Papillary mucinous cystadenoma of the kidney: Case report and review of literature

Epithelial tumors that originate from the kidney are uncommon. The majority of cases reported in the literature are malignant, with <1% of adenocarcinomas. Adenomas are even rarer. A case of mucinous cystadenoma of the kidney was diagnosed and treated in Cangzhou Hospital of Integrated TCM‑WM•HEBEI. The clinical feature of this disease was atypical. The principal symptom of mucinous cystadenoma of the kidney was a lump in the upper abdomen with intermittent pain in the abdomen. The tumor size ranged from 5‑12 cm. The patient was clinically diagnosed with multiple renal cysts with thickened walls and hemorrhage. The patient was admitted to the hospital five days later, and a left nephrectomy was performed. The tumor capsule was integrated and did not adhere to the adjacent tissue. One or multiple smooth‑walled dilated cystic areas were found on the cut section, some of which were filled with grey opaque gelatinous clots. Under light microscopy, the epithelial lining was characterized by a single layer of columnar with papillary proliferation and almost had no mitosis. Immunohistochemistry showed that the cyst was positive for carcinoembryonic antigen (CEA) and proliferating cell nuclear antigen (PCNA). Following nephrectomy, the patient was followed up for 8 years and no recurrence and metastasis were found. A total of five articles were retrieved, including six cases with mucinous cystadenoma of the kidney. The clinical feature of this disease was atypical, making clinical diagnosis difficult. Histopathological examination revealed that the cyst consisted of mucinous epithelium with supporting fibrous tissue and immunohistochemistry showed that the cyst was positive for CEA and PCNA. Patients with all resection of the affected kidney had an improved prognosis.