Destructive soft tissue metastases in advanced colorectal cancer: a case report

Abstract

Extremity soft tissue metastases are a rare, but recognised complication of advanced colon cancer. There is limited data regarding their management, and such metastases are associated with a poor prognosis. The investigation of such metastases may require full-body positron emission tomography (PET) scanning, rather than per-protocol PET scanning. We present the case of a 76-year-old incarcerated male with a history of T4b N1b M0 right colon adenocarcinoma, who presented with right distal thigh pain and gross disfigurement. MRI demonstrated an erosive, verrucous soft tissue lesion, which had not been present on the diagnostic, per-protocol PET scan. Whole-body PET scan subsequently confirmed a highly avid lesion, with biopsy confirming metastatic adenocarcinoma consistent with colonic origin. The patient’s pain was treated with multimodal analgesia and radiotherapy. Despite these interventions, locoregional symptoms from the extremity metastasis were difficult to control. The patient died 4 months following the diagnosis of metastatic disease. This case highlights the importance of recognising extremity soft tissue abnormalities as a possible consequence of advanced colon cancer. It illustrates the importance of whole-body PET scanning and explores management complexities that may present when caring for incarcerated patients. The subsequent literature review explores the existing literature regarding extremity soft tissue metastases in colon cancer. Further data regarding both the incidence and optimal management of such lesions is required.