Leiomyosarcoma of the colon: report of a case and analysis of the relationship of histology to prognosis.

A case of primary leiomyosarcoma of the colon in a patient without gastrointestinal symptomatology who initially manifested a metastasis in the parotid region is described. Review of the literature indicates that mitotic activity is the most reliable histologic criterion for prognosis. Three of five patients with tumors manifesting high mitotic activity succumbed to widespread metastatic disease within four months of initial diagnosis. The prognosis is generally favorable for those patients whose neoplasms have low or moderate mitotic rates.