Magnetic resonance imaging findings of cellular angiofibroma of the tunica vaginalis of the testis: a case report

Abstract

Background: Cellular angiofibroma represents a rare mesenchymal tumor typically involving the inguinoscrotal area in middle-aged men. Although the origin of this benign tumor is unknown, it is histologically classified as an angiomyxoid tumor. Cellular angiofibroma is characterized by a diversity of pathological and imaging features. An accurate preoperative diagnosis is challenging. Magnetic resonance imaging examination of the scrotum has been reported as a valuable adjunct modality in the investigation of scrotal pathology. The technique by providing both structural and functional information is useful in the differentiation between extratesticular and intratesticular diseases and in the preoperative characterization of the histologic nature of various scrotal lesions. There are few reports in the English literature addressing the magnetic resonance imaging findings of cellular angiofibroma of the scrotum and no reports on functional magnetic resonance imaging data. Here we present the first case of a cellular angiofibroma arising from the tunica vaginalis of the testis and we discuss the value of a multiparametric magnetic resonance protocol, including diffusion-weighted imaging, magnetization transfer imaging and dynamic contrast-enhanced magnetic resonance imaging in the preoperative diagnosis of this rare neoplasm.

Case presentation: A 47-year Greek man presented with a painless left scrotal swelling, which had gradually enlarged during the last 6 months. Magnetic resonance imaging of his scrotum displayed a left paratesticular mass, in close proximity to the tunica vaginalis, with heterogeneous high signal intensity on T2-weighted images and no areas of restricted diffusion. The tumor was hypointense on magnetization transfer images, suggestive for the presence of macromolecules. On dynamic contrast-enhanced magnetic resonance imaging the mass showed intense heterogeneous enhancement with a type II curve. Magnetic resonance imaging findings were strongly suggestive of a benign paratesticular tumor, which was confirmed on pathology following lesion excision.

Conclusions: Magnetic resonance imaging of the scrotum by combining conventional and functional magnetic resonance data provides useful diagnostic information in the preoperative characterization of scrotal masses. A possible diagnosis of a benign paratesticular tumor based on magnetic resonance imaging features may improve patient care and decrease the number of unnecessary radical surgical explorations.

Keywords: Cellular angiofibroma; Diffusion-weighted MRI; Magnetic resonance; Magnetization transfer contrast imaging; Tunica vaginalis.

Fig. 1

Transverse T1-weighted image shows a well-demarcated left paratesticular mass, lying adjacent to the scrotal wall. The lesion (arrowhead) demonstrated mainly similar signal intensity, when compared to the ipsilateral displaced testis (arrow). Significant left hydrocele (long arrow) was also observed

Fig. 2

Transverse T2-weighted image demonstrates left paratesticular tumor heterogeneity. The mass (arrowhead) was slightly hyperintense when compared to the ipsilateral testicular parenchyma (arrow). Left hydrocele (long arrow)

Fig. 3

Apparent diffusion coefficient map in axial plane (b = 900 mm²/second). The lesion appears hyperintense, a finding suggestive for the absence of restricted diffusion. The apparent diffusion coefficient value of the mass (arrowhead) was 2.34×10⁻³ mm²/second. The apparent diffusion coefficient values of left (arrow) and right testes (not shown on image) were 0.99×10⁻³ mm²/second and 1.04×10⁻³ mm²/second, respectively. The presence of densely packed seminiferous tubules lined by a compact fibroelastic connective tissue sheath and separated by cellular interstitial stroma explains the restricted diffusion of the normal testis. Large left hydrocele

Fig. 4

Axial three-dimensional gradient-echo magnetic resonance image before (a) and after (b) the application of the magnetization transfer prepulse. The magnetization transfer ratio (in percent) of the left paratesticular mass (arrowhead) was 44.6, similar to that of the contralateral normal testis (46 %, not shown on images). The left testis (arrow) was displaced and compressed and the measurement of the magnetization transfer ratio was impossible due to artifacts. Left hydrocele (long arrow)

Fig. 5

a Coronal dynamic contrast-enhanced subtracted image at early phase (180 seconds) and the corresponding time–signal intensity curves of the b left paratesticular mass and the c ipsilateral testis. The tumor (arrowhead, a) enhanced strongly and heterogeneously, showing an initial upstroke followed by a plateau in the late contrast-enhanced phase (type II curve, b). Dynamic contrast-enhanced magnetic resonance findings were strongly suggestive of benignity. Left testis (not shown on image) showed a linear increase of contrast enhancement throughout the examination (type I curve, c). Normal contralateral testis (arrow, a). AU arbitrary units

Fig. 6

a Histopathologic evaluation revealed a highly vascularized tumor, composed of bland spindle-shaped cells (hematoxylin and eosin ×100). b The stroma was mostly myxoid (periodic acid–Schiff – Alcian blue ×100)