EP203 - Cutaneous Metastasis of Rectal Adenocarcinoma: A Rare Clinical Presentation

Purpose/Background: Cutaneous metastasis from colorectal cancer is a rare clinical event, typically indicating disseminated disease and poor prognosis. We report the case of a 47-year-old female with recurrent low rectal adenocarcinoma, initially staged as cT2N0M0, proficient mismatch repair (pMMR), who developed local recurrence with suspected metastatic spread, including cutaneous involvement. This report highlights the importance of vigilant surveillance and the prognostic implications of skin metastases in colorectal cancer.

Methods/Interventions: N/A

Results/Outcomes: This case is of a 47-year-old female who was initially diagnosed with low rectal cT2N0M0 pMMR cancer. At an outside facility, she underwent transanal minimally invasive surgery (TAMIS) with full-thickness resection. Postoperatively, she was unfortunately lost to follow-up and presented to hospital 10 months after TAMIS procedure with pelvic pain and rectal bleeding and found to have locally advanced disease on repeat imaging. She was initiated on FOLFOX chemotherapy and completed 12 rounds of treatment. Unfortunately, the patient came to the emergency department shortly thereafter with rectal bleeding and a right posterior calf nodule. She underwent diverting loop colostomy formation along with biopsy of skin nodule, confirming metastatic rectal adenocarcinoma.

This unfortunate clinical presentation highlights the importance of thorough clinical evaluation in patients presenting with local rectal cancer recurrence, with cutaneous metastasis being a rare but plausible clinical manifestation.

Conclusion/Discussion: Colorectal cancer is the third leading cause of cancer mortality worldwide, with metastatic disease present in up to 50% of cases during the disease course. The most common sites of metastasis are the liver, lung, and peritoneum. Cutaneous metastasis from CRC is rare, with reported incidence ranging from 0.8% to 9% depending on series and gender. Most cases are metachronous, developing months to years after initial diagnosis or resection. The rectum is the most common primary site for skin metastases among CRCs. Cutaneous lesions may present as nodules, plaques, or inflammatory masses, and their appearance should prompt thorough metastatic workup. The development of skin metastases is a sentinel event, often associated with rapid disease progression and poor survival. Median time to death after presentation with cutaneous metastasis is 5.5 months, with most patients dying within a year. Treatment of cutaneous metastases, even in the context of widespread disease, may improve overall survival, but the prognosis remains poor.

This case underscores the importance of close surveillance in rectal cancer

Locally Advanced Rectal Cancer
Pelvic MRI showing local invasion into mesorectum and left levator ani muscle with associated pelvic adenopathy