Fallopian tubes & broad ligament
Fallopian tube tumors
Serous tubal intraepithelial carcinoma
Authors: Aysha Mubeen, M.D., Arun Gopinath, M.D.
Editorial Board Member: Gulisa Turashvili, M.D., Ph.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Last author update: 20 April 2022
Last staff update: 20 April 2022
Copyright: 2019-2022, PathologyOutlines.com, Inc.
PubMed Search: Serous tubal intraepithelial carcinoma
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 | Virtual slides | Cytology description | Positive stains | 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 December 9th, 2022.
Definition / general
- Lesion that is limited to the fallopian tube epithelium and a precursor to extrauterine (pelvic) high grade serous carcinoma
Essential features
- Confined to epithelium
- Histologic features: significant atypia, architectural alterations, high proliferative index and mutant pattern of p53 staining
- Important precursor lesion to recognize, as it 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 to describe a spectrum of tubal epithelial alterations:
- Secretory cell outgrowths (SCOUTs): secretory cell expansion with variable ciliation (type 1 / tubal differentiation and type 2 / endometrioid differentiation), wild type p53 staining
- p53 signature: histologically normal epithelium (at least 12 cells) with mutant pattern p53 staining and low proliferation index (MIB1) (typically less than 10%)
- Serous tubal intraepithelial lesion (STIL): abnormal histology (high N/C but preserved polarity), mutant p53 and variable MIB1; STIL is regarded as a lesion of uncertain significance and diagnostic features fall short of STIC
- Serous tubal intraepithelial carcinoma (STIC): abnormal histology (high N/C, loss of polarity, lack of ciliated cells), mutant pattern p53 staining and high proliferation index (MIB1)
ICD coding
- ICD-10: N83.9 - fallopian tube disorder
Epidemiology
- Patients with hereditary BRCA mutation have a high risk of high grade serous carcinoma
- 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 of fallopian tube 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
- Reference: Gynecol Oncol 2017;146:69
Diagnosis
- Careful morphologic evaluation is key to the diagnosis; immunohistochemistry (p53 and MIB1) is only supportive
- Gross protocol (sectioning and extensively examining the fimbria [SEE-FIM]) influences ability to diagnose (Am J Surg Pathol 2006;30:230):
- 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 and another study reporting 25% missed with a single section (Am J Surg Pathol 2009;33:1878, Int J Gynecol Pathol 2013;32:353)
- STIC is staged as pathologic stage pT1
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 follow up 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
- Epithelial stratification
- Lack of ciliated cells (Mod Pathol 2017;30:710)
- High N/C ratio
- Nuclear pleomorphism, hyperchromasia, prominent nucleoli
- Loss of polarity (may be focal)
- Epithelial fractures (Adv Anat Pathol 2010;17:293)
- Exfoliation of small epithelial clusters
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
Virtual slides
Images hosted on other servers:
Focal epithelial stratification,
loss of polarity,
hyperchromatic and
pleomorphic nuclei
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
- p53: mutant pattern of staining (diffusely positive (nuclear), completely negative (null type) or less commonly, cytoplasmic staining)
- Ki67 / MIB index: high (suggested cutoff of 10%) (Am J Surg Pathol 2011;35:1766, Int J Gynecol Pathol 2012;31:243)
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 > 10%.
Differential diagnosis
- p53 signature:
- Precursor lesion which shows normal histology with p53 mutant pattern of staining
- Transitional cell metaplasia:
- Uniform cells with nuclear grooves; p53 wild type (Am J Surg Pathol 2009;33:111)
- Florid epithelial hyperplasia and reactive atypia associated with acute salpingitis:
- Has a background of inflammation, retained polarity and presence of ciliated cells; p53 wild type
- Intramucosal fallopian tube metastasis from uterine serous carcinoma:
- May closely mimic STIC; usually WT1 negative (Am J Surg Pathol 2017;41:161)
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 5 January 2022]
Board review style question #1
Which fallopian tube lesion appears normal on histology but shows a mutant pattern of p53 immunostaining?
- 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.
Comment Here
Reference: Serous tubal intraepithelial carcinoma
Comment Here
Reference: Serous tubal intraepithelial carcinoma
