| Pleomorphic adenoma is a benign neoplasm that occurs in major or minor salivary glands. |
| Other primary epithelial tumors of the urachus include villous adenoma, transitional cell carcinoma, and, rarely, squamous cell carcinoma. |
| The villous adenoma from this patient demonstrated focal high-grade dysplasia but no apparent adenocarcinoma. |
| Conclusions: According to these findings, enucleation surgery on a pleomorphic adenoma should not be performed anymore. |
| The differential diagnosis on a biopsy included adenoid cystic carcinoma and basal cell adenoma. |
| Histology showed necrosed tissue, which was strongly indicative of pituitary adenoma. |
