Coexistence of Ectopic Tubal Pregnancy with Serous Tubal Intraepithelial Carcinoma: A Rare Case Report with Review of Literature.

A 31-year-old female was operated for the right ectopic tubal gestation in a private hospital. She underwent laparoscopic salpingectomy. Surgical specimens of multiple pieces of the right fallopian tube were received for histopathological examination [ Figure 1a ]. They were swollen and external surface was congested. On cut section, black–brown firm tissue was seen measuring 1.5 cm × 1.5 cm. Narrowed lumen of the fallopian tube could be identified at fimbrial end. (a) Black pieces of fallopian tube, (b) serous tubal intraepithelial carcinoma (H and E, ×100) Multiple sections were taken for histopathology examination. Sections were fixed in formalin and paraffin processed. Two to four thick micron sections were cut and stained with haematoxylin and eosin (H and E). Sections from grey–brown firm area showed blood clot, chorionic villi, decidua and occasional trophoblastic cells. Sections from fimbrial end showed marked hyperplasia and stratification of non-ciliated columnar epithelium with loss of polarity of cells [ Figure 1b ]. Nuclei showed moderate nuclear enlargement with many showing prominent nucleoli. Mitotic figures were increased with occasional atypical mitotic figure [Figure 2a and b ]. Muscular propria and serosa were free from invasion by epithelial cells. A diagnosis of STIC was suggested. (a and b) Enlarged nuclei and increased mitotic figures (H and E, ×400), (c) diffuse p53 immunostaining (IHC, ×100), (d) High ki67 labelling index (IHC, ×100) Immunohistochemical (IHC) staining with p53 showed a strong diffuse nuclear positivity with variable cytoplasmic staining [ Figure 2c ]. Ki 67 labelling index was very high of about 60% [ Figure 2d ]. A final histopathology diagnosis of STIC was made. Subsequent imaging studies did not show any lesion in the pelvic organs or evidence of ascites. Subsequent genomic analysis of the patient did not reveal BRCA-1,2 mutations. None of the immediate relatives of the patient gave a history of any pelvic organ carcinomas or carcinoma at the other sites.

Serous tubal intraepithelial carcinoma (STIC) is a non-invasive carcinoma of the fallopian tube. It is most commonly found in women with germline BRCA-1,2 mutations. Carriers of these mutations have a higher risk of developing breast, ovarian and peritoneal carcinoma.[ 1 2 ] It is thought to be the earliest known manifestation of most pelvic serous carcinoma.[ 3 ] STIC in women who do not have BRCA-1,2 mutations or concomitant high-grade serous carcinoma is exceedingly rare. STIC coexisting with ectopic tubal gestation or tubal leiomyoma, adenofibroma and adenomatoid tumour is very rarely reported.[ 4 5 ] We report one such case of a 31-year-old female who was operated for the right tubal gestation and found to have serous tubal intraepithelial carcinoma.

STIC in women without BRCA-1,2 mutations or concomitant high-grade serous carcinoma is extremely rare. A combination of histology and immunohistochemical expression pf p53 and ki67 substantially improves the reproducibility of the diagnosis. Extensive sampling of fallopian tubes is necessary for identifying these lesions. Diagnosing these lesions will help identify potential at risk patients and their families for carcinoma. Adequate prolonged follow-up for incidental STIC is the mainstay. The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Nil. There are no conflicts of interest.

STIC is a rare pathologic finding in fallopian tube at the time of benign gynaecologic surgery. It is an abnormal growth of stratified non-ciliated cells. It is associated with 50%–60% of high-grade serous pelvic carcinomas and discovered in 5-10% of asymptomatic BRCA-1,2 mutation carriers.[ 6 7 8 ] The STIC usually arises in the tube when it is unilateral and shows variable atypia of low-grade to high-grade and absent advanced disease. In our case, there was evidence of invasive tubal carcinoma or other neoplastic lesion in pelvic cavity. It less likely arises from the tube when it is bilateral and the lesion shows marked atypia and evidence of advanced endosalpingeal neoplasm.[ 1 ] STIC coexisting with tubal leiomyoma, adenofibroma and adenomatoid tumour has been rarely reported in the literature.[ 4 ] Coexistence of ectopic tubal gestation with STIC is extremely rare. Possible reason for the tubal gestation may be due to partial obstruction of tube by STIC. These lesions are usually found in the distal part of the fallopian tube, most commonly in the fimbrial part. They pose considerable difficulty in the diagnosis. Carlson et al . stated that the diagnosis of STIC is not optimally reproducible only by histological examination.[ 9 ] A combination of histopathology and immunohistochemical expression of p53 and Ki67 substantially improves the reproducibility of the diagnosis and differentiating it from other proliferative lesions of the fallopian tube, especially from serous tubal intraepithelial lesion (STIL). In STIC, there is aberrant p53 expression and increased Ki67 immunostaining of more than 15% of cells.[ 10 ] Aberrant p53 expression can be either disuse strong positivity or absent immunostaining due to non-sense mutation. STIL shows p53 expression and ki67 staining falling short of full criteria for STIC.[ 10 ] Diagnosis of STIC has important management implications when it is found in fallopian tubes removed from women with a strong family history of ovarian cancer or women who have germline mutations of BRCA-1,2. STIC if unassociated with invasion or extra tubal disease, follows benign course. Few exceptions have been reported.[ 10 ] Very rarely, they have been associated with transcoelomic spread and stage III disease. Hence, more studies are required to refine diagnostic criteria for atypical intermediate lesions such as STIL and intraepithelial lesions in transition.