Is port site metastasis a result of systemic involvement?

AIMS: Port site metastasis (PSM) is an unwelcome consequence of laparoscopy for oncological procedures with uncertain etiology. We present the clinical evidence to prove that PSM is likely to be due to the hematogenous spread of tumor cells. MATERIALS AND METHODS: Six cases of port site metastasis, four following laparoscopic radical nephrectomy for localized renal cell carcinoma (RCC), one after laparoscopic radical prostatectomy done in two patients and one after laparoscopic partial cystectomy for tumor at bladder dome done in two were studied. One case of metastatic RCC with bilateral gluteal masses and two cases of open radical nephrectomy, with recurrence at the drain and incision site were also studied. RESULTS: During the median follow up of 59 months (range 24–120), 4/136 patients with RCC (1.47%) developed port site metastasis between 7–36 months after surgery. All six cases of PSM had advanced disease and recurrences at other sites, that is, peritoneum, omentum, bones, and lungs. None of the patients had isolated PSM. One patient of metastatic RCC, who did not have any intervention but repeated intramuscular injections of analgesics-developed bilateral gluteal masses, confirmed to be RCC on fine needle aspiration cytology. Two patients had metastasis at the incision site (one at the drain site) with distance, including cutaneous metastases. CONCLUSIONS: Port site metastasis did not develop in isolation. There could be a likely existence of circulating tumor cells at the time of surgical trauma of penetrating nature, that is, port site or injection site, which manifest in some patients depending upon their immune response.