Giant metanephric adenoma, benign tumor with features of clinical and radiological malignancy

IntroductionMetanephric adenoma (MA) is a rare benign neoplasm, accounting for 0.2% of adult renal epithelial neoplasms. This neoplasm mainly occurs in patients aged 50–60 years.AimThe aim of this study was presentation of rare kidney tumor assessment to elaborate proper postoperative decisions and further patient's recommendation.Material and methodsThe case of a 64-year-old woman with MA is presented. Radiological, intraoperative and pathomorphological evaluations of this neoplasm were performed and compared.Results and discussionPrimarily performed CT imaging analyzed this tumor as a malignant neoplasm; organ destruction and evident mass invasion in the calyx and kidney pelvis region were noticeable. Regardless of the initial radiological and clinical characteristic, postoperative pathomorphological analyses recognized the benign nature of this tumor; regularly located tubules and small cell regular outlook were observable. Attention was given to a solid fibrous capsule, which separated neoplasm from the rest of the healthy kidney structure. The patient was not qualified for adjuvant therapy, based on the pathomorphological evaluation due to characteristic nature of the benign kidney tumor. Nevertheless, in view of the initial observations (radiological and clinical) and because cases of metastases in the course of MA are described in the literature, a further periodic follow-up was strongly suggested to the patient.ConclusionsThe evaluation of neoplasm tumor requires many analyses. In this rare tumor lack of correlation was observed between radiological and pathomorphological examinations. The clinical decision connected with the patient's recommendation should be based on complete results, especially pathomorphological diagnosis. The patient is now under clinical observation and in six months follow-up has had no neoplasm recurrence or metastasis.