mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
TRANSCRIPT
7/29/2019 mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
http://slidepdf.com/reader/full/mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm 1/5
Case report
Mixed epithelial and stromal tumor of the kidney with polypoid
component extending into renal pelvis and ureter
Masahiro Horikawa1, Hiroshi Shinmoto1, Kenji Kuroda2, Eisuke Shiomi1, Shigeyoshi Soga1,
Keiichi Ito2, Kazuyoshi Tachi2, Yuka Katsurada3, Hideyuki Simazaki3, Tomohiko Asano2 and
Tatsumi Kaji1
1Department of Radiology; 2Department of Urology; 3Department of Laboratory Medicine, National Defense Medical College, Saitama,
Japan
Correspondence to: Masahiro Horikawa. Email: [email protected]
Abstract
Mixed epithelial and stromal tumor (MEST) of the kidney is an unusual benign neoplasm that predominantlyoccurs in middle-aged females. It typically appears as a well-circumscribed multiseptate mass with
solid components on computed tomography (CT) or magnetic resonance image (MRI), reflecting its
characteristics of an admixture of stromal proliferation and epithelial cells consisting of multiple cysts. We
present a rare case of 61-year-old woman with MEST, which manifested as a multilocular cystic mass with a
polypoid component protruding into the renal pelvis and ureter. To our best knowledge, this is the first
case of MEST extending into the ureter.
Keywords: Mixed epithelial and stromal tumor, MEST, kidney, ureter, CT, MRI
Submitted October 26, 2011; accepted for publication November 24, 2011
Mixed epithelial and stromal tumor (MEST) is a rare, basi-cally benign neoplasm of the kidney that has recentlybeen recognized as a distinctive entity (1). It mostly occursin middle-aged women and is associated with estrogen exposure (2). The histological characteristic of MEST is an admixture of spindle cells resembling ovarian stroma andepithelial elements (1, 2). Approximately 100 cases havebeen reported in past literatures; however, most of thereports are focused on their pathologic features (2, 3).Reports of its radiologic characteristics, including computed
tomography (CT) and magnetic resonance imaging (MRI),have been still scarce (4–8). We present an unusual case of MEST of the kidney with a polypoid component extendinginto the renal pelvis and the proximal ureter.
Case report
A 61-year-old postmenopausal woman presented with grosshematuria for two weeks. The physical examination wasunremarkable. She had no relevant family history ormedical history other than mild obesity. Her routine bloodinvestigation was normal with no elevated serum tumor
marker. Ultrasonography revealed the presence of a left
renal mass in the interpolar region extending into the renalpelvis. Exfoliative urine cytology was class 3. Excretoryphase contrast-enhanced CT (Fig. 1a– c) showed a well-circumscribed multiseptate cystic mass of 44 Â 40 Â 45 mmin the interpolar region of the left kidney with a polypoidsolid component protruding into the renal pelvis and proxi-mal ureter. Calcification was identified within the solidcomponent. Retrograde ureterography (Fig. 1d) showedmild hydronephrosis due to the polypoid part of the tumorin the ureter. Dynamic MRI study (Figs. 2 and 3) demon-
strated delayed contrast enhancement of the solid polypoidcomponent and multiple septa.
Since the tumor was consistent with a Bosniak categoryIV cystic mass, we performed a laparoscopic left nephro-ureterectomy. Gross examination showed a well-marginatedmultilocular cystic mass with a polypoid solid componentprotruding into the renal pelvis and ureter (Fig. 4a).Histopathological analysis revealed an intermixture of epi-thelial elements consisting of varying sized glands and aproliferation of spindle cells resembling ovarian stroma.The polypoid lesion was superficially covered with normal urothelium. Complex glands with a single layer of flattened, cuboid or hobnail-appearing epithelium and a
mild cellular atypia of swollen nuclei were marked in the
Acta Radiologica Short Reports 2012;1:3. DOI: 10.1258/arsr.2011.110010
7/29/2019 mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
http://slidepdf.com/reader/full/mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm 2/5
Fig. 1 (a) Axial and (b, c) coronal excretory phase contrast CT showing a multilocular cystic mass with a polypoid part continuously extending into the pelvis and
ureter (white arrow); (d) Retrograde ureterography showing a polypoid tumor in the pelvis and proximal ureter and moderate hydronephrosis (white arrow heads)
Fig. 2 (a, b, c, d) Continuous slices of coronal T2-weighted MRI showing a well-circumscribed multiseptate cystic mass with a polypoid compartment extending
into the renal pelvis and proximal ureter
2 M Horikawa et al.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7/29/2019 mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
http://slidepdf.com/reader/full/mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm 3/5
Fig. 3 (a) Axial pre-enhanced, (b) axial arterial phase, (c) axial medullary phase fat-saturated T1-weighted MRI. Dynamic MRI study demonstrates delayed
enhancement in the polypoid lesion and septa; (d, e, f) Continuous coronal excretory phase fat-saturated T1-weighted MRI showing marked enhancement in
the polypoid lesion
Fig. 4 (a) Gross specimen showing a cystic lesion with septa and a sharply marginated solid polypoid lesion; (b) Photomicrograph of the polypoid lesion
showing proliferation of stroma, superficially covered with urothelium (black arrow) (hematoxylin and eosin stain;Â200); (c) Low-power-view and (d) high power-
view of the cystic lesion demonstrating an admixture of spindle cells resembling ovarian stroma and epithelial elements consisting of varying sized glands
(c, Â100; d, Â400; hematoxylin and eosin stain)
MEST of the kidney extending into the renal pelvis and ureter 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7/29/2019 mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
http://slidepdf.com/reader/full/mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm 4/5
7/29/2019 mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
http://slidepdf.com/reader/full/mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm 5/5
16 Turbiner J, Amin MB, Humphrey PA, et al. Cystic nephroma and mixedepithelial and stromal tumor of kidney: a detailed clinicopathologicanalysis of 34 cases and proposal for renal epithelial and stromal tumor(REST) as a unifying term. Am J Surg Pathol 2007;31:489–500
17 Zhou M, Kort E, Hoekstra P, et al. Adult cystic nephroma and mixedepithelial and stromal tumor of the kidney are the same diseaseentity: molecular and histologic evidence. Am J Surg Pathol2009;33:72–80
# 2012 The Foundation Acta RadiologicaThis is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc/2.0/), which permits non-commercial use, distribution and reproduction in any medium, provided the original
work is properly cited.
MEST of the kidney extending into the renal pelvis and ureter 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .