Fallopian tubes & broad ligament
Fallopian tube tumors
Serous tubal intraepithelial carcinoma
Authors: Aysha Mubeen, M.D., Arun Gopinath, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Topic Completed: 10 July 2019
Minor changes: 30 December 2020
Copyright: 2019-2021, PathologyOutlines.com, Inc.
PubMed Search: Serous tubal intraepithelial carcinoma[TI]
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Clinical features | Diagnosis | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Mubeen A, Gopinath A. Serous tubal intraepithelial carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/fallopiantubesstic.html. Accessed January 24th, 2021.
Definition / general
- Lesion limited to the fallopian tube epithelium that is a precursor to extrauterine (pelvic) high grade serous carcinoma
Essential features
- Confined to epithelium
- Histologic features: high proliferative index, significant atypia, architectural alterations and strong staining for p53
- Especially important precursor lesion that is a criterion for assigning fallopian tube as primary site of high grade tubo-ovarian serous carcinoma irrespective of presence and size of ovarian and peritoneal disease (Histopathology 2015;67:331)
Terminology
- Various terms used in tubal epithelial alterations are:
- Secretory cell outgrowths (SCOUTs): secretory cell expansion with variable ciliation
- p53 signature or serous tubal intraepithelial lesions (STILs): secretory cell outgrowths with strong p53 staining (normal histology)
- Serous tubal intraepithelial carcinoma (STIC): abnormal histology (high N:C, loss of polarity, lack of ciliated cells, strong and diffuse p53 or rarely completely negative)
ICD coding
- ICD-10: N83.9 - fallopian tube disorder
Epidemiology
- Patients with hereditary BRCA mutation have a high risk of ovarian serous cancer
- Incidence of STIC in risk reducing salpingo-oophorectomies in BRCA+ women is 5 - 8% (Gynecol Oncol 2006;100:58)
Sites
- Fallopian tube fimbria is the most common site of origin
Pathophysiology
- Secretory epithelium is postulated as the cell of origin (Adv Anat Pathol 2010;17:293)
Clinical features
- Usually discovered incidentally during routine surgery or risk reducing prophylactic salpingo-oophorectomies
- May be seen adjacent to invasive carcinoma
Diagnosis
- Examination of tissue is required for the diagnosis; cannot be made with immunostains alone
- Gross protocol influences ability to diagnose
- Amputation and longitudinal sectioning of the infundibulum and fimbrial segment (distal 2 cm) allows maximal exposure of the tubal plicae; isthmus and ampulla are cut transversely at 2 - 3 mm intervals
- Entire fallopian tube should be submitted for evaluation in women with BRCA mutations or strong family history of ovarian carcinoma
- Extensively examine the fimbriated end
- Controversial role of multiple levels with 1 study finding no impact (Am J Surg Pathol 2009;33:1878) and a newer study reporting 25% missed with a single section (Int J Gynecol Pathol 2013;32:353)
Case reports
- 48 year old woman with STIC in cervical smears (Diagn Cytopathol 2018;46:945)
- 51 year old postmenopausal woman with STIC and BRCA1 mutation (Jpn J Clin Oncol 2014;44:597)
- 55 year old woman with synchronous papillary serous carcinoma of ovary and endometrium and STIC (Indian J Pathol Microbiol 2017;60:125)
- 56 year old woman with incidental STIC (Case Rep Obstet Gynecol 2015;2015:760429)
- 58 year old woman with retroperitoneal high grade serous carcinoma and STIC (Diagn Pathol 2019;14:17)
Treatment
- No current consensus among gynecologic oncologists regarding appropriate management of incidental STIC
- Patients have been managed by surgical staging / peritoneal washings / chemotherapy or followup without additional intervention
- Yield of surgical staging is low and short term clinical outcomes are favorable
- Individualized management is warranted until additional data become available (Int J Gynecol Cancer 2013;23:1603)
Gross description
- Not evident on gross examination
Microscopic (histologic) description
- Basophilic appearance
- Epithelial stratification
- Lack of ciliated cells (Mod Pathol 2017;30:710)
- High N:C ratio
- Nuclear pleomorphism and hyperchromasia
- Loss of polarity (may be focal)
- Epithelial fractures (Adv Anat Pathol 2010;17:293)
Microscopic (histologic) images
Contributed by Aysha Mubeen, M.D.
Basophilic appearance
Architectural and cytological atypia
STIC in contrast with adjacent normal tubal epithelium
Prominent atypia and multilayering
p53
Cytology description
- Brush cytology shows clusters of cells with haphazard pleomorphic nuclei, high N:C ratio and lack of cilia (Cancer Cytopathol 2019;127:192)
Positive stains
Molecular / cytogenetics description
- Mutations in the p53 tumor suppressor gene that retard degradation of the protein product (J Pathol 2019;248:41)
Sample pathology report
- Bilateral fallopian tubes, salpingectomy:
- Right fallopian tube with serous tubal intraepithelial carcinoma (see comment)
- Left fallopian tube with no pathologic change
- Comment: Immunostain for p53 is diffusely and strongly positive in the lesional cells. Ki67 index is > 40%.
Differential diagnosis
- p53 signature: precursor lesion which appears benign and lacks atypia on histology with p53+ immunostain
- Transitional cell metaplasia: uniform cells with nuclear grooves, p53-
- Florid epithelial hyperplasia and reactive atypia associated with acute salpingitis: has a background of inflammation, retained polarity and presence of ciliated cells
Additional references
- Front Biosci (Elite Ed) 2011;3:625, Int J Gynecol Pathol 2010;29:310, Mod Pathol 2009;22:985, Curr Opin Obstet Gynecol 2007;19:3, Adv Anat Pathol 2006;13:1, CAP: Protocol for the Examination of Specimens from Patients with Primary Tumors of the Ovary, Fallopian Tube or Peritoneum [Accessed 4 June 2019]
Board review style question #1
What is the name of a lesion that appears normal on histology but stains positive for p53 immunostain?
- p53 signature
- Reactive atypia
- Secretory cell outgrowth (SCOUT)
- Serous tubal intraepithelial carcinoma (STIC)
Board review style answer #1
Board review style question #2
The grossing protocol for examination of the fallopian tube to identify the diagnosis in the photomicrograph should
- Ensure complete evaluation of the fallopian tube in all cases
- Increase detection of precursor lesions in at risk women
- Require multistep levels in at risk women
- Require tangential sectioning of the infundibulum and fimbrial segment to allow maximal exposure
Board review style answer #2
B. Increase detection of precursor lesions in at risk women. Serous tubal intraepithelial carcinoma is shown in the photomicrograph.
Reference: Serous tubal intraepithelial carcinoma
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Reference: Serous tubal intraepithelial carcinoma
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