Two cases of Wolffian tumor with novel magnetic resonance imaging findings reflecting characteristic pathology.

A Wolffian tumor is a rare tumor arising from the remnants of the mesonephric duct. Herein, we report two cases. A 61-year-old woman presented with swollen left adnexa. On T2 weighted magnetic resonance imaging (MRI), a 4.4 cm solid pelvic mass showed slightly high signal intensity, with a low-signal-intensity rim. Microscopically, cuboidal cells with bland nuclei were arranged in a dense tubular form. A 40-year-old woman complained of lower abdominal pain. On T2 weighted MRI, a 6.0 cm solid mass with a low-signal-intensity rim was found. The pathology of the resected tumor was similar to that of case 1. Both cases were diagnosed as Wolffian tumor. The rims of the tumors in both cases were composed of eosinophilic spindle-shaped cells immunoreactive to alpha-smooth muscle actin and desmin, identical to the smooth muscle cells surrounding the mesonephric duct remnants. MRI findings reflecting smooth muscle rims might contribute to an accurate preoperative diagnosis of this rare tumor.