A 54-year-old man presented to our department with a 2-month history of back pain
and
painful urination. A contrast-enhanced computed tomography (CT) revealed a large retroperitoneal
soft tissue mass encircling the abdominal aorta, surrounding vessels, and the right
ureter
([Fig. 1]). He had an average leukocyte level (7300/µL), within the normal range for tumor
markers
and IgG4 levels, and a C-reactive protein level of 38.88 mg/L. The clinical picture
was highly
suggestive of retroperitoneal fibrosis (RPF); however, for a definite diagnosis, a
biopsy of the
lesion was necessary.
Fig. 1 Contrast-enhanced computed tomography showed an abnormal retroperitoneal soft tissue
mass encircling the abdominal aorta.
CT-guided aspiration biopsy was not an option as the blood vessels and bowel could
not be avoided. Therefore, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB)
was selected as the optimal method for obtaining tissue samples, as it is a minimally
invasive technique that has previously demonstrated efficacy.
We decided to perform transcolonic EUS-FNB because of the lesion’s proximity to the
pelvis ([Video 1]). In addition to avoiding adjacent blood vessels, transcolonic EUS-FNB allows for
a comprehensive view of the lesion from all sides. Therefore, we proceeded with an
ultrasound endoscope (EG-3870UTK; Pentax, Tokyo, Japan) to the ileocecal region and
then withdrew the endoscope to observe and select the optimal puncture position when
the lesion was visible.
Transcolonic endoscopic ultrasound-guided fine-needle biopsy of retroperitoneal fibrosis.Video
1
EUS disclosed a diffuse echo-reduced mass surrounding the distal aorta ([Fig. 2]), and Doppler imaging confirmed the absence of interpolated vessels. Subsequently,
two locations in the ascending colon were selected for lesion puncture using a 22-gauge
ultrasound biopsy needle (Cook EchoTip Procore HD Endobronchial Ultrasound Biopsy,
G34281; Cook Medical, Bloomington, Indiana, USA). Biopsy results confirmed a definite
histopathologic diagnosis of RPF ([Fig. 3]), and immunohistochemical analysis indicated CD38 and Congo red staining positivity.
The patient did not experience any severe adverse events, and he was successfully
treated with prednisolone and azathioprine.
Fig. 2 Transcolonic endoscopic ultrasound revealed a retroperitoneal, diffuse echo-reduced
mass suggestive of retroperitoneal fibrosis.
Fig. 3 Histopathologic image of the specimen obtained from endoscopic ultrasound-guided fine-needle
biopsy, showing fibrous tissue in cells, together with lymphocytes between the connective
tissue fibers.
EUS-FNB can become a safe and effective diagnostic method for RPF [1]. Transduodenal EUS-FNB is unable to penetrate lesions in close proximity to the
pelvic cavity. Conversely, transcolonic EUS-FNB can be utilized to identify and select
multiple potential puncture sites while avoiding the vicinity of blood vessels, thereby
ensuring a safe and precise procedure. Therefore, in cases of RPF affecting the lower
abdomen or the region in proximity to the pelvis, a transcolonic EUS-FNB may be a
viable option for diagnosis.
Endoscopy_UCTN_Code_TTT_1AS_2AZ
E-Videos is an open access online section of the journal Endoscopy, reporting on interesting cases and new techniques in gastroenterological endoscopy.
All papers include a high-quality video and are published with a Creative Commons
CC-BY license. Endoscopy E-Videos qualify for HINARI discounts and waivers and eligibility is automatically checked during the submission
process. We grant 100% waivers to articles whose corresponding authors are based in
Group A countries and 50% waivers to those who are based in Group B countries as classified
by Research4Life (see: https://www.research4life.org/access/eligibility/).
This section has its own submission website at https://mc.manuscriptcentral.com/e-videos.
