|
IMAGING
MRI
in the histologic characterization of testicular neoplasms
Tsili AC, Tsampoulas C, Giannakopoulos X, Stefanou D, Alamanos Y, Sofikitis
N, Efremidis SC
Department of Clinical Radiology, University Hospital of Ionnina, Ioannina,
Greece
AJR Am J Roentgenol. 2007; 189: 331-7
- Objective:
The purpose of our study was to investigate the potential role of MRI
in the preoperative characterization of the histologic type of testicular
tumors and, more specifically, to differentiate seminomatous from nonseminomatous
testicular neoplasms.
- Materials
and Methods:
Twenty-one patients with histologically proven germ cell testicular
tumors underwent MRI of the scrotum on a 1.5-T unit. T2- and T1-weighted
sequences before and after i.v. administration of gadolinium chelate
were performed. MRI studies were retrospectively reviewed by two radiologists
and findings were correlated with the histopathologic diagnosis. An
attempt was made to differentiate seminomatous from nonseminomatous
testicular tumors on the basis of signal intensity and homogeneity of
the lesions, presence of fibrovascular septa, tumor encapsulation, and
patterns of contrast enhancement. Interobserver agreement was assessed
using weighted kappa statistics.
-
Results:
MRI findings correctly characterized 19 (91%) of 21 testicular neoplasms
(nine seminomatous and 10 nonseminomatous testicular tumors), with excellent
interobserver agreement. The presence of an intratesticular lesion of
predominantly low signal intensity on T2-weighted images, with septa
enhancing more than tumor tissue after contrast material administration,
was more suggestive for the diagnosis of a seminoma. Tumors that were
markedly heterogeneous both on unenhanced and contrast-enhanced images
were indicative of a nonseminomatous neoplasm.
- Conclusion:
Our study shows that MRI provides a credible preoperative differentiation
of seminomatous from nonseminomatous testicular tumors, with excellent
interobserver agreement.
- Editorial
Comment
Imaging plays an important role in the evaluation of testicular masses.
Ultrasound is still the first imaging modality to be used since adds
essential information in distinguish intratesticular from extratesticular
lesions. US is also useful for adequate characterization of the vast
majority of benign intra-scrotal lesions. The combination of clinical
findings and sonography is usually sufficient for adequate management
of the most scrotal masses since sonography is nearly 100% sensitive
for detection of testicular tumors. On sonography, seminoma appears
usually as a homogeneous hypoechoic lesion. The entire testis is replaced
by tumor in more than half the cases and small cystic areas can be found
in about 10% of tumors. Non-seminomatous tumors often have an inhomogeneous
echotexture, irregular or ill-defined margins, echogenic foci (hemorrhage
or calcification) and cystic necrosis. Both tumors present increased
flow on color Doppler US. Sometimes some benign intratesticular lesions
resemble malignant tumor on US. The authors of this manuscript confirm
previous reports that MRI is an excellent technique for adequate differentiation
of seminomatous from non-seminomatous testicular tumors (1). Although
this information is essential for determining adequate treatment and
prognosis an attempt to pre-operatively differentiate seminomatous from
non-seminomatous testicular tumors perhaps is not essential since both
are treated with orchiectomy. As already pointed out by the authors,
it would be more interesting further investigation regarding the value
of MRI in differentiating benign from malignant intratesticular lesions.
The results of this study, however, further strength the utility of
MRI, which should be used whenever sonographic findings are inconclusive
or inconsistent with the clinical findings.
Reference
1. Salamand P, Mianné D, Briant JF, Richez P: An MRI study of primary
testicular tumors. J Radiol. 1998; 79: 865-70.
Dr.
Adilson Prando
Chief, Department of Radiology and
Diagnostic Imaging
Vera Cruz Hospital
Campinas, São Paulo, Brazil |