PMC8033224_01
(a) Fluorodeoxyglucose positron emission tomography-computed tomography images showing lesion (arrow) involving anterior urethra along with corpus spongiosum; histopathology slides show (b) poorly differentiated small, round cells with scanty cytoplasm without nuclear molding and many mitotic figures; (c) Immunohistochemistry staining with strong mic-2 expression; (d) Nkx2.2 strong diffuse nuclear staining; and (e) fluorescence in situ hybridization for EWSR1 gene rearrangement shows an interphase cell showing 1 fusion, 1 green, and 1 orange signal
IJU-37-84-g001.jpg
PMC8033224_01_IJU-37-84-g001.jpg
F1
T1-weighted imaging with patchy irregular peripheral enhancement on contrast scan. The patient underwent a cystourethroscopy, which showed a pedunculated mass arising from the right half of bulbar and penile urethra almost obliterating the lumen. The biopsy revealed a small, round cell tumor. 18F-fluorodeoxyglucose whole-body positron emission tomography-computed tomography (PET-CT) scan [Figure 1a] showed hypermetabolic lesion involving the entire length of the penile urethra up to bulbous urethra with a predominance on the right side and no uptake in lymph nodes or distant organs. Histopathological examination of total penectomy specimen showed [Figure 1b] sheets of small, round, blue cells with scanty cytoplasm without any nuclear molding, few tumor rosettes, and many mitotic figures. On immunohistochemistry (IHC, Figure 1c and d), cells expressed vimentin, Fli1, NKX 2.2, and mic-2. The fluorescence in situ hybridization (FISH) analysis showed a rearrangement of the EWSR1 gene locus in 96% of the tumor cells [Figure 1e; done with ZytoLight SPEC EWSR1 Dual Color Breakapart Probe Kit, analyzed on an Olympus BX51 fluorescent microscope using Applied Spectral Imaging Software].