Anal cancer with isolated ischial fossa lymph node metastases: A rare entity in the oligometastatic dilemma.

Carcinoma of the anal canal is relatively rare cancer with a low propensity for metastasis. A literature review identifies two cases with ischial fossa metastases from anal cancer. The authors present the case of a 62-year-old male with moderately differentiated squamous cell carcinoma of the anal canal who presented with isolated ischial fossa lymph node (LN) confirmed by fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography and pelvic magnetic resonance imaging. The patient was treated with concurrent chemoradiation. Ischial fossa LN was included in the high-dose radiation volume. Posttreatment imaging showed complete clinical response. This case highlights a rare metastatic site from anal cancer treated successfully with primary chemoradiation and shows an example of tailored treatment approach of oligometastatic disease from anal cancer.