Testicular Microlithiasis in the Setting of Primary Extragonadal Germ Cell Tumor

1. Testicular Microlithiasis in the Setting of Primary
Extragonadal Germ Cell Tumor
A Case Series
Joel P. Thompson, MD, MPH,* Jerome Jean-Gilles, Jr, MD,† and Vikram Dogra, MBBS*
Abstract: The clinical significance of testicular microlithiasis (TM)
in patients with primary extragonadal germ cell tumor (EGCT) is
not well understood. When EGCT is suspected, sonographic and
physical examination of the testicles should be performed to evaluate
for testicular lesion or atrophy; negative testicular ultrasound with
current technology virtually excludes the possibility of occult pri-
mary lesion. Although EGCTs are known to be associated with ele-
vated level of serum tumor markers, the utility of tumor markers in
the presence of TM is not well understood. Current guidelines for
TM follow-up and management do not include any potential correla-
tion between TM and primary EGCT, an association that should be
addressed on future updates.
Key Words: testicular microlithiasis, extragonadal germ cell tumor,
testicular ultrasound
(Ultrasound Quarterly 2017;33: 41–45)
Primary extragonadal germ cell tumors (EGCTs) comprise
only 1% to 4% of all germ cell tumors and by definition
occur outside the gonads, most commonly in the anterior me-
diastinum and retroperitoneum.1,2
Testicular microlithiasis
(TM) was once thought to be strongly associated with the de-
velopment of testicular cancer but now is thought to have a
very low risk of concurrent or development of testicular germ
cell tumor in the absence of other risk factors.3,4
Here, we re-
port 2 cases of TM in the setting of primary EGCTs.
CASE 1
A 49-year-old man presented with complaint of left lower
lumbar pain for 2 months, with more recent development of in-
termittent low-grade fever and night sweats. Computed to-
mography (CT) imaging revealed a large left retroperitoneal
mass with bilateral retrocrural lymphadenopathy (Fig. 1).
Computed tomography–guided percutaneous core biopsy of
the left para-aortic mass was nondiagnostic. Subsequent diag-
nostic laparoscopy with biopsy of the left retroperitoneal mass
demonstrated histologic findings consistent with seminoma of
primary origin (Fig. 1). Tumor cells were positive for OCT 3/4
and c-Kit.
The patient had normal serum α-fetoprotein (AFP) and
β-human chorionic gonadotropin (β-hCG) levels, and mildly
elevated serum lactate dehydrogenase (LDH) level (349 U/L;
reference range, 118–225 U/L). Scrotal ultrasound (Fig. 1) re-
vealed classic TM (5 or more microliths per field of view) and
no focal lesion or macrocalcifications. Testicular volumes
were calculated using a spheroid calculation (length  width Â
height  0.52), revealing bilateral testicular atrophy (right tes-
ticular volume, 3.5 cm3
; left, 4.3 cm3
; reference, >12 cm3
).3
Im-
aging did not reveal any additional sites of metastatic disease.
The patient was diagnosed with primary extragonadal retro-
peritoneal seminomatous germ cell tumor, stage IIC (pTxN3Mx).
He underwent systemic cisplatin-based chemotherapy: 3 cycles
of platinum-based chemotherapy. The primary tumor and retro-
peritoneal lymphadenopathy regressed, and he is tumor free for
more than 2.5 years after completing chemotherapy.
CASE 2
A 57-year-old man with history of alcohol abuse and re-
mote hepatitis C infection presented with chest pain. Further
history revealed recent 30- to 40-lb weight loss and increasing
fatigue. A chest radiograph revealed a prominent right upper
hilum. Subsequent chest CT demonstrated a 4 Â 3.5-cm right
hilar mass (Fig. 2). Endobronchial fine-needle aspiration was
performed, with histology results consistent with primary
seminoma (Fig. 2), positive for OCT 3/4 and c-Kit and nega-
tive for PLAP, LCA, pan-cytokeratin, S-100, CD3, TTF-1, and
CDX-2. The patient's serum AFP, β-hCG, and LDH levels were
within normal limits.
Scrotal ultrasound demonstrated bilateral classic TM,
normal testicular volume, and no abnormal lesions (Fig. 2).
Staging positron emission tomography/CT 1 week later dem-
onstrated the hypermetabolic right hilar mass (standardized
uptake value, 6) and low-grade uptake in a subcarinal node
(which was negative for malignancy on endobronchial bi-
opsy) (Fig. 2). He underwent platinum-based chemotherapy.
The right hilar mass decreased in size; he is tumor free for
more than 2 years after completing chemotherapy.
DISCUSSION
Testicular microlithiasis results from laminated calcium
deposition within the seminiferous tubules or calcification along
the tubular basement membrane.5–7
Testicular microcalcifications
Received for publication April 15, 2016; accepted June 3, 2016.
*Department of Imaging Sciences and †Department of Pathology and Labora-
tory Medicine, University of Rochester Medical Center School of Medi-
cine and Dentistry, Rochester, NY.
The authors declare no conflict of interest.
Address correspondence to: Vikram Dogra, MBBS, University of Rochester
Medical Center, 601 Elmwood Ave, Box 648 Rochester, NY 14642
(e‐mail: vikram_dogra@urmc.rochester.edu).
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
DOI: 10.1097/RUQ.0000000000000251
Ultrasound Quarterly • Volume 33, Number 1, March 2017 www.ultrasound-quarterly.com 41
CORRESPONDENCE
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.

2. are less than 3 mm in size without posterior shadowing and are
too small for visualization on CT or magnetic resonance im-
aging; therefore, TM diagnosis is usually made using high-
frequency ultrasound transducers. Testicular microlithiasis
prevalence estimates range from 0.6% to 9%.8
A broad definition of TM is 5 or more microliths within
the testicle. However, a more stringent definition of 5 or more
microliths per field of view is preferred to better capture the
idea of clustering.3,8
Clustering of calcifications may identify
unstable regions of intratubular germ cell neoplasia within the
testis or represent sequela of burned-out testicular tumors.9
Up to 50% of intratubular germ cell neoplasias may progress
into malignancy within 5 years.3,10
Testicular microlithiasis
is a separate entity from coarse or macrocalcifications, which
may be associated with active or burned-out testicular tumors.11
Testicular microlithiasis was once thought to be strongly
associated with the development of testicular cancer. More re-
cent analysis suggests that TM in otherwise healthy, asymptom-
atic individuals has a very low absolute risk of concurrent or
development of testicular germ cell tumor or intratubular germ
cell neoplasia. However, in patients referred because of symp-
toms or risk factors, TM was associated with a risk ratio of
8.5 (confidence interval, 4.5–16.1) for concurrent testicular germ
cell tumor and risk ratio of 10.5 (confidence interval, 5.3–20.8)
for intratubular germ cell neoplasia.10
The most recent guide-
lines place emphasis on testicular cancer risk factors rather than
the presence of TM to guide patient follow-up and management.
Risk factors include prior history or first-degree family history
of germ cell tumor, history of cryptorchidism or orchidopexy,
testicular atrophy (volume, <12 mL), infertility, and genetic dis-
eases such as Klinefelter syndome.3,4
Extragonadal germ cell tumors most commonly occur in
the mediastinum, followed by the retroperitoneum; by defini-
tion, they occur without an identifiable gonadal primary lesion.
Additional common sites include the midline retroperitoneum
or intracranially in the pineal or suprasellar regions.1,2
Ma-
ture teratomas comprise 60% to 70% of EGCTs, followed by
seminomas.2
Mean age of discovery of EGCTs in adults is
47 years, which is later than the average age of presentation of
testicular germ cell tumors.12
The origin of primary retroperitoneal EGCTs is debated.
One hypothesis is that they arise from primordial germ cell
rests along the midline of the body (urogenital tract) that fail
to migrate to the genital ridges.2,13
A second hypothesis is that
germ cells from the testes undergo reverse migration, particu-
larly because EGCTs exhibit similar chromosomal abnormal-
ities to gonadal germ cell tumors.14–16
Multiple studies also
suggest that suspected retroperitoneal EGCTs are actually of
metastatic origin from clinically occult testicular tumors.1,9
Testicular germ cell tumors follow a predictable pattern of
lymphatic spread to ipsilateral retroperitoneal nodes at the
level of the renal vessels. When retroperitoneal EGCT is iden-
tified, thorough investigation for a testicular primary should
be performed. The identification of a testicular primary lesion
FIGURE 1. A 49-year-old man with primary retroperitoneal seminoma and TM. A, Coronal contrast-enhanced CT demonstrating
partially necrotic left retroperitoneal masses. B, Histological specimen with hematoxylin and eosin stain demonstrates cohesive
epitheloid cells with clear cytoplasm and round nuclei with prominent nucleoli (arrowhead), along with fibrous band with
lymphcytes (arrow). C and D, Testicular ultrasound demonstrating bilateral TM and atrophy, but no focal lesion.
Thompson et al Ultrasound Quarterly • Volume 33, Number 1, March 2017
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Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.

3. has important treatment implications, because the blood-testis
barrier may harbor the malignancy in up to 50% of patients
despite systemic chemotherapy.1,17,18
The association between primary EGCT and TM is not
well understood. We identified 9 case reports of TM in the
setting of primary EGCT (Table 1).17,19–26
Of the 10 previ-
ously reported patients, 6 are 22 years or younger, with most
of the primary lesions occurring in the anterior mediastinum.
We are not aware of any case reports of TM in the setting of
primary intracranial EGCT.
Meyer et al17
reported TM in a 16-year-old with extra-
gonadal yolk sac tumor, which stimulated debate as to the sig-
nificance of TM.27,28
The authors suggested that TM may
represent burned-out intratesticular tumor.17
However, subse-
quent letters to the editor positioned that burned-out tumors
are most often associated with coarse macrocalcifications;
therefore, TM was thought to indicate synchronous presence
of intratubular germ cell neoplasia.27
However, the potential association between TM and
EGCT in prior case reports is not well understood. It is possi-
ble that testicular carcinoma in situ did not develop into an in-
vasive lesion, but some tumor cells gave rise to metastasis,
as suggested by Scholz et al.1
However, because testicular tu-
mors generally have a predictable pattern of lymphangitic
spread to ipsilateral retroperitoneal lymph nodes at the level
of the renal vessels, metastatic disease does not explain the
presence of anterior mediastinal EGCT in the absence of ret-
roperitoneal lymphadenopathy (such as patient 2 in this case
series). However, it is possible that TM indicates the presence
of intratubular germ cell neoplasia that is incidental to the
presence of primary EGCT.
On the basis of case reports to date, most patients with
primary EGCT and TM have elevated levels of serum tumor
markers (Table 1). Elevated serum β-hCG and LDH levels
may occur with any germ cell tumor histology. α-Fetoprotein
is produced by endodermal sinus tumor components and is
FIGURE 2. A 57-year-old man with primary right hilar seminoma and TM. A, Noncontrast chest CT reveals a right hilar soft tissue
mass, biopsy-proven seminoma. B, Positron emission tomography image demonstrates fludeoxyglucose-avid right hilar mass
without evidence of additional hypermetabolic foci. C, Histological specimen with hematoxylin and eosin stain shows cohesive
epitheloid cells with clear cytoplasm and round nuclei with prominent nucleoli (arrow), along with cartilaginous tissue (arrowhead).
D, Transverse view through both testicles demonstrates TM. No focal lesion was present.
Ultrasound Quarterly • Volume 33, Number 1, March 2017 Testicular Microlithiasis and Extragonadal GCTs
© 2017 Wolters Kluwer Health, Inc. All rights reserved. www.ultrasound-quarterly.com 43
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.

4. therefore not elevated in pure seminomas.29
Elevated LDH
level is reported to be the result of aberrant methylation of
the LDHA gene promoter in cancer cells; however, elevated se-
rum LDH level is nonspecific and may occur in a large number
of both benign and malignant conditions.29,30
The American
Society of Clinical Oncology recommends against the use of
measuring serum tumor markers in screening the general pop-
ulation for germ cell tumors but does advocate for measure-
ment before surgery and chemotherapy to risk stratify patients
and to screen for disease recurrence. In case reports of patients
with primary EGCT and TM, half presented with elevated se-
rum LDH level. To our knowledge, the utility of measuring se-
rum LDH in patients with TM has not been directly studied.
Although only several patients have been reported to have an
elevated β-hCG level, 1 prior case report postulated an associ-
ation between TM and elevated serum β-HCG level.21
One limitation of this case series is that testicular bi-
opsies were not performed to exclude occult testicular tumors.
In 1 case series of 26 patients with suspected primary retro-
peritoneal EGCT, 25 patients had viable tumor or evidence
of burned-out testicular tumor.1
However, although all 20 of
those patients were reported to have lesions and/or micro-
calcifications on sonographic examination, it is not known if
these patients had bilateral TM or focal clustering of calcifica-
tions. High-frequency ultrasound has been shown to have a
sensitivity of nearly 100% for identifying scrotal pathology.
In a series of 284 patients observed for 3 years, there were no
false-negative scrotal ultrasound examinations.31
A subsequent
series of 411 patients also reported no false-negative scrotal ul-
trasounds when assessing for testicular pathology.32
Therefore,
in the setting of suspected primary EGCT, normal scrotal ultra-
sound virtually excludes the presence of testicular primary le-
sion. Furthermore, several case reports of TM in the setting of
EGCT included needle or surgical testicular biopsy to exclude
a subclinical tumor, and no ultrasound-occult primary testicular
malignancies were identified.21,22,24
It is possible that the co-occurrence of TM and EGCT
in these patients is random coincidence. We are not aware
of any study assessing a relationship between these entities
in the same population; comparing between studies is also dif-
ficult because of differences in study populations. Within these
limitations, we sought to calculate the probability of both TM
and EGCT occurring in the same individual. The incidence of
EGCT in males age 15 to 55 years is 1.5 cases per million per
year.33
A published prevalence estimate of TM in a meta-
analysis is 1.92%, which is used for the base case calculation
(published prevalence range of 0.6% to 9%).34
The intersec-
tion of these entities, assuming independence, is 0.03 cases
per million (range of 0.01 to 0.14 cases per million depending
on the prevalence of TM). Therefore, it is exceedingly rare for
EGCT to arise in the setting of TM in the absence of any cor-
relative or causative relationship.
The clinical significance of TM in patients with primary
EGCT is not well understood. Full sonographic and physical
examination of the testicles should be performed to evaluate
for testicular lesion or atrophy. Negative sonographic evalua-
tion of the testicles with current technology virtually excludes
the possibility of occult primary testicular lesion. Although
EGCTs are known to be associated with elevated level of se-
rum tumor markers, the utility of tumor markers in the pres-
ence of TM is not well understood. Current guidelines for
TM follow-up and management do not address any potential
correlation between TM and primary EGCT,3
an association
that should be further investigated on future updates.
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TABLE 1. Case Reports of Primary EGCT in the Setting of TM
Year Author
Patient
Age, y Symptom Location Histology
Elevated Levels of
Tumor Markers
1997 Aizenstein et al19
18 None (patient with
Klinefelter syndrome)
Mediastinum Mature teratoma Unknown
1998 Howard et al20
15 Chest pain Anterior mediastinum Immature teratoma AFP, β-HCG, LDH
1998 Nishiyama et al21
19 Chest pain Anterior mediastinum Choriocarcinoma β-HCG
1999 Matsumoto et al22
43 Palpable mass Left supraclavicular mass Seminoma —
2000 Quane and Kidney23
22 Dyspnea, fatigue, weight loss Anterior mediastinum Nonseminomatous mixed GCT AFP
2002 Sato et al24
19 Cough Anterior mediastinum Seminoma β-HCG, LDH
2010 Meyer and Gilbertson-Dahdal17
16 Abdominal pain, emesis Retroperitoneal Yolk sac tumor AFP, LDH
2010 Telles et al25
27 Hemoptysis Anterior mediastinum Seminoma β-HCG
2013 Barchetti et al26
33 Abdominal pain, weight
loss, jaundice
Retroperitoneal Yolk sac tumor* LDH
39 Back pain Retroperitoneal Immature teratoma LDH
2016 Our cases 49 Back pain Retroperitoneal Seminoma LDH
57 Chest pain Right hilar Seminoma —
*Yolk sac tumor is also known as endodermal sinus tumor.
Thompson et al Ultrasound Quarterly • Volume 33, Number 1, March 2017
44 www.ultrasound-quarterly.com © 2017 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.

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