Retroperitoneal Ancient Schwannoma

Neda Najmi, MD; E Isin Akduman, MD


Appl Radiol. 2021;50(6):45-47. 

In This Article

Imaging Findings

Magnetic resonance imaging (MRI) of the pelvis revealed a 5cm right retroperitoneal cystic mass. The mass was primarily isointense to muscle on T1 images (Figure 1) and hyperintense on T2 images (Figure 2). Thick-walled rim enhancement followed gadolinium administration (Figure 3). There was no diffusion restriction.

Figure 1.

Axial T1 MRI of pelvis demonstrates a well-circumscribed mass that is isointense to muscle in the right hemipelvis.

Figure 2.

Coronal T2 MRI of pelvis demonstrates a hyperintense cystic mass with thick wall rim in the right hemipelvis. There is no lymphadenopathy. The mass is separate from the adnexa.

Figure 3.

Coronal (A) and sagittal (B) postcontrast T1 MRI of the pelvis demonstrate a thick-walled rim enhanced cystic mass with central necrosis in the right hemipelvis and associated with mild regional mass effect on the posterior aspect of the uterus.

A 5.4 × 5.3 × 5.0 cm capsulated cystic mass was excised via an open transperitoneal technique. Histologic examination revealed a poorly cellular, bland neoplasm in variably dense fibrotic stroma. The cells were narrow and elongated with tapered ends interspersed with collagen fibers. Mitotic figures were not identified in the mass. Immunohistochemical staining was strongly and diffusely positive (3+, 100%) for S100, and negative for CD 34 and desmin.