[1193] Frequency of Serous Tubal Intraepithelial Carcinoma in Various Gynecological Malignancies – A Study of 290 Consecutive Cases

S Tang, K Onuma, P Deb, E Wang, A Lytwyn, M Sur, D Daya. McMaster University, Hamilton, ON, Canada

Background: Serous tubal intraepithelial carcinoma (STIC) has been reported in association with 32%-46% of pelvic serous carcinoma, suggesting that the tubal fimbria is the primary source of ovarian and peritoneal serous carcinoma. We hypothesized that if this is the case, the frequency of STIC should be substantially lower in endometrial serous carcinomas, in non-serous gynecologic malignancies, and in benign gynecologic neoplasms than in ovarian or peritoneal serous carcinomas.
Design: From 2007-9 the fallopian tubes of 342 consecutive gynecologic cases (269 TAH-BSO, 21 BSO) were entirely submitted for histology using the Sectioning and Extensively Examining the FIMbriated end (SEE-FIM) protocol. This study included 290 of these cases (slides from 16 cases were not available for review and 36 cases only had 1 fallopian tube removed). The slides from the fallopian tubes were independently reviewed by two gynecologic pathologists who were blinded to all other findings; disagreements were resolved by a third pathologist.
Results:

FREQUENCY OF STIC IN SEROUS AND NON-SEROUS MALIGNANCIES

Primary Site	Carcinoma Type	Mean Age	No. Cases	No. (%) STIC
Ovary	Serous	66	33	6(18)
	Non-serous	56	14	0(0)
Endometrium	Serous	68	27	4(15)
	Non-serous	66	70	0(0)
Cervix	Serous	Not available	1	0(0)
	Non-serous	46	12	0(0)
Peritoneum	Serous	70	7	2(29)

STIC IN NON-GYNECOLOGICAL MALIGNANCIES AND OTHER CONDITIONS

Groups	Mean Age	No. Cases	No. (%) STIC
Non-gyn malignancies	54	15	0(0)
Benign conditions	53	87	0(0)
Other pathology*	50	24	0(0)

*4 cervical AIS and CIN III; 8 endometrial atypical complex hyperplasia; 12 ovarian borderline tumor.


Conclusions: STIC was present in 18%, 29%, and 15% of ovarian, peritoneal, and endometrial serous carcinomas, respectively. STIC was NOT identified in non-serous ovarian, endometrial and cervical malignancies, or other conditions. The fallopian tube may be the origin of some pelvic serous carcinomas. However, given that STIC coexisted with 15% of endometrial serous carcinomas, a more unifying theory may be that gynecologic serous carcinomas and STIC are multifocal lesions. Further studies are needed to elucidate the clinical significance of STIC and define the role of STIC in endometrial serous carcinoma.
Category: Gynecologic & Obstetrics

Tuesday, March 23, 2010 9:00 AM

Platform Session: Section D, Tuesday Morning