The angiographic anatomy of the small arteries and their collaterals in colorectal resections: some insights into anastomotic perfusion.

OBJECTIVE: The aim of this study was to examine by screening angiography the anatomy of the small arteries and their collaterals in colorectal resections in order to identify factors that might be implicated in anastomotic leak. SUMMARY BACKGROUND DATA: Anastomotic leak is more frequent following low anterior resection. Vascular compromise is frequently implicated but poorly understood as a mechanism. METHODS: High definition screening angiography was performed on 17 colorectal resection specimens. RESULTS: (1) The small arteries of the colon (the vasa recta that arise from the marginal artery) show variability in their spacing and in their collaterals based on their anatomical positions. At the splenic flexure and the proximal and mid descending colons, the vasa recta are spaced 2-cm apart and have few collaterals. At the right, transverse, distal descending and sigmoid colons, the vasa recta are spaced <1 cm apart and have more extensive collaterals. (2) The small arteries of the rectum are spaced <1 cm apart and also show variability in their collaterals based on their anatomical level. In the mid-to-upper rectum there are good collaterals between the small arteries within the mesorectum based upon the bifurcation of the superior rectal artery and its main branches. In the lower rectum, however, there are only a few and very variable intramural collaterals between the small arteries. CONCLUSIONS: Based on these findings, unrecognized disruption of small artery collaterals during colorectal resection might be implicated in anastomotic leak and in particular might explain the higher leak rate in low anterior resection.

Metastatic prostate cancer masquerading clinically and radiologically as a primary caecal carcinoma.

BACKGROUND: Prostatic carcinoma is the second most common cause of cancer-related deaths in males in the West. Approximately 20% of patients present with metastatic disease. We describe the case of a patient with metastatic prostate cancer to the bowel presenting clinically and radiologically as a primary caecal cancer. CASE PRESENTATION: A 72 year-old man presented with abdominal discomfort and a clinically palpable caecal mass and a firm nodule on his thigh, the latter behaving clinically and radiologically as a lipoma. Computed tomographic (CT) scan showed a luminally protuberant caecal mass with regional nodal involvement. The patient was being treated (Zoladex) for prostatic cancer diagnosed 6 years previously and was known to have bony metastases. On admission his PSA was 245.4 nmol/ml. The patient underwent a right hemicolectomy. Histology showed a poorly differentiated adenocarcinoma which was PSA positive, confirming metastatic prostatic adenocarcinoma to the caecum. The patient underwent adjuvant chemotherapy and is free from recurrence a year later. CONCLUSION: Metastasis of prostatic carcinoma to the bowel is a very rare occurrence and presents a challenging diagnosis. The diagnosis is supported by immunohistochemistry for PSA. The treatment for metastatic prostate cancer is mainly palliative.