The single supratentorial lesion

Abstract

The role of preoperative diagnostic tests was evaluated in 210 adult patients with single supratentorial lesions demonstrated by computerized tomography. At craniotomy, 59.5% of these patients had primary brain tumors, 36.2% had metastatic tumors and 4.3% had non-neoplastic lesions. In 23 (11%) of these patients, a single brain metastasis was the 1st manifestation of a systemic cancer. The primary site of cancer was identified in 14 patients (10 in the lung, 3 in the kidney and 1 in the colon) and in 9 patients the primary site could not be established. Using simple conditional probability theory, the probability of a metastatic lesion in patients without a history of previously treated cancer is .apprx. 7% if their chest X-ray film and i.v. pyelogram (IVP) are negative. Extensive preoperative testing to establish a primary site is unrewarding if the chest X-ray film and IVP are negative since these are the only sites likely to be identified in these patients. In patients with a history of previously treated cancer, these tests are justified because they have prognostic value in determining treatment.