Macroprolactinomas: CT evaluation of reduction of tumor size after medical treatment.

Thirty patients with macroprolactinomas were treated with dopaminergic drugs from a minimum of 4 months to a maximum of 6 years. Tumor size was evaluated with serial CT during treatment; serum prolactin levels and visual fields were also assessed at the same time. Reduction of PRL levels was found in 28 patients of whom 20 also had marked reduction of tumor volume on CT. Two patterns of reduction of size of tumor in relation with time were observed. In one, tumor shrinkage occurred rapidly in the first month and even in the first week after starting treatment. In the other pattern the tumor reduced in size only after some months of treatment. It is proposed that all patients with macroprolactinomas should be treated medically before considering surgery. A radiological diagnostic and research protocol is proposed, including scout views, thin slices, coronal sections, objective measurement of tumor size and density, serial CTs at 7,21,45 days, 6 months and then every year after the beginning of treatment.