Bilateral and multiple mixed epithelial and stromal tumors of the kidney: A case report

Abstract

Mixed epithelial and stromal tumor (MEST) of the kidney is a benign tumor occurring predominantly in older women. Histologically, MEST comprises tubuloglandular and cystic structures in an ovarian-like stroma. Bilateral and multiple cases are rare. We herein present a case of bilateral and multiple MEST in a 43-year-old woman. The patient presented with gross hematuria and was referred to a primary care physician. A computed tomography scan revealed 5 tumors in the right and 2 in the left kidney. Renal cell carcinoma was suspected, and left partial nephrectomy followed by right radical nephrectomy was planned. After the left partial nephrectomy, the histopathological diagnosis was MEST, which was consistent with the results obtained following needle biopsy. Therefore, the contralateral tumor was also suspected to be MEST, and needle biopsy was performed. The histopathological diagnosis was identical and the right kidney was spared. The patient is currently periodically monitored. As MEST is a benign tumor, preoperative diagnosis is crucial for avoiding overtreatment.

Mixed epithelial and stromal tumor of the kidney: A case report

“…Due to this information it can be considered that hormones are a risk factor for this tumor. The clinical presentation of MEST is similar to typical renal tumor (1,2,(4)(5)6,8,(10)(11)(12). However approximately ¼ of known diagnosed MESTs were asymptomatic.…”

“…Current treatment strategy is based on surgical operation. Imaging studies usually reveal a cystic lesion with soft tissue components (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Microscopic findings consist of epithelium with mesenchymal tissue (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12).…”

“…Imaging studies usually reveal a cystic lesion with soft tissue components (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Microscopic findings consist of epithelium with mesenchymal tissue (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The risk of malignant transformation in a patient with MEST is highly dependent on the individual characteristics of a tumor, but in vast majority of patients, the neoplasm was of benign character and the prognosis is good (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12).…”

Case report: two rare cases of mixed epithelial and stromal tumor of the kidney and a review of the literature

“…Moreover, Minoda et al reported a patient who was diagnosed as having bilateral MESTK and underwent a left partial nephrectomy only and active surveillance of the right lesion ( 2 ). Our report shows that next generation sequencing cannot help guide further treatment.…”

“…Cases in males are rarely reported, especially in teenagers. The female to male ratio is about 6:1, with the mean age being 46 years ( 2 ). Patients mainly present asymptomatically, but it is also possible that they present with flank pain, palpable abdominal mass, and hematuria.…”