Squamous cell carcinoma of unknown primary in the pelvis after complete remission following chemoradiotherapy: A case report

Figure 1 Images. A: Axial T1-weighted magnetic resonance imaging showing a right-sided perirectal mass adjacent to the levator ani muscle shown by arrow; B: Fluorodeoxyglucose-positron emission tomography/computed tomography demonstrating a solitary hypermetabolic lesion in the pelvis shown by arrow, without evidence of distant disease; C: Hematoxylin and eosin-stained section showing poorly differentiated squamous cell carcinoma under 40 × magnification; D: Immunohistochemical staining positive for p40, consistent with squamous cell origin.