[1133] DPC4 Immunostaining in Mullerian Tumors with and without Mucinous Differentiation

Esther Elishaev, Xin Li, Amal Kanbour-Shakir, Sarah E Taylor, Robert P Edwards, Jing Yu, Anna H Woodard, Mirka W Jones, Rohit Bhargava. Magee-Womens Hospital of UPMC, Pittsburgh, PA

Background: Mucinous tumors in the ovary always raise a concern for a metastasis, and require a panel of immuno stains to determine site of origin. DPC4 immuno stain is always included in the diagnostic panel as the absence of staining for this antibody supports pancreatic origin of the tumor. While studies addressing DPC4 staining pattern in primary and metastatic mucinous tumors of pancreatic origin are well documented, knowledge of DPC4 in ovarian tumors or tumors of mullerian origin with or without mucinous differentiation is very limited. To address this issue, we stained tissue microarrays (TMAs) constructed from various mullerian and ovarian tumors with DPC4. In addition PAX8 was performed to ratify müllerian origin if DPC4 staining was negative.
Design: TMAs were constructed with three fold redundancy from various müllerian tumors with DPC4 results available on 37 endocervical adenocarcinomas, 55 endometrial and 113 ovarian tumors. An H score was used to evaluate both antibodies with negative interpretation for scores 0-10, and positive for 11-300.

DPC4 results
EC-usual type CA2 (11%)17 (89%)
EC-variant CA0 (0%)18 (100%)
EM-endometrioid CA1 (3%)38 (97%)
EM-non endometrioid CA1 (6%)15 (94%)
OV-endometrioid CA1 (8%)11 (92%)
OV-high grade serous CA0 (0%)21 (100%)
OV-clear cell CA4 (10%)35 (90%)
OV-mucinous CA0 (0%)2 (100%)
OV-serous BT0 (0%)19 (100%)
OV-mucinous BT0 (0%)16 (100%)
OV-seromucinous BT0 (0%)4 (100%)
EC:endocervix EM:endometrial OV:Ovary CA:carcinoma BT:borderline tumors

Of the 2 DPC4 negative endocervical carcinomas, one was also negative of PAX 8. Of the 2 DPC4 negative endometrial carcinomas, one was endometrioid and another clear cell and both were positive for PAX8. Of the 5 DPC4 negative ovarian tumors, 3 (1 endometrioid and 2 clear cell) were negative for PAX 8 and 2 (both clear cell) positive. Negative results for PAX 8 staining were seen in 46% of endocervical, 15% of endometrial, and 24% of ovarian tumors.
Conclusions: DPC4 can be negative in müllerian tumors with or without mucinous differentiation. Our study expands the list of DPC4 negative tumors from pancreato-biliary tract, and colo-rectal carcinomas to include common mullerian tumors. Caution is advised in interpreting loss of DPC4 as sine qua non for pancreatic carcinoma. If there is clinical and histologic suspicion of metastatic tumor in the ovary, it is best to perform an expanded panel that includes site specific markers in addition to different cytokeratins.
Category: Gynecologic & Obstetrics

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 205, Wednesday Afternoon


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