Available via license: CC BY
Content may be subject to copyright.
66 Radiol Bras. 2018 Jan/Fev;51(1):58–68
Letters to the Editor
Dear Editor,
A 40-year-old female patient presented with diffuse abdomi-
nal pain after cholecystectomy with biliary tract exploration for
choledocholithiasis and underwent computed tomography (CT)
of the abdomen for better evaluation. The patient presented with
no other comorbidities and was not taking any medications. The
CT of the abdomen was performed with water-soluble iodinated
contrast medium and three-dimensional (3D) reconstruction
(Figures 1A, 1C, and 1D). In addition to liquid collections sug-
gestive of biloma, CT revealed a distinct, encapsulated reniform
parenchymal mass, anteriorly and near the lower pole of the
right kidney, with a rotational anomaly. Subsequent magnetic
resonance imaging of the urinary tract also demonstrated pelvic
communication between the ipsilateral renal masses and a single
ureter (Figure 1B).
Congenital anomalies of the urinary tract have been the ob-
ject of recent studies in the radiology literature of Brazil(1–3). A
supernumerary kidney is a rare congenital anomaly of the urinary
Supernumerary kidney with pelvic communication and a single ureter tract, fewer than 100 cases having been documented in the lit-
erature, with no difference between the genders and preferential
occurrence on the left side. Because of its rarity, it typically goes
undiagnosed until the fourth decade of life(4,5). A supernumerary
kidney has its own capsule, as well as its own blood supply, and
can be totally separate from the ipsilateral kidney or attached to
it by brous tissue or a parenchymal bridge. In general, the sum
of the volume of ipsilateral fragments is equal to or greater than
that of a normal kidney. The blood vessels that supply the super-
numerary kidney typically originate from the aorta, and drainage
is via the inferior vena cava(6,7).
The embryological basis for the occurrence of a supernu-
merary kidney has not been fully elucidated. One of the main
theories is that there is complete duplication of the ureteral bud,
with independent penetration into the metanephric blastema,
which develops and divides into two kidneys. Another theory is
that there are two independent ureteral buds that penetrate the
metanephric blastema, which then divides(7). It is believed that a
supernumerary kidney with a ureter that has its own insertion site
in the bladder reects an initial division of the mesenchyma be-
Figure 1. A: 3D reconstruction of a CT scan
of the abdomen (excretory phase) showing
a normal left kidney and a supernumerary
kidney in a caudal position and anterior to
the right kidney, with pelvic communication
between them. B: T2-weighted fat-saturated
enhanced fast gradient-recalled echo mag-
netic resonance imaging sequence (excre-
tory phase), with 3D coronal reconstruction,
showing pelvic communication between the
normal right kidney and the supernumerary
kidney, with a single ureter. C,D: Coronal and
sagittal reconstructions of a CT scan of the
abdomen (excretory phase), showing a nor-
mal left kidney, and a distinct and encapsu-
lated reniform parenchymal mass, caudal
and anterior to the right kidney, consistent
with a supernumerary kidney, connected by
a parenchymal bridge with pelvic communi-
cation between the two.
A B
C D
67
Radiol Bras. 2018 Jan/Fev;51(1):58–68
Letters to the Editor
http://dx.doi.org/10.1590/0100-3984.2016.0094
Renata Mendes da Silva1, Jorge Chaib Neto2, Moaci Ferreira
de Morais Júnior2
1. Hospital Universitário da Universidade Federal do Piauí (HU-UFPI), Teresina,
PI, Brazil. 2. Universidade Federal do Piauí (UFPI), Teresina, PI, Brazil. Mailing
address: Dra. Renata Mendes da Silva. Hospital Universitário da Universidade
Federal do Piauí – Radiologia. Campus Universitário Ministro Petrônio Portela,
SG 07, s/n, Ininga. Teresina, PI, Brazil, 64049-550. E-mail: renatamendesa20@
hotmail.com.
fore insertion and branching of the ureteral bud. A supernumer-
ary kidney with a ureter that fuses with that of the normal kidney
probably reects late division of the metanephric mesenchyma(7).
A supernumerary kidney can present as a palpable abdomi-
nal mass, with or without symptomatic nephrolithiasis, hydrone-
phrosis, upper urinary tract infection, or renal tumors. However,
it is typically asymptomatic and does not affect renal function.
Therefore, they are never diagnosed or discovered incidentally(5).
REFERENCES
1. Shigueoka DC. Anatomic variations of the renal arteries, as characterized
by computed tomography angiography: rule or exception? Its usefulness
in surgical plannning. Radiol Bras. 2016;49(4):vii–viii.
2. Mello Júnior CF, Araujo Neto SA, Carvalho Junior AM, et al. Multide-
tector computed tomography angiography of the renal arteries: normal
anatomy and its variations. Radiol Bras. 2016;49:190–5.
3. Silva RM, Morais Júnior MF, Mont’Alverne Filho FE. Pancake kidney
with cysts and a single ureter. Radiol Bras. 2016;49:127–8.
4. Sureka B, Mittal MK, Mittal A, et al. Supernumerary kidneys – a rare
anatomic variant. Surg Radiol Anat. 2014;36:199–202.
5. Suresh J, Gnanasekaran N, Dev B. Fused supernumerary kidney. Radiol
Case Reports. 2011;6:552.
6. Maranhão CP, Miranda CM, Santos CJ, et al. Congenital upper uri-
nary tract abnormalities: new images of the same diseases. Radiol Bras.
2013;46:43–50.
7. Favorito LA, Morais AR. Evaluation of supernumerary kidney with fusion
using magnetic resonance image. Int Braz J Urol. 2012;38:428–9.
Cricoid and cervical osteophytes causing dysphagia: an extremely
rare and interesting case
Dear Editor,
A 54-year-old male presented to our department with a two-
month history of nonprogressive dysphagia to solids and irrita-
tion in the neck. Physical examination and laboratory ndings
were unremarkable. Soft tissue X-ray of the neck, in lateral view,
revealed anterior bridging osteophytes at the C5-C6 level and
an elongated osteophyte in the region of the cricoid cartilage
(Figure 1A). An axial computed tomography (CT) scan showed
the formation of a spur, 2 mm in diameter, extending from the
cricoid cartilage (Figure 1C). Sagittal reconstruction revealed a
cricoid osteophyte extending 9 mm caudally at the C5-C6 level
(Figure 1D). Barium swallow revealed smooth extrinsic indenta-
tion in the esophagus at the level of osteophytes (Figure 1B). The
difculty in swallowing was attributed to the compression of the
esophagus by the cricoid and cervical osteophytes.
Figure 1. A: Soft tissue X-ray of the neck,
in lateral view, showing large anterior os-
teophytes (white arrow) of the C5 and C6
vertebral bodies and an elongated cricoid
osteophyte (black arrow). B: Barium swal-
low revealing a smooth extrinsic indenta-
tion in the esophagus at the level of the
osteophyte formation (arrow). C: Axial CT
scan showing an osteophyte arising from
the cricoid cartilage (arrow). D: Sagittal
reconstructed CT images showing an elon-
gated cricoid osteophyte caudally (arrow)
at the C5-C6 level.
°
°
A B
C D
±
°