Craig E. Barnes, MD; Ashley D. Hawkins, BA;
Michael Y. Chen, MD,
Department of Radiology, Wake Forest University School of
A healthy 2-month-old white infant boy was found by his
pediatrician to have a palpable pelvic mass at his well child
check. The patient had no clinical symptoms at the time. Laboratory
values were significant for an elevated urine homovanillic acid
(HVA)/creatinine ratio of 361, and a normal urine vanillylmandelic
acid (VMA)/creatinine ratio. Radiography (Figure 1),
ultrasonography (Figure 2), computed tomography (CT) (Figure 3),
and magnetic resonance (MR) imaging (Figure 4) were performed.
Radiography showed a pelvic soft-tissue fullness displacing the
bowel loops (Figure 1). No calcifications or bone changes were
noted. Ultrasonography confirmed the presence of a heterogeneous,
solid, presacral pelvic mass measuring 8.1 × 3.6 × 5.3 cm that
displaced the rectum and bladder anteriorly (Figure 2). The
contrast-enhanced CT scan showed a large central retroperitoneal
mass of the pelvis measuring 5.2 × 4.4 × 7.3 cm and extending from
the lower pelvis to the umbilicus (Figure 3). There was also
lateral displacement of the ureters and iliac arteries with
suggestion of soft-tissue extension around the lower sacrum and
coccyx. MR imaging of the lumbrosacral spine with (not shown) and
without (Figure 4) contrast showed an 8.6 × 4.2 × 4.6 cm
heterogeneously enhancing mass (Figure 4). The mass wrapped around
the coccyx and lower sacrum into the distal-most neuroforamina on
the right, which suggested a possible neural origin.
SURGICAL AND PATHOLOGICAL FINDINGS
During surgery, it was noted that the pelvic tumor had displaced
many internal organs. The colon was deviated toward the left, the
ureters were deviated laterally, and the rectum was shifted from
behind the bladder toward the left. The excised tumor measured 7.5
× 7.0 × 3.7 cm.
A bone-marrow biopsy and postoperative bone survey were both
negative. Histologic evaluation showed an undifferentiated, small
round, blue-cell tumor in a fibrillar background, a pattern
favoring neuroblastoma. Frozen-section pathology confirmed the
diagnosis of neuroblastoma.
Neuroblastoma, which most commonly occurs in children <2
years old, often presents with a large, fixed lobular mass that
extends from the flank toward the midline of the abdomen and
frequently surrounds retroperitoneal structures.
Eighty percent of all neuroblastomas arise in the abdomen and
thorax, with the most common site being the adrenal medulla. Only
5% of all primary neuroblastoma tumors arise in the pelvis.
Diagnosis and evaluation of childhood tumors usually include assays
for the urinary catecholamines HVA and VMA, as they are produced by
85% to 90% of neuroblastomas.
The role of imaging in childhood tumors includes confirming the
presence of a tumor, determining the site of origin of the tumor,
helping in tumor staging, and helping in treatment planning.
Radiographic differential diagnoses of presacral masses in children
include sacrococcygeal teratoma, anterior meningocele, neuroenteric
cyst, and lymphoma.
Sacrococcygeal teratomas are the most common childhood tumors seen
in the presacral region. Fat, calcification, and/or cystic changes
within a presacral mass would make this diagnosis more like-
In myelomeningocele and neurenteric cyst an accompanying sacral
defect is usually seen.
Lymphomas are not commonly presacral and most often are associated
with retroperitoneal and mesenteric lymphadenopathy.
Abdominal radiography showed a soft-tissue mass in the lower
pelvis, displacing the bowel superiorly. This is a nonspecific
sign. In our case, ultrasonography showed a heterogeneous, solid
well-demarcated presacral pelvic mass of mixed echogenicity. Areas
of increased echogenicity were thought to represent fatty
deposition or calcification. Doppler sonography showed prominent
vessels within the tumor along its posterior-inferior margin. On CT
scan, the neuroblastoma appeared as a presacral soft-tissue mass
with high attenuation within it, which represented calcifications.
MR imaging has been touted as a better way to evaluate cases of
suspected neuroblastoma because of its ability to delineate how the
tumor relates to local musculature and to assess the intraspinal
On the MR imaging study, the lack of fat or cystic change made a
presacral sacrococcygeal teratoma unlikely. The presence of a solid
mass with extension around the coccyx and into the distal-most
right neuroforamina was seen on MR imaging. This finding is
consistent with the diagnosis of neuroblastoma, which can have
intraspinal extension secondary to its neural origin.
We have reported an unusual case of neuroblastoma presenting as
a presacral mass in an otherwise healthy child. The lack of fat or
change makes sacrococcygeal teratoma a less likely diagnosis.
The presence of a solid mass in an infant having neuroforaminal
extension and calcification should prompt consideration of
neuroblastoma. This case of neuroblastoma stresses the importance
of searching for clues to the diagnosis, such as neuroforaminal
extension and calcification, as common diseases may present in