Japan-Korea-Taiwan GYN Conferece
Mini Lecture

Seromucinous Tumor
Yoshiki Mikami, M.D., Ph.D.
Department of Diagnostic Pathology
Kumamoto University HospitalWHO2003

WHO2014

Mucinous tumors

Mucinous tumors

Intestinal

Endocervical-like

BenignBenignBorderline

Borderline

Malignant

MalignantBorderline

Seromucinous
tumorsBenignBorderline
Malignant3Overview• General understanding• Controversies–Discussion4

Seromucinous borderline tumor• Unilocular or
oligolocular• Granular or papillary
excrescences• Viscid and/or
purulent material• Frequently bilateral(40%) and a/w
endometriosis (50%)
5Seromucinous borderline tumor• Microscopicfeatures
 Architecturally
resembling SBT
 Wide papillae
showing hierarchicalbranching6

7Seromucinous borderline tumor• Microscopicfeatures
 Cytology• Mucinous cells• Ciliated cells

8Seromucinous borderline tumor• Microscopic
features Cytology• Mucinous cells• Ciliated cells

9Seromucinous borderline tumor• Microscopicfeatures
 Cytology• Mucinous cells• Ciliated cells• Indifferent cells

10Implants

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Implants

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Implants

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Implants（desmoplastic）

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Implants（desmoplastic）

15Seromucinous
cystadenoma / adenofibroma

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Seromucinous borderline tumor
with intraepithelial carcinoma

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Seromucinous carcinoma

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Overview• General understanding• Controversies–Discussion

29Normal endocervical glands

30Normal endocervical glands

31NormalEndocervical gland

Seromucinous32

Endocervical-like mucinous
borderline tumor• Ovarian tumors of low malignant
potential exhibiting an epithelial
proliferation of mucinous type cells
greater than seen in their benign
counterparts but without destructive
stromal invasion• The mucinous epithelial cells resemble
endocervical epithelium
WHO2003

Seromucinous borderline tumor• Non-invasive proliferative tumor
composed of more than one types
of epithelial cells• Predominantly serous andendocervical types• Occasionally admixed withendometrioid, clear cell, andsquamous epithelium
WHO2014

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Seromucinous borderline tumor
Synonyms• Endocervical-like MBT• Müllerian MBT• Borderline müllerian tumor
WHO2014

Seromucinous borderline tumor
Name“Seromucinous”

Morphology
EndocervicalWHO2014

Definition

Mixed müllerian414243

Seromucinous borderline tumor

44Seromucinous borderline tumor

Endocervical type

Serous type
Endometrioid type
Clear cell typeSquamous type
(Transitional type)! No strict quantitative criteria
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Seromucinous borderline tumor

Seromucinous ????

Serous type
Endometrioid type
Clear cell typeSquamous type
(Transitional type)

Endocervical type

! No strict quantitative criteria
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Seromucinous borderline tumor
KRAS mutation(Kim KR et al,2010)
Similar toendometrioidtumors

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Seromucinous borderline tumor
ER/PR＋WT1－
CK20－、CDX2－
ARID1A mutation(Kurman et al. 2016)

Similar toendometrioid orclear cell tumors
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Seromucinous Tumors of the Ovary
What’s in a Name ?
Kurman RJ and Shih I-M. Int J Gynecol Pathol 2016; 35: 78-81… Based on their clinicopathologic,
immunohistochemical and molecular genetic
features we believe a more appropriate
designation for this group of tumors is "mixedmüllerian tumors" which can be subcategorized as"mixed müllerian cystadenomas", "mixed müllerian
atypical proliferative (borderline) tumors" and"mixed müllerian carcinomas".
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Seromucinous carcinoma

Vs Endometrioid carcinoma withmucinous differentiation

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Seromucinous carcinoma

Background

Seromucinous borderline tumor

Endometrioid carcinoma
with mucinous
differentiation

Prototypical endometrioid
carcinoma52• Seromucinous carcinoma
may be reclassified to
endometrioid, low-grade
serous, and mucinous
carcinomas by integrating
morphology,immunophenotype, andgenotype.
• the category ofseromucinous carcinoma
be discontinued asancillary molecular tests
can assign cases to oneof the major histotypes
Rambau PF, et al. Am J Surg Pathol. 2017;41: 685-695.

53• Seromucinous carcinomamay be reclassified to
endometrioid, low-grade
serous, and mucinous
carcinomas by integrating
morphology,
immunophenotype, andgenotype.
• the category ofseromucinous carcinoma
be discontinued asancillary molecular tests
can assign cases to oneof the major histotypes
Rambau PF, et al. Am J Surg Pathol. 2017;41: 685-695.

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Mucinous
LG Serous

1/32 (3%)

8/32 (25%)

LG-ndometrioid
23/32 (72%)"SEROMUCINOUS
CARCINOMA"• Seromucinous carcinoma
may be reclassified to
endometrioid, low-grade
serous, and mucinous
carcinomas by integrating
morphology,
immunophenotype, andgenotype.
• the category ofseromucinous carcinoma
be discontinued asancillary molecular tests
can assign cases to oneof the major histotypes

Rambau PF, et al. Am J Surg Pathol. 2017;41: 685-695.

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Thank you foryour attention
Yoshiki Mikami, M.D.
Kumamoto University Hospitalmika@kuhp.kyoto-u.ac.jp

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