We have recently published our pilot data on endoscopic
ultrasonography (EUS) for staging prostate cancer [1].
EUS with flexible instruments has the additional potential for imaging the
iliac region in the search for lymph node metastases with confirmation by
EUS-guided fine-needle aspiration (FNA) in prostate cancer; this is an area
that cannot be accessed with nonoptical transrectal rigid ultrasonography
(TRUS) probes.
A 65-year-old man was referred with an increased prostate-specific
antigen (PSA) level of 37.9 ng/mL. An abdominopelvic CT scan was normal.
Transrectal EUS was performed to image the prostate and revealed a hypoechoic,
round nodule in the peripheral zone of the prostate ([Fig. 1]). Multiple EUS-guided FNA passes were done
using a 22-gauge needle (Wilson-Cook, Winston–Salem, North Carolina,
USA). Cytopathological study showed undifferentiated adenocarcinoma. An
enlarged iliac lymph node (13 mm) was seen by EUS by advancing the
echoendoscope to the level of the iliac vessels (around
20 – 25 cm from the anus). Transcolonic EUS-FNA of
the left iliac lymph node was done in the same exam ([Figs. 2] – [4]), and histopathology demonstrated metastatic
undifferentiated prostate adenocarcinoma ([Fig. 5]).
Fig. 1 Transrectal endoscopic
ultrasonography (EUS) of the prostate, revealing a hypoechoic, round, and
homogeneous nodule in the peripheral zone of the prostate (*).
Fig. 2 An enlarged iliac lymph
node (ln). iv, Iliac vein; ia, iliac artery.
Fig. 3 EUS-guided fine-needle
aspiration (EUS-FNA) of the iliac lymph node with the needle in the center of
the lymph node.
Fig. 4 EUS-FNA of the iliac
lymph node with the needle tip at the periphery of the lymph node.
Fig. 5 Cytopathological section
from EUS-FNA of the iliac lymph node, showing a metastatic adenocarcinoma with
cytology similar to that of the prostate FNA.
Staging techniques for prostate cancer include ultrasonography, CT,
and magnetic resonance imaging (MRI). Ultrasonography, by the transabdominal,
transurethral, transperineal, or transrectal route, allows characterization of
the prostate parenchyma. Other techniques for local and nodal staging of
prostate cancer include MRI, magnetic resonance spectroscopic imaging (MRSI),
dynamic-enhanced MRI, positron emission tomography (PET), endorectal power
Doppler ultrasonography, lymphotropic MRI contrast agents, and diffusion MRI
[2]
[3]. EUS may be another useful
method for high-resolution imaging of prostate cancer [1]. Lymph node staging is an important issue in prostate
cancer that directly impacts management and outcome. Digital rectal examination
and TRUS are not accurate in predicting lymph node metastases
[4]. A meta-analysis by Hovels et al. [5] showed a low accuracy of CT and MRI for lymph node
staging of prostate cancer. We believe that there is potential for EUS with FNA
to play an important, minimally invasive role in lymph node staging of prostate
cancer.
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