Cystic low-grade collecting duct renal carcinoma with liver compression - A challenging diagnosis and therapy: A case report.

Background: A collecting duct carcinoma is a very rare, malignant renal epithelial tumor. Distant metastases are present in one third of cases at the time of diagnosis. It is known to have a poor prognosis.

Case Summary: A 42-year-old male was sent to our surgery clinic for removal of a 119.2 mm × 108.3 mm encapsulated cystic mass, which was localized in the 8 segment of the right liver lobe. The lesion was first identified on ultrasonography. A computed tomography scan confirmed the presence of a Bosniak type III cystic lesion, which affected the liver and convexity of the right kidney. Surgical intervention involved a right nephrectomy, with removal of the cystic mass. The patient was mobilized on the first postoperative day and was discharged after 7 d. The histological and immunohistochemical examination revealed a low-grade collecting duct renal carcinoma, which is a rare variant of papillary carcinoma, with low malignant potential. The patient did not receive chemotherapy and after 21 mo of follow-up, a radiological examination and laboratory analyses showed normal aspects. No relapse or other complications were reported.

Conclusion: To manage renal tumors properly, a correct histopathological diagnosis is crucial, as is early diagnosis and correct surgical treatment.