Case Report
Increased Serum Inhibin Associated with Ovarian Fibroma Neoplasms
Copeland KP, Cosgrove CM, Fowler JM and Copeland LJ*
Department of Obstetrics and Gynecology, Ohio State University, USA
*Corresponding author: Larry J. Copeland, Department of Obstetrics and Gynecology, The Ohio State University Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, 320 West 10th Avenue, M-210 Starling Loving Hall, Columbus, Ohio 43210, USA
Published: 20 Jun, 2016
Cite this article as: Copeland KP, Cosgrove CM, Fowler
JM, Copeland LJ. Increased Serum
Inhibin Associated with Ovarian
Fibroma Neoplasms. Clin Oncol. 2016;
1: 1019.
Abstract
Background: Clinicians are commonly tasked to evaluate adnexal masses. Both radiography and
serum markers are useful in the counseling of patients regarding management options. Inhibin is
one of several tumor markers used in the evaluation of adnexal masses given its known association
with sex cord stromal tumors, specifically granulosa cell tumors.
Case 1: 68 year old G6P6 Caucasian female who initially presented to her provider with postmenopausal
bleeding; work up demonstrated a complex adnexal mass and a serum Inhibin B level
of 277 (normal < 10). She underwent a hysterectomy and bilateral salpingo-oophorectomy with final
pathology returning as a benign fibroma.
Case 2: 38 year old G2P1011 African American female who presented to the emergency department
for abdominal pain; a pelvic ultrasound demonstrated a complex left adnexal mass. Serum tumor
markers included an Inhibin B of 719 (normal <139). An ovarian cystectomy was performed and
pathology returned as a cystadenofibroma.
Discussion: In these two patients, granulosa cell tumor was suspected initially as both had markedly
elevated inhibin B levels in the setting of an adnexal mass. Both patients were counseled on the
need for surgery and possibility of surgical staging. However, for each patient, frozen section
demonstrated benign fibromas. In Case 2, we were able to preserve ovarian tissue given the desire
for future fertility. Both cases demonstrate that while tumor markers can be helpful in providing
additional information in the evaluation of adnexal masses, they are not diagnostic tests and surgical
management is the only means for a diagnosis.
Introduction
Adnexal masses are common; in fact, 5-10% of women undergo surgery for an adnexal mass in
their lifetime [1]. In the primary evaluation of an adnexal mass, radiographic appearance and tumor
markers may assist the clinician in determining a possible diagnosis. Radiographic appearance
characterizes adnexal masses – size, complexity of the mass, and the presence of ascites should be
noted for assistance management strategy – surgery or observation [2] and preferred provider–
general gynecologist or gynecologic oncologist. Tumor markers and family history can be a helpful
adjunct in management decisions. While there is no tumor marker that is sensitive or specific
enough to be used as a screening tool, often case-specific clinical information and characteristics
of the adnexal mass can help guide clinicians as to which serum tumor marker(s) may be clinically
useful [3].
Tumor markers differ based on cell type and multiple serum tumor markers are used for
assessing adnexal pathology [4]. Inhibin is a tumor marker associated with sex cord stromal tumors,
specifically granulosa cell tumors. These tumors may also produce estradiol, which often correlates
with the symptoms of hyperestrogenism, including abnormal uterine bleeding, and may also be
associated with endometrial cancer [5,6].
Case 1
68 year old G6P6 Caucasian female who presented to her provider with a 10 day history of
light post-menopausal vaginal bleeding, the patient denied bladder or bowel issues, weight loss,
and abdominal pain or bloating. Her past medical history included well controlled hypertension.
She had a remote history of an abnormal pap smear. She had been menopausal since the age of 48
and menarche was age 14. Her obstetrical history included six vaginal deliveries. Surgical history
was non-contributory. Her family history included a sister with breast cancer and a brother with
esophageal cancer.
A gynecological exam included a normal vagina and cervix on
speculum exam, uterus was normal shape and size on bimanual.
Her adnexa on bimanual and rectovaginal examinations were noted
to have fullness on the left side, there was no cul de sac nodularity
noted. A pelvic ultrasound demonstrated a thickened endometrial
lining (13.8 mm, normal <4 mm) and a complex left adnexal mass
(7 x 5.3 x 5.9 cm). An endometrial biopsy was performed that was
negative for malignancy or hyperplasia. Serum tumor markers were
obtained and demonstrated an elevated Ca-125 (63.7, normal <35),
elevated Inhibin B (277, normal < 10) and mildly elevated Inhibin A
(7.7, normal < 6.9).
She underwent a total abdominal hysterectomy, bilateral salpingooophorectomy
with an intra-operative frozen section. Frozen section
was consistent with an ovarian stromal tumor favoring fibroma and
final pathology confirmed the diagnosis. Pathological exam included
an 8.8 x 5.6 x 5.4 cm ovarian mass focally multinodular external
appearance with whorled rubbery tissue and no hemorrhage or
necrosis. No immunohistochemical testing was performed given the
histological appearance of the specimen (Table 1).
No further treatment was required. Four months post-op the
patient had repeat Ca -125 and Inhibin B levels tested both of which
had normalized 5 and <10, respectively
Table 1
Case 2
38 year old G2P1011 African American female who presented
to the emergency department with a two day history of left sided
abdominal pain – she had an ultrasound performed and was
discharged with referral to gynecology. The pelvic ultrasound
demonstrated a complex left adnexal mass (7.8 x 8.1 x 8.5 cm).
The patient had a past medical history of well controlled
hypertension and obesity. Her surgical history included a right
salpingo-oophorectomy for an ectopic pregnancy. Her mother was
reported to have a questionable history of a gynecological malignancy.
She had a history of a vaginal delivery and no other gynecological or
obstetrical issues. She underwent menarche at the age of 9.
At her follow up appointment with gynecology her previous
records were reviewed and it was noted that this adnexal mass had
been present and stable for the last 3 years. The patient desired
future fertility and had concerns about the possibility of losing her
remaining ovary. She denied bladder or bowel issues and abnormal
uterine bleeding but did note she had lost about 10 pounds over the
preceding couple of months. Her gynecological exam demonstrated
a normal vagina and cervix on speculum exam. Her bimanual was
limited given her habitus but no abnormalities were appreciated.
Tumor markers collected 3 years prior were normal. Follow up tumor
markers collected demonstrated a normal Alpha-Fetal-Protein (AFP)
(1.8, normal <8.5), normal Ca-125 (14, normal <35), normal Ca 19-9
(31, normal <37), normal Inhibin A (6.8, normal <97) and a markedly
elevated Inhibin B (719, normal <139). Given the elevated Inhibin B
levels in conjunction with an adnexal mass, the concern for a granulosa
cell tumor was discussed with the patient. Given her desired fertility,
an ovarian cystectomy was discussed with the plan for a completion
oophorectomy and surgical staging if a malignancy was found.
A cystectomy was performed with frozen section consistent with
serous cystadenofibroma which was confirmed on final pathology.
The cyst was to be 9.8 x 7.9 x 6.7 cm and upon sectioning no areas
of nodular induration or papillary excrescences were identified. No
immunohistochemical testing was performed given the histologic
appearance of the specimen.
No further therapy was required and the patient did not have a
follow up Inhibin drawn.
Discussion
Sex cord stromal tumors
Sex cord stromal tumors (SCST) are a heterogeneous group of
tumors originating from the ovarian stroma surrounding oocytes.
They make up a variety of benign and malignant tumors [7]. SCST
compose 8% of all ovarian tumors and include granulosa, SertoliLeydig,
theca, nonspecific gonadal stromal cell, and single or mixed
types of tumors [8-10]. SCST are also heterogeneous in their ability to
produce steroids or other hormones [11].
As previously mentioned, the hormone (specifically inhibin B)
producing capacity of GCT has already been established [12]. GCT
are typically steroidogenic, secreting estrogen in supra-physiologic
amounts 70% of the time. Granulosa cell tumors are the most
common of the malignant SCST, accounting for 5-10% of all ovarian
malignancies [8,13,14].
Sex cord stromal tumors composed of pure ovarian stroma
are typically solid benign tumors, and over 50% are fibromas [11].
Ovarian fibromas and fibrothecomas are uncommon, accounting for
only 1-5% of ovarian tumors [15-17]. The risk of malignancy with a
solid ovarian tumor is 8.7%, therefore, surgical removal of all solid
ovarian tumors is universally recommended [18].
Inhibin as a tumor marker
Inhibin is a tumor marker for gynecologic malignancy, often
elevated in both granulosa cell tumors (GCT) and mucinous
cystadenocarcinomas [8,19,20]. As a tumor marker for GCT, inhibin
is thought to be reliable as levels decrease following surgery, increase
with recurrence, and magnitude directly correlates with tumor
size [11,21,22]. Inhibin is a less reliable ovarian tumor marker in
premenopausal women, as inhibin levels vary with the menstrual
cycle, reflecting the varying levels of FSH [23,24]. Inhibin peaks midcycle
and during the luteal phase, at which time levels are high enough
to make it difficult to detect potential excess inhibin production from
a tumor [9]. In postmenopausal and surgically castrated women,
inhibin levels are normally undetectable since the ovarian tissue is
less functional in the production of estrogen in these two patient
populations, making it a more reliable tumor marker in those clinical
situations [25]. The primary source of inhibin production in the
non-pregnant woman is the ovary [26]. Other minor sites of inhibin
production include the pituitary, adrenal gland, and the placenta
during pregnancy [13].
Conclusion
Adnexal masses are a common source of referral for gynecological
oncologists. The use of serum tumor markers assists physicians in
counseling and operative planning in these patients. Tumor markers
are additionally useful in following response to treatment. In the
counseling of patients with adnexal masses and elevated inhibin
levels the risk of a granulosa cell malignancy must discussed. Patients
at risk for malignancy should receive pre-operative counseling that
comprehensive surgical staging may be indicated. Patients must also
be counseled that if malignancy is encountered adjuvant therapy with
chemotherapy may be indicated. Patients must also be counseled
that while suspicion may be high for malignancy that the diagnosis
can only be made after surgery and that a benign inhibin secreting
adnexal mass is possible.
In these two patients, the diagnosis of granulosa cell tumor was
suspected initially as both had markedly elevated inhibin B levels in
the setting of an adnexal mass. In Case 1, the patient additionally
had symptoms that could be attributable to hyperestrogenism. Both
patients were counseled on the need for surgery and possibility
of surgical staging. However, for each patient, frozen section
demonstrated benign fibromas. In Case 2, we were able to preserve
ovarian tissue given the desire for future fertility. Both cases
demonstrate that while tumor markers can be helpful in providing
additional information in the evaluation of adnexal masses, they
are not diagnostic tests and surgical management is the only means
for a diagnosis. Fertility sparing surgery may be acceptable when an
ovarian cystectomy can be performed and a frozen section is benign
in select cases. In cases which an ovarian cystectomy is decided upon
the surgeon must exercise caution to avoid cyst rupture as to not seed
the abdomen with potential malignancy if pathology demonstrates
a malignant process. Continued following of serum markers after
benign pathology is not usually necessary, but there should be some
consideration to following laboratory evaluation in patients with
ovarian cystectomy and ovarian preservation. The prognosis of
adnexal masses will depend on the pathological diagnosis and not the
elevation of inhibin.
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