Figure 2. A: Cyst wall containing smooth muscle bundles and lined by squamous and columnar epithelium (H&E, x100). B: The stroma is infiltrated by nests of neoplastic cells with vesicular nuclei and abundant eosinophilic cytoplasm with foci of keratin-like material.
A Post-operative CT scan reveals no gross tumor residue. According to the multidisciplinary team’s recommendation, the patient was decided to undergo radiation therapy similar to the anal canal radiation fields; 36 Gy in 20 fractions to the pelvic and inguinal lymph nodes and then up to 54 Gy to the surgical bed, concurrently with Capecitabine.
Three months after the treatment was completed, she complained of continued pelvic pain. On the pelvic MRI, there was a 23*20*28 mm multi-loculated cystic, solid lesion in the pre-coccygeal space in the midline posterior cavity suspicious of residual disease or recurrence. These results were confirmed by FDG-PET/CT scan; high SUV (17) presacral mass indicating malignancy and also a small soft tissue lesion in the anterior pelvic wall (SUV=6.3) suspicious for metastatic disease. (Figure 3)