Primary Retroperitoneal Teratoma with Predominant Neurogenic Elements Masquerading as Adrenal Tumor
Sonam SHARMA , Leelavathi DAWSON, Ashish Kumar MANDAL
Department of Pathology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
Keywords: Retroperitoneal teratoma, Neurogenic elements, Adrenal neoplasm
Primary retroperitoneal teratomas are uncommon extragonadal nonseminomatous germ cell tumors that are composed of well differentiated
parenchymal tissues which are derived from more than one of the three embryonic germ cell layers. Here we report an unusual and first of its
kind, a case of primary mature cystic retroperitoneal teratoma mimicking as adrenal tumor in a 7-month-old female in which the tumor was
predominantly composed of neurogenic tissue histologically which is unlike the usual pattern seen in the teratomas.
Teratomas also known as dysembryoma, teratoblastoma,
organoid tumor and teratoid tumor, are encapsulated
neoplasms, that are the most common form of all germ cell
tumors (GCTs) and belong to nonseminomatous group
. They arise from abnormal development of
pluripotent cells: germ cells and embryonal cells, which in
turn greatly influences the age of presentation and involved
location. Teratomas of germ cell origin can be congenital
or acquired and are usually gonadal. In contrast, teratomas
of embryonic cell sources, which are always congenital
and are usually found in extragonadal (15%) locations,
such as sacrococcygeal , intracranial, cervical, mediastinal
. Major differences in their clinical
behavior suggest that gonadal and extragonadal tumors
are biologically different, though histological, serological,
and cytogenetic characteristics of all GCTs are similar3
The present case study describes a child with an atypical
presentation of a rare case of primary retroperitoneal
teratoma which posed a diagnostic challenge and is first of
its kind in terms of histology to be reported in the world
A 7-month-old female presented with a gradually
increasing lump in the left upper abdomen, which was
first noticed 3 months back. There was no history of fever,
weight loss, gastrointestinal, genito-urinary or respiratory
disturbances. Developmental milestones of the child were within normal range, with normal birth history. Her past
history and medical history were non-contributory.
On physical examination, a large intra-abdominal mass was
palpable in the left upper quadrant which was also extending
into the left epigastric and left lumbar region. It measured
around 9 x 8 cm and was firm, non-tender, moving with
respiration and dull on percussion. The overlying skin was
unremarkable. All other systemic examinations were within
normal limits. Routine haematological investigations were
unremarkable. Urine and blood cultures were negative.
Kidney, liver function tests, and X-ray of chest were normal.
Serum antibodies to human immunodeficiency virus and
hepatitis B surface antigen were negative.
Abdominal ultrasonography (USG) showed a large,
multicystic mass located between the spleen and left kidney.
There was no evidence of calcification in the tumor mass
or ascitis. Contrast enhancement computed tomography
(CECT) scan of abdomen and pelvis demonstrated a large
well circumscribed predominantly cystic retroperitoneal
mass occupying predominantly the left suprarenal region
(Figure 1A,B). It measured about 9.9 x 8.8 x 6.8 cm and
it showed multiple septae, a tiny fat and an enhancing
soft tissue attenuation area. No calcification was seen.
The mass displaced the aorta, celiac axis and superior
mesenteric vessels to the contralateral side and the left
kidney caudally with indentations to its contour. The left
renal vein was displaced antero-medially and draped along
the medial margin of the mass. The left adrenal gland could
not be detected separately from the mass. The body and tail of pancreas were displaced anteriorly while descending
colon and small bowel loops were displaced to right side.
There was no evidence of any significant abdominal and
pelvic lymphadenopathy or distant metastasis. Rest of the
abdominal and pelvic organs were unremarkable. Based on
these findings, a radiological suspicion of a cystic change
in a solid tumour originating from left adrenal gland (as
the normal left adrenal gland could not be recognized) or a
retroperitoneal cystic teratoma was made.
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|Figure 1: A,B) CECT abdomen
revealing a multicystic mass in the
a B retroperitoneum.
Laboratory investigations indicating a functioning adrenal
tumour, consisting of plasma and urinary levels of catecholamines,
rennin, aldosterone, cortisol, adrenocorticotrophic
hormone levels were within normal limits. Tumor
markers such as serum alpha-fetoprotein (AFP), lactate
dehydrogenase (LDH), neuron-specific enolase (NSE), carcino
embryonic antigen (CEA) and carbohydrate antigen
19-9 (CA 19-9), were also estimated. Serum values of AFP
(18.9 μg/dL ), CEA (6.6 ng/ml) , CA19-9 (50.2 U/ml) were
slightly higher whereas LDH and NSE were within normal
range , further ruling out the possibility of left adrenal
gland being the origin of this mass.
On exploratory laparotomy, a large well defined cystic
retroperitoneal mass occupying the left suprarenal area,
between the spleen and left kidney was seen. The left
adrenal gland was compressed and adhered to the tumor
mass. The mass abutted the left kidney and displaced it
inferiorly. The renal vessels were stretched and adherent
to the mass.The transverse and left colon were compressed
and displaced anteriorly whereas tail and body of the
pancreas were displaced posteriorly. No invasion into the
aorta or inferior vena cava was seen. No palpable regional
nodes were identified. The tumor mass was completely
excised and sent for histopathological examination.
Gross examination of the specimen received showed
a well-circumscribed cystic mass measuring 9.8 x 9 x
8 cm with an intact and smooth surface. On incision,
brownish fluid admixed with mucoid/jelly like material
came out and thin walled cyst was left. On cut section,
multiloculated cysts were seen along with a very small solid
grey yellow area measuring 0.8 x 0.8 x 0.5 cm (Figure 2A,B).
Histopathological examination of cyst wall and small solid
area showed predominantly mature neural tissue (Figure
3A). A glandular structure lined by ciliated columnar
epithelium (Figure 3B) with occasional foci of adipose
tissue and blood vessels could also be identified (Figure
4). Other mature or immature elements were not seen,
even on extensive sampling. On immunohistochemistry
(IHC), tumor cells were positive for synaptophysin and
glial fibrillary acidic protein. A final diagnosis of primary
retroperitoneal mature cystic teratoma with predominance
of neurogenic elements was made.
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|Figure 2: A) Gross specimen of retroperitoneal mass. B) Cut section revealing multilocular cystic component of the tumor.
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|Figure 3: A) Photomicrograph showing predominantly mature glial tissue (H&E; x200). B) Glandular
structure lined by ciliated columnar epithelium (H&E; x200) [Inset: Ciliated columnar epithelium (H&E; x400)]
The patient was discharged uneventfully in a stable
condition. Post operative 1 year follow up failed to reveal
any tumor recurrence.
Primary retroperitoneal neoplasms are a rare but diverse
group of benign and malignant tumors that arise within the
retroperitoneal space but outside the major organs in this
space. They can be solid or cystic masses, each of which can
be further subdivided into neoplastic and non-neoplastic
masses. Of the primary retroperitoneal neoplasms, 70%–
80% are malignant in nature, and these account for 0.1%–
0.2% of all malignancies in the body4
. Among them,
primary retroperitoneal teratomas are extremely unusual
neoplasms accounting for approximately 1–11% of all primary retroperitoneal neoplasms and typically occurs in
neonates, infants, and children5
Primary retroperitoneal teratomas involving adrenal
glands are exceedingly uncommon accounting for only
4% of all primary teratomas6 and can be mistaken for
adrenal neoplasms7. As in our case, based on radiology,
the left adrenal gland was inseparable from the mass, giving
an appearance that the tumor might have arisen from
the adrenal gland. Such an unusual radiological finding
may cause erroneous diagnosis. However, laboratory
investigations including serum tumor markers ruled out
the possibility of adrenal gland being the possible origin of
The diagnosis of this tumor is based on a combination of
high index of clinical suspicion, laboratory and radiological
investigations, though histopathology is the gold standard.
These tumors are usually asymptomatic but may manifest
as abdominal/back/flank pain, abdominal distention, or a
palpable abdominal mass, like in our case. Other symptoms
can be of genito-urinary or gastrointestinal tract, limb/
genital swelling and secondary infections. Rarely malignant
transformation and an acute syndrome can occur,
involving peritonitis, intestinal obstruction, or renal colic8. Laboratory investigations including serum tumor
markers played a pivotal role in our patient, in clinching
the diagnosis. The retroperitoneal teratomas have a
property of expressing various serum tumor markers such
as elevated AFP, CEA and CA 19-9. These markers can also
be used to monitor successful treatment or detect relapse in
patients with specific tumor marker-secreting teratomas as
suggested by few authors9.
Radiology has proved to be a valuable pre-operative
diagnostic tool but has its own limitations10,11. Plain
X-ray can demonstrate calcified material while USG can
differentiate between cystic and solid elements. CECT can
help to determine the size, extent of the tumor, relationship
to vessels and in differential diagnosis. Magnetic Resonance
Imaging (MRI) can offer better assessment of tumor staging
and distinction between benign and malignant neoplastic
features12. In our case, no calcification was seen both
on USG or CECT, and MRI was not done, owing to the
unaffordability by the patient.
Various differential diagnosis of retroperitoneal cystic
lesions are cysts (mesenteric, omental, splenic, enteric duplications,
mullerian, epidermoid, tailgut), solid neoplasms
with cystic change (paraganglioma, neurilemmomas, leiomyosarcomas),
mucinous/serous cystadenoma or cystadenocarcinoma,
haematoma, urinoma, lymphocoele, pancreatic and nonpancreatic
Complete surgical excision, either by open surgery or by
laparoscopy followed by histopathology evaluation is the
mainstay for its definitive diagnosis as well as treatment1,13. Usually teratomas, histopathologically consists of
multiple parenchymal tissues that are derived from more
than one germ cell layer6. Our case was interesting as
numerous sections were taken to locate the different
elements of teratoma microscopically, but we could only
find predominantly mature neurogenic element. However,
after extensive sampling, a glandular structure and a tiny
focus of adipose tissue could be identified. Therefore, this
case cannot be considered as pure monodermal. Thus, we
designated this case as primary mature cystic retroperitoneal
teratoma with predominance of neurogenic elements. An
extensive search of PubMed and Medline revealed one case with similar predominance of neurogenic elements
but that was in an ovarian mature cystic teratoma14.
The pathogenesis of these predominant specific tissues in
teratoma is still obscure. In our case, teratoma components
were mature but approximately 90% of the tumor area
showed glial tissue. Hence, the current case becomes a
relevant value addition to the existing world literature.
The prognosis of primary retroperitoneal teratomas is
generally good if the tumor is removed completely15. In
our case, the tumor was totally excised and the postoperative
as well as the follow up period was uneventful. Hence, it is
postulated that these tumors with predominant neurogenic
elements also behave in a benign manner as the primary
retroperitoneal mature teratomas do. However, a close
follow up is mandatory as recommended by few researchers
because of the possibility of its malignant transformation12,16.
In conclusion, primary retroperitoneal teratoma, though a
rare entity, should always be considered among differentials
of adrenal masses, as it can masquerade a primary adrenal
tumor, as seen in our case. Preoperatively laboratory and
radiological investigations do play an integral role, but it is
the histopathology which is confirmative. More insight is
required to understand the genesis and behaviour of these
tumors with one predominant element in teratomas.
CONFLICT of INTEREST
The authors declare no conflict of interest.
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