PMC6201176_01
(a) Sagittal T2-weighted MR demonstrates a heterogenous high-signal mass
(asterisk) located posterior to the urinary bladder (black arrow). The
dominant mass is separated from the cervix (five-pointed star) by a small
amount of fluid. (b) Axial T2-weighted image demonstrates most portions of
the mass (asterisk) to be primarily high signal with relatively small areas
of fluid. (c) Axial T1-weighted precontrast image demonstrates predominantly
low signal intensity throughout the mass (asterisk). (d) 3 min delayed
post-contrast T1-weighted image demonstrates persistent heterogeneously
moderate enhancement in portions of the dominant mass (asterisk).
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The ill-defined mass did not appear to be originating from the cervix and ovaries (Figure 1(a)). T2-weighted image demonstrates most portions of the mass (asterisk) to be primarily high signal with relatively small areas of fluid (Figure 1(b)). T1-weighted image demonstrates homogeneous low-signal intensity through the whole mass (Figure 1(c)), while portions of the tumor presented heterogeneously moderate enhancement on contrast-enhanced T1-weighted imaging (Figure 1(d)).
(a) On laparotomy, the abdomen and pelvis was found to be completely occupied
by a huge multilobate mass that were surrounded by omentum and colon. (b)
Large amounts of amorphous, gelatinous tissue were invested within all
compartments of the intraperitoneal spaces. (c) Pseudocapsule around the
tumor was ruptured and tissue with whitish-/yellowish-colored appearance
flowed out.
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On laparotomy, the mass surrounded by omentum and colon extended from the pelvic cul-de-sac to a portion of hemidiaphragm (Figure 2(a)). Large amounts of amorphous, gelatinous tissue were invested within all compartments of the intraperitoneal spaces (Figure 2(b)), but no clear site of origin was recognized. During the procedure, pseudocapsule around the tumor was ruptured and tissue with whitish-/yellowish-colored appearance flowed out (Figure 2(c)).
(a) Most of the neoplastic cells demonstrated polygonal morphology with short
spindled shape to more rounded cells in myxoid stroma and varying amounts of
eosinophilic cytoplasm. Furthermore, polynuclear cells and cells with
bizarrely enlarged nuclei (arrow indicated) could be detected (HE staining;
magnification x20). (b) IHC demonstrated a malignant spindle cell neoplasm
positive for smooth muscle actin (Envision: magnification x20). (c) IHC
showed strong positive staining for desmin (Envision: magnificationx20). (d)
IHC showed moderate cytoplasmic staining for MyoD1 in
morphologically-appearing rhabdomyoblasts (Envision: magnification x10). (e)
IHC presented focal positive staining for ER (Envision: magnification x5).
(f) The Ki67 proliferation index was 60%-70% (Envision: magnification
5x).
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Furthermore, polynuclear cells and cells with bizarrely enlarged nuclei could be detected (Figure 3(a)). Immunohistochemical (IHC) analysis demonstrated strongly positive staining for smooth muscle actin (Figure 3(b)) and Desmin (Figure 3c), moderate staining for MyoD1 in morphologically appearing rhabdomyoblasts (Figure 3(d)), and focal positive staining for ER (Figure 3(e)), consistent with a diagnosis of RMS. The Ki67 proliferation index reached as high as 70% (Figure 3(f)).