Vol 27, No 5 (2022)
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Mixed epithelial and stromal tumor of the kidney: a case of a rare renal tumor presenting in a perimenopausal female

Onur Yildirim1, Mai Alkhatalin2, Kerime Hatun Ozgen1, Ahmad Yasin Alzu’bi3, Vedat Burkay Camurdan4
Rep Pract Oncol Radiother 2022;27(5):931-932.

Abstract

Not required fo Clinical Vignette.

clinical vignette

Reports of Practical Oncology and Radiotherapy

2022, Volume 27, Number 5, pages: 931–932

DOI: 10.5603/RPOR.a2022.0090

Submitted: 16.07.2022

Accepted: 11.08.2022

© 2022 Greater Poland Cancer Centre.

Published by Via Medica.

All rights reserved.

e-ISSN 2083–4640

ISSN 1507–1367

Mixed epithelial and stromal tumor of the kidney: a case of a rare renal tumor presenting in a perimenopausal female

Onur Yildirim1Mai Alkhatalin2Kerime Hatun Ozgen1Ahmad Yasin Alzu’bi3Vedat Burkay Camurdan4
1Department of Radiology, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
2Prince Hussein Hospital, Salt, Jordan
3Al-Hussein Salt New Hospital, Salt, Jordan
4Bursa Iznik State Hospital, Bursa, Turkey

Address for correspondence: Kerime Hatun Ozgen, Department of Radiology, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey; e-mail: ozgenkerime16@gmail.com

This article is available in open access under Creative Common Attribution-Non-Commercial-No Derivatives 4.0 International (CC BY-NC-ND 4.0) license, allowing to download articles and share them with others as long as they credit the authors and the publisher, but without permission to change them in any way or use them commercially

Key words: mixed epithelial and stromal tumor; kidney; renal tumor
Rep Pract Oncol Radiother 2022;27(5):931–932

A 45-year-old female with a history of urinary tract infection presented to our clinic with a left flank pain, fever, and dysuria. Her medical and family history was unremarkable, without a history of hormone therapy. Left pyelonephritis was suspected, and a CT abdomen/pelvis was performed for the diagnosis (Fig. 1).

Yildirim-3-1.png
Figure 1: Contrast-enhanced computed tomography (CT) scan (postcontrast sequences): a relatively well defined 4.0 x 3.5 cm predominantly cystic mass with associated mild heterogeneous, delayed enhancement within the septa and solid component on postcontrast sequences in the lower pole (A, B, and C). The mass extends into the renal pelvis and collecting system, causing a filling defect on the excretion series (D). The largest septum measures up to 0.9 cm

CT revealed a left multilocular relatively well defined predominantly cystic mass with associated mild heterogeneous, delayed enhancement within the septa and solid component on postcontrast sequences in the lower pole. The mass extends into the renal pelvis and collecting system.

MRI of the abdomen was performed for further evaluation and showed similar findings, including multilocular predominantly cystic mass with thick internal septa. Associated extension into the collecting system and delayed enhancement of septa and solid component was also noted (Fig. 2). Metastatic disease was ruled out. Cystic renal malignancy was suspected, and the patient underwent a left lower pole partial nephrectomy. The surgical margins of the specimen were clear.

Yildirim-3-2.png
Figure 2. Magnetic resonance imaging (MRI) of abdomen and pelvis: Transverse sections show multiloculated predominantly cystic mass with internal thick septa and solid components. Associated extension into the renal pelvis/collecting system (white arrows on A, B, and E) and delayed enhancement of septa and solid component (C and F)

Immunohistochemical stains revealed that the tumor stromal cells were positive for estrogen and progesterone receptors in the postsurgical specimen, supporting the diagnosis of mixed epithelial and stromal tumor. Microscopically, the tumor was composed of epithelial-lined cysts and stromal spindle cells, which mimic ovarian stroma by expressing estrogen and progesterone receptors. The postoperative course was unremarkable and at the follow-up, with a CT nine months after surgery, the patient was free of recurrence or metastases.

The mixed epithelial and stromal tumor of the kidney (MEST) is a rare and benign renal neoplasm originating from Mullerian-like stromal cells, accounting for 0.2% of all renal cancers [1, 2].

Approximately 100 cases of MEST have been reported in the literature, with the tumor occurring almost exclusively in perimenopausal women [3].

It appears that MEST incidence in perimenopausal women and women taking hormone replacement therapy are significantly correlated, suggesting a hormone-triggered mechanism [3].

Symptoms such as hematuria, flank pain, a palpable mass, or urinary tract infection are the most clinical presentation in the patients.

Generally, metastasis or recurrence of the MEST is not expected. However, MEST demonstrating malignant transformation and metastasis was reported in a few cases. Postoperative follow up of patients is necessary for ruling out the malignant transformation, although it is rare [3].

The tumor typically manifests as a multiloculated cystic renal mass, containing a variable proportion of solid and cystic components, containing internal septa, and showing heterogeneous, delayed enhancement on cross-sectional imaging. Herniation of the tumor into the renal collecting system may mimic urothelial carcinoma [3].

Preoperative diagnosis of MEST is challenging due to the lack of specific clinical aspects. Imaging studies cannot always differentiate MEST from other renal tumors, especially cystic renal carcinoma due to similarity in gross morphology. The definitive diagnosis is generally made by histopathology examination of intraoperative frozen specimens [3].

Top differential diagnosis includes cystic renal cell carcinoma, complex renal cyst, renal abscess, adult cystic nephroma, and multicystic dysplastic kidney.

We highlight the importance of considering MEST, which is rare, recently described, and overall a benign tumor with a good prognosis as a differential diagnosis of a renal multiloculated cystic mass in a perimenopausal woman.

Conflict of interest

The authors certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.

Funding

The authors report no involvement in the research by the sponsor that could have influenced the outcome of this work.

References

  1. Chu LC, Hruban RH, Horton KM, et al. Mixed epithelial and stromal tumor of the kidney: radiologic-pathologic correlation. Radiographics. 2010; 30(6): 1541–1551, doi: 10.1148/rg.306105503, indexed in Pubmed: 21071374.
  2. Montironi R, Mazzucchelli R, Lopez-Beltran A, et al. Cystic nephroma and mixed epithelial and stromal tumour of the kidney: opposite ends of the spectrum of the same entity? Eur Urol. 2008; 54(6): 1237–1246, doi: 10.1016/j.eururo.2007.10.040, indexed in Pubmed: 18006141.
  3. Lane BR, Campbell SC, Remer EM, et al. Adult cystic nephroma and mixed epithelial and stromal tumor of the kidney: clinical, radiographic, and pathologic characteristics. Urology. 2008; 71(6): 1142–1148, doi: 10.1016/j.urology.2007.11.106, indexed in Pubmed: 18313107.



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