Mixed epithelial and stromal tumors of the kidney. A report of 22 cases.
Mixed epithelial and stromal tumor of the kidney (MESTK) is a recently described subset of renal neoplasm that tends to occur in middle-aged and older women and is characterized by a distinctive histological appearance. To further characterize this lesion, we report the clinicopathological and immunohistochemical features of 22 additional cases from our institutional files. Grossly, the tumors ranged in size from 1 cm to 14 cm (mean 6.7 cm), were well circumscribed but unencapsulated, and showed a cystic cut surface. The tumors were composed of a spindle cell proliferation that resembled ovarian stroma, as well as an epithelial component lining the cystic structures, which usually consisted of flat to hobnailed cells typical of collecting-duct epithelium. Areas displaying features of Mullerian differentiation were also documented in 6 cases, including epithelium of endometrioid, tubal, clear cell and squamous cell type as well as one case showing an architecture that closely resembled Mullerian adenofibroma and adenosarcoma. Follow-up in 14 patients (average 4.4 years) showed no evidence of recurrence or metastasis. We believe these tumors represent the renal counterpart of similar mixed epithelial and stromal neoplasms occurring in the biliary tract and pancreas, which is also characterized by cystic structures lined by epithelium, admixed with ovarian-type stroma. The differential diagnosis for these tumors includes cystic nephroma and cystic partially differentiated nephroblastoma, which we believe to represent clinically and morphologically distinct entities from MESTK. In particular, the distinction from cystic nephroma in adult male patients is emphasized, and two cases of this entity are included in the study for comparison.
Sikl's Department of Pathology, Laboratore Spec. Diagnostiky Medical Faculty Hospital, Charles University Hospital, Alej Svobody 80, 30460 Pilsen, Czech Republic. michal@medima.cz
Michal
M
Michal
Ondrej
O
Hes
Michele
M
Bisceglia
Roderick H W
RH
Simpson
Dominic V
DV
Spagnolo
Alberto
A
Parma
Ludmila
L
Boudova
Milan
M
Hora
Roman
R
Zachoval
Saul
S
Suster
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018193:Neoplasms, Complex and Mixed / Q000473:pathology*; D009375:Neoplasms, Glandular and Epithelial / Q000473:pathology*; D017154:Stromal Cells / Q000473:pathology