Retroperitoneal lymphadenopathy often causes suspicion of lymphoma or gastrointestinal
malignancy, especially when primary lesions are not apparent. However, testicular
seminoma may initially present as retroperitoneal lymph node metastasis [1 ]
[2 ]. We report a case of retroperitoneal seminoma in a patient without an overt testicular
mass that required endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA;
EUS-FNA) for an accurate diagnosis.
A 53-year-old man was referred to our hospital because of retroperitoneal lymphadenopathy.
Neither upper nor lower gastrointestinal endoscopy revealed any abnormalities, and
contrast-enhanced computed tomography (CT) did not reveal a clear primary tumor. However,
para-aortic lymph node swelling was observed. Therefore, malignant lymphoma was initially
suspected. EUS revealed a homogeneous 30-mm lymph node adjacent to the aorta, and
EUS-FNA was performed using a 22-G needle. Unlike typical lymphomas, the lesion was
firm during puncture ([Fig. 1 ]).
Fig. 1 Imaging and endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA; EUS-FNA)
of retroperitoneal lymphadenopathy. a Contrast-enhanced computed tomography (CT) showed para-aortic lymph node enlargement.
b EUS revealed a homogeneous 30-mm lymph node adjacent to the aorta. c EUS-FNA was performed using a 22-G needle. Unlike typical lymphomas, the lesion and
node felt firm.
Histopathology demonstrated tumor cells positive for c-KIT, SALL4, and Oct-3/4 as
well as those negative for AFP and CD30, consistent with seminoma. Subsequent focused
CT revealed a 14-mm nodular lesion in the right testis. High inguinal orchiectomy
confirmed an 11-mm pure seminoma [2 ] ([Fig. 2 ], [Video 1 ]).
Retroperitoneal lymph node metastasis as the initial presentation of testicular seminoma
diagnosed using endoscopic ultrasound-guided fine-needle aspiration.Video 1
Fig. 2 Imaging of the primary seminoma and metastatic pattern. a T1-weighted magnetic resonance imaging (coronal view) showed right testicular enlargement
with a mosaic pattern. b Contrast-enhanced CT revealed a mildly hyperdense nodular lesion in the right testis.
c CT showed lymphatic spread from the testis via the spermatic cord to the para-aortic
lymph node.
This case highlights several important points. First, retroperitoneal lymphadenopathy
requires a broad differential diagnosis, including lymphoma, gastrointestinal tumors,
and urogenital malignancies. Second, with seminoma, metastatic lymphadenopathy can
precede the identification of the primary lesion, particularly when the testicular
tumor is small or regressed [1 ]
[3 ]. Third, lymphatic drainage from the testis follows the spermatic cord and reaches
the retroperitoneal nodes near the renal hilum, thus explaining the observed distribution.
Finally, seminoma should be considered in the differential diagnosis of retroperitoneal
lymphadenopathy in young and middle-aged men. A systematic diagnostic strategy that
includes EUS-FNA and dedicated testicular imaging is crucial [3 ]. EUS-FNA plays a pivotal role in diagnosing such cases, especially when the primary
lesion is inconspicuous.
Endoscopy_UCTN_Code_CCL_1AF_2AZ_3AD
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