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

Case Report: A rare case of mixed epithelial and stromal tumor of the kidney in an adolescent: imaging findings and literature review

Mixed epithelial and stromal tumor of the kidney (MESTK) is an unusual biphasic benign renal neoplasm. It predominantly occurs in perimenopausal women, with only eight cases reported in children. Owing to its rarity, only limited radiological information has been reported in the literature, in none of the previous pediatric cases were both CT and MRI findings of the tumor provided. Herein, we report a rare case of MESTK in a 13-year-old girl. This case was the largest observed in children to date. Findings from our report provide novel insights into the MRI features of a large pediatric MESTK and indicate the importance of MRI for observing adipose components and the absence of diffusion restriction within the tumor. Radiologists should consider the possibility of MESTK in children when they observe a large, solid renal tumor without diffusion restriction in children.

Mixed Epithelial and Stromal Tumor of the Kidney: Clinicopathologic Features and Surgical Outcomes in Four Patients

Mixed epithelial and stromal tumor (MEST) is a rare neoplasm of the kidney that is seen mostly in middle-aged women with a history of hormonal contraceptive consumption. Mixed epithelial and stromal tumors are usually benign tumors with minimal chances of metastasis and recurrence. However, few malignant transformations of MEST have been recorded. In perimenopausal patients presenting with a complex cystic renal mass in the renal system with a history of selective estrogen receptor modulator (SERM) therapy, MEST must be a differential diagnosis. The key treatment in MEST is surgical resection of the tumor. A MEST is similar to adult cystic nephroma (ACN), but MEST has complex epithelial and stromal components.  We present a case series of four patients with a characteristic tumor of the kidney with the presence of mixed epithelial and stromal components. The ages of the patients ranged from 48 years to 55 years (mean age being 51 years). One of these cases is relatively rare as the patient is male and has no history of taking hormonal medications. Patients underwent surgical removal of tumors, and all of the patients recovered well postoperatively.

Multimodal imaging of mixed epithelial and stromal tumor of the kidney: Case series

BACKGROUND

To investigate the clinical features, imaging manifestations, and pathological characteristics of mixed epithelial stromal tumor of the kidney (MESTK) to improve the understanding of MESTK and the accuracy of preoperative imaging diagnosis.

METHODS

The clinical, imaging, and pathological data of 3 patients with MESTK confirmed by postoperative pathology were retrospectively analyzed.

RESULTS

Three patients with MESTK were middle-aged women with no obvious clinical symptoms. The main image representation showed a multilocular cystic or solid-cystic mass, with the larger masses protruding from the kidney contour, with multiple separations, which could be of unequal thickness. The cystic component showed no enhancement on enhancement scans, whereas the segregations and solid components showed gradual and obvious enhancement. Microscopic pathology was characterized by the biphasic differentiation of mesenchymal and epithelial components.

CONCLUSION

MESTK is a rare, mostly benign tumor that appears as a multilocular cystic or cystic solid, with progressive marked enhancement of the septal and solid components on enhanced scans. This imaging feature is helpful for the diagnosis of MESTK.

Myopericytoma/myofibroma as a stromal component of mixed epithelial and stromal tumor of the kidney: A case report

Mixed epithelial and stromal tumors (MESTs) of the kidney are rare renal neoplasms, primarily affecting middle-aged women. These tumors are characterized by a mix of epithelial and stromal components. While generally benign, MESTs require accurate diagnosis and appropriate management due to the potential for malignant transformation. The present study reports the case of a 75-year-old male patient who underwent a partial nephrectomy following the incidental discovery of a kidney tumor. Histopathological examination revealed a partially cystic tumor with solid areas, measuring 26 mm in diameter. The tumor had cysts lined with cuboidal cells and an ovarian-like stroma. The solid component consisted of elongated cells with eosinophilic cytoplasm and oval nuclei, showing angiocentric growth around small blood vessels without nuclear atypia or mitoses. Since the morphology of the solid component could not reveal the differentiation of those cells, immunohistochemical staining was performed and a myopericytoma/myofibroma component was established, mostly based on the positivity of smooth muscle actin, muscle-specific actin, h-caldesmon, estrogen receptor, progesterone receptor, solute carrier family 2 facilitated glucose transporter member 1 and collagen IV, along with a lack of staining for desmin, CD34, CD31 and CD99. Thus, to the best of our knowledge, for the first time in the literature, MEST with myopericytoma/myofibroma stromal component in a male patient was reported.

Unmasking the Mystery of Renal Neoplasm in a Perimenopausal Woman: A Case Report

Mixed epithelial and stromal tumor (MEST) is a benign, complex, and rarely encountered renal neoplasm. This case involves a 46-year-old perimenopausal woman who presented with symptoms, such as abdominal pain, burning sensation during urination, increased urinary frequency, and hesitancy. Computed tomography (CT) urography revealed an exophytic, heterogeneously hyperdense mass originating from the interpolar and lower pole parenchyma of the left kidney, suggesting a neoplastic origin. Due to concerns about malignancy and the presence of local symptoms, a laparoscopic-assisted left radical nephrectomy was performed. Histopathological examination of the excised tissue revealed a biphasic neoplasm consisting of epithelial and stromal elements. The epithelial component exhibited cysts and glands of variable sizes, lined by columnar cells and surrounded by stromal tissue. The diagnosis of MESTs of the kidney was established and confirmed through immunohistochemistry. This unique type of benign kidney tumor can be effectively managed through conservative surgery and is associated with a favorable prognosis.