Organ-associated pseudosarcomatous myofibroblastic proliferation with ossification in the lower pole of the kidney mimicking renal pelvic carcinoma: A case report

Figure 1 Imaging examination of our case of renal organ-associated pseudosarcomatous myofibroblastic proliferation. A: Computed tomography showed a heterogeneous mass (indicated with arrows) of 6 cm in diameter at the left pyeloureteral junction; B: Magnetic resonance imaging showed that the left renal pelvis was occupied by a cystic and solid mass (indicated with arrows) with calcification or ossification.

Figure 2 Gross specimen and histological examination of our case of renal organ-associated pseudosarcomatous myofibroblastic proliferation with ossification. A: Longitudinal section of our patient’s kidney showing a gray-white and pink-grey mass, with capsule in the lower pole of the kidney; B: Microscopic view of the renal organ-associated pseudosarcomatous myofibroblastic proliferation staining with hematoxylin eosin (original magnification × 200). The lesions were found to be composed mainly of proliferative fusiform myofibroblasts and inflammatory cells; C, D: Immunohistochemical staining showed positivity for calponin (C) and SATB-2 (D) (Arrows indicate positive cells).