PMC3119391_01
Haematoxylin und eosin staining of the appendix carcinoma. The mucinous lakes constitute more than 50% of the tumor mass which is a criterion for the mucinous type of the appendiceal carcinoma.
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F1
The histopathological examination of the specimen surprisingly revealed a pT4a (local infiltration of the visceral peritoneum) mucinous adenocarcinoma of the appendix (figure 1) with positive resection margins (R1 resection).
Immunhistochemical staining of the tumor. The blue colored cores as a sign of loss of expression of MLH1. The red colored cores show normal expression of MLH1.
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F2
Immunhistochemical examination showed a lack of expression of the two mismatch repair genes MLH1 (figure 2) and MSH2 (figure 3) possibly associated with hereditary non-polyposis colon cancer syndrome (HNPCC or Lynch syndrome).
Immunhistochemical staining of the tumor. The blue colored cores as a sign of loss of expression of MSH2. The red colored core in the center shows normal expression of MSH2.
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F3
Immunhistochemical examination showed a lack of expression of the two mismatch repair genes MLH1 (figure 2) and MSH2 (figure 3) possibly associated with hereditary non-polyposis colon cancer syndrome (HNPCC or Lynch syndrome).
PCR amplification of the repetitive DNA sequences D2S123 (A), D5S346 (B) and D17S250 (C). The upper sequences show the traces of the reference-DNA gained from peripheral blood. The lower sequences show the traces of the tumor tissue. Differences are marked by red arrows.
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F4
Analysis of microsatellite instability (MSI) showed high grade MSI (MSI-H) testing the markers BAT25 (stable), BAT 26 (stable), D2S123 (instable), D5S346 (instable) and D17S250 (instable) (figure 4).