LAUSR

A 61-year-old man was referred to our centre with right scrotal pain, swelling and dysuria for 3 weeks. He was afebrile. He had been previously treated with antibiotics for presumptive epididymo-orchitis. He had previously undergone laparoscopic anterior resection 8 months ago with adjuvant chemotherapy for moderately differentiated sigmoid colon carcinoma (T3N2M0). Margins were negative post resection. Physical examination of the abdomen was unremarkable. A 2-cm hard mass was felt in the right iliac fossa port site wound. A firm mass, separate and anterior to the testis was felt in the right scrotum. The right spermatic cord was thickened and hard. The left scrotum was normal. Tumour markers for scrotal tumours were all in the normal range. A scrotal ultrasound revealed a normal right testis with simple hydrocele. However, along the right inguinal canal from the right iliac fossa surgical port leading to the right epididymis, there were numerous irregularly shaped non-hyperaemic soft tissue nodules (Fig. 1). This suggested metastatic colorectal carcinoma. The spread of the cancer from the right iliac fossa surgical port site along the right spermatic cord to the right epididymis was due to a patent processus vaginalis (PPV). Initial surveillance computed tomographic scan 4-months post sigmoido-colectomy showed features of post-treatment changes. However, this time, the computed tomographic scan showed a 3.1 × 2.1 cm mass extending from the serosal surfaces of the anastamotic sites. A 2.4 cm enhancing nodule was seen in the subcutaneous fat layer of the abdominal wall suggestive of metastasis. Numerous enhancing nodules were seen to be tracking along the right inguinal canal from the right iliac fossa surgical port site to the right epididymis (Fig. 2). A large right hydrocele was noted. This patient was diagnosed with metastatic colorectal carcinoma with port-site metastases and was urgently referred to medical oncology for palliative chemotherapy. The prevalence of PPV in adult life has been found to be 15–30% in autopsies but in a later study, van Veen et al. reported that the incidence of PPV in adults is approximately 12%. This provides a possible passage of intraperitoneal contents such as blood following splenic rupture, peritoneal dialysis fluid or intraperitoneal abscesses to flow between the abdomen and the scrotum, and 20% of patients with PPV may present with inguinal hernia or hydrocele. In terms of metastasis, there are also reports of epithelial mesothelioma of the peritoneum and gastric cancer disseminated to the scrotal via the PPV. In our case, the PPV acted as a conduit for tumour seeding from the port site resulting in an unusual manifestation as scrotal pathology in the right with hydrocele. Port site metastases (PSM) after laparoscopic surgery for colorectal cancer was first described in 1993. By the 2000s, the incidence had drastically dropped from 20% to around 1%. PSMs are early tumour recurrence that usually develop locally in the abdominal wall, at the site of the port incision. However, in our case, the PSM not only recurred at the trocar incision site but also invaded into the scrotal region via PPV. This local invasion of the tumour from the port site to the scrotal region suggests the possibility of contamination by laparoscopic instruments, further made possible by the presence of a PPV which serves a conduit between the abdominal space and the scrotal region. Proper selection of patients for laparoscopic surgery and a skilled laparoscopic surgical team with adequate surgical techniques are efficient measures to reduce the incidence of PSM. Committing to