PMC3355654_01
Magnetic resonance imaging showing a 7.8-cm cystic lesion of the presacral area.
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F1
An image study was conducted which disclosed a large presacral cyst, measuring 7.8 x 7 x 5.4 cm in its greatest dimension (fig. 1).
Presacral lesion showing teratomatous components including gastrointestinal epithelium (a), cartilage (b), and respiratory epithelium (c). Transition between the respiratory epithelium of the teratoma and the dysplastic epithelium of the adjacent adenocarcinoma (d).
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F2
Microscopic examination of the anterior resection specimen revealed a teratocarcinoma composed of mature cystic teratoma and adenocarcinoma (fig. 2d, fig. 3a). The teratoma component of the teratocarcinoma consisted of gastrointestinal mucosa (fig. 2a), cartilage (fig. 2b), pseudostratified respiratory epithelium (fig. 2c), and pancreas tissue.
Juxtaposition between the benign ciliated pseudostratified columnar epithelium (R) and the dysplastic epithelium (D) of the adenocarcinoma was identified in both the presacral teratocarcinoma (a) and the original rectal adenocarcinoma (a inset). The respiratory epithelium (R) shows CK7+CK20-CDx2- immunophenotype (b-d), and the dysplastic epithelium (D) of the adenocarcinoma shows CK7+/-CK20+CDx2+/- immunophenotype (b-d). The dysplastic epithelium (D) of the original rectal cancer shows more intense CDX2 staining (d inset).
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F3
Juxtaposition of the pseudostratified respiratory epithelium of the teratoma and the neoplastic cells of the adenocarcinoma was identified (inset in fig. 3a). By immunohistochemistry, the neoplastic cells of the adenocarcinoma were negative for cytokeratin-7 (CK7) and positive for CK20 (CK7-CK20+) (fig. 3b, c). The adjacent juxtaposed respiratory epithelium had immunophenotype of CK7+CK20- (fig. 3b, c). The result of the immunohistochemistry stain for caudal related homeodomain transcription 2 (CDX2) was positive in the neoplastic cells of the adenocarcinoma but negative in those of the adjacent respiratory epithelium (fig. 3d).