Rectal cancer presenting with erythema ab igne

A 45-year-old tugboat worker presented to his general practitioner with a four-month history of anal pain and bleeding per rectum. A diagnosis of haemorrhoids was initially made. He then re-presented with additional symptoms of tenesmus, ‘wet wind’, weight loss and pelvic pain so was promptly referred to colorectal outpatient clinic. On further questioning, he described prolonged use of a hot water bottle to ease his worsening localized pain. He had no focal neurological symptoms and signs in his lower limbs, and no indication of pelvic autonomic dysfunction. Clinical inspection of his buttocks revealed erythema ab igne (Figure 1) though abdominal examination and digital rectal examination were unremarkable. Of significance, rigid sigmoidoscopy was inconclusive as it revealed stool mixed with blood in the rectum, obscuring views of the mucosa. A subsequent flexible sigmoidoscopy demonstrated a circumferential, near-obstructing lesion 10 cm from the anal verge. Representative biopsies of the lesion were taken. After considering a colorectal stent the patient opted to have the colon proximal to the lesion defunctioned laparoscopically. Magnetic resonance imaging (MRI) confirmed a circumferential tumour commencing 9 cm from the anal verge, extending 10 cm proximally into the distal sigmoid (Figure 2). The lesion had breached the rectal wall at several locations, reaching the mesorectal fascia. There was no apparent neural involvement. A staging computed tomogram (CT) showed multiple peri-rectal nodes and two tiny putative liver metastases which were not amenable to biopsy. Radiological staging was thus T3 N2 M1 (assuming the liver lesions to be metastatic). The histology of the lesion confirmed moderately differentiated invasive adenocarcinoma of colorectal origin. Following his successful laparoscopic defunctioning colostomy the patient recovered satisfactorily and was discharged within one week. He has now commenced chemoradiotherapy with a view to definitive curative surgery after neo-adjuvant treatment.