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

Abstract 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.