Adenocarcinoma with a neuroendocrine component arising in the urachus. A case report.

The clinical, cytologic, histologic and ultrastructural findings in a mixed adenocarcinoma and neuroendocrine carcinoma of the urinary bladder urachus, an extremely rare tumor only recently described, are presented for a 31-year-old woman who died of widespread metastatic disease six months following the initial diagnosis and treatment. Cytologic study of voided urine and bladder washings disclosed the presence of malignant cells with the features of a small cell carcinoma; retrospectively, scarce adenocarcinoma cells were also identified in those specimens. Histologic study of resection specimens, including the use of special stains and electron microscopy, confirmed the presence of a small cell component, consistent with the poor prognosis in this case. Image analysis measurements of the malignant cells suggested a high proliferation rate.