Urachal malignant fibrous histiocytoma: a case report and review of the literature.

Pathologic processes involving the urachus are usually related to inflammatory or sinofistular conditions. Neoplasms rarely arise within this structure, and when they do occur, they are typically epithelial, with mucinous adenocarcinoma being the most common. Mesenchymal lesions, both benign and malignant, have rarely been described in this location. We report the case of a 66-year-old white man who presented with a primary urachal malignant fibrous histiocytoma and died of metastatic disease 20 months after the initial diagnosis. This is an unusual case of malignant fibrous histiocytoma arising in a urachal remnant.