis of
primary central nervous system neoplasms is uncommon and has not been described in the dog. We report the clincopathologic features of
intracranial meningioma with pulmonary
metastasis in three dogs (case No. 1: 13-year-old castrated male Boxer dog; case No. 2: 14-year-old spayed female Dachshund; case No. 3: 6-year-old spayed female German Shepherd Dog). Case No. 1 presented with
ataxia,
lethargy,
vomiting, and leaning and falling to the right, and had a transient remission following radiation and
corticosteroid therapy; case No. 2 had a history of
seizures that were unresponsive to
primidone, left-sided postural reaction deficits,
ataxia, and circling to the right; case No. 3 had only intermittent episodes of
vomiting Computed tomography of case Nos. 1 and 2 revealed peripherally located homogeneous contrast-enhancing intracranial masses. Postmortem examination revealed intracranial masses with single or
multiple pulmonary nodules in all three cases. Histologically, the intracranial and pulmonary masses were
meningotheliomatous meningiomas with atypical features including brain infiltration,
necrosis, nuclear atypia, prominent nucleoli, and moderate cell density. All of the primary
meningiomas had low mitotic rates. The current interest in early diagnosis and aggressive clinical/surgical management of canine patients with
meningioma and other
primary central nervous system neoplasms will likely result in an increased detection of extracranial
metastases.