Needle track seeding:A real hazard after percutaneous radiofrequency ablation for colorectal liver metastasis

Neoplastic needle track seeding following percutaneous radiofrequency ablation(RFA)of secondary liver tumors is exceedingly rare.Reports on cutaneous tumor seeding after percutaneous RFA for colorectal liver metastasis are even rarer in the literature.Here we report a case of a 46-year-old female who developed an ulcerating skin lesion along the needle track of a previous percutaneous RFA site around 6 mo after the procedure.The previous RFA was performed by the LeVeen needle for a secondary liver tumor from a primary rectal cancer.The diagnosis of secondary skin metastasis was confirmed by fine needle aspiration cytology.The lesion was successfully treated with wide local excision.We believe that tumor seeding after percutaneous RFA in our patient was possibly related to its unfavorable subcapsular location and the use of an expansion-type needle.Hence,prophylactic ablation of the needle track should be performed whenever possible.Otherwise,alternative routes of tumor ablation such as laparoscopic or open RFA should be considered.

Catheter tract implantation metastases associated with percutaneous biliary drainage for extrahepatic cholangiocarcinoma

AIM： To estimate the incidence of catheter tract implantation metastasis among patients undergoing percutaneous transhepatic biliary drainage （PTBD） for extrahepatic cholangiocarcinoma, and to provide data regarding the management of this unusual complication of PTBD by reviewing cases reported in the literature. METHODS： A retrospective analysis of 67 consecutive patients who underwent PTBD before the resection of extrahepatic cholangiocarcinoma was conducted. The median follow-up period after PTBD was 106 too. The English language literature （PubMed, National Library of Medicine, Bethesda, MD, USA）, from .lanuary 1966 through December 2004, was reviewed. RESULTS： Catheter tract implantation metastasis developed in three patients. The cumulative incidence of implantation metastasis reached a plateau （6%） at 20 mo after PTBD. All of the three patients with implantation metastasis died of tumor progression at 3, 9, and 20 mo after the detection of this complication. Among the 10 reported patients with catheter tract implantation metastasis from extrahepatic cholangiocarcinoma （including our three patients）, two survived for more than 5 years after the excision of isolated catheter tract metastases. CONCLUSION： Catheter tract implantation metastasis is not a rare complication following PTBD for extrahepatic cholangiocarcinoma. Although the prognosis for patients with this complication is generally poor, the excision of the catheter tract may enable survival in selected patients with isolated metastases along the catheter tract.

Orthotopic transplantation model of human gastrointestinal cancer and detection of micrometastases

AIM: To establish a relevant animal model of human gastrointestinal cancer, which can be used for repetitive investigations, so as to improve our understanding and management of carcinogenesis and cancer metastasis. METHODS: Intact tissues of human colorectal and pancreatic cancers were transplanted in nude mice. The biological characteristics of the original and the corresponding transplanted tumors were investigated by HE staining, PAS staining and immunostaining. The metastases in the livers and lungs of nude mice were investigated by immunostaining with biotinylated mab KL-1 and by RT-PCR using CK20 specific primers. RESULTS: There were totally 9 of 16 surgical specimens growing in nude mice subcutaneously and/or orthotopically (4 of 6 colorectal and 5 of 10 pancreatic cancer). Tumor cell content of the specimens and freezing of tissue specimens are important factors influencing the growth of transplanted tumor. In the group of fresh tumor tissues with greater than 50% tumor cell content, the success rate of the transplantation was 100% (3 cases of pancreatic cancer and 3 cases of colorectal cancer). The orthotopically trans-planted tumors resemble the original tumor morphologically and biologically, including TAA expression such as CEA by immunohistochemistry, and CEA level in the serum of mice. Ki-67 labeling index and the expression of TAA especially K-ras, 17-1A and RA-96, are associated with the potential of tumor growth in nude mice. Micrometastases in the lungs and livers of tumor bearing mice can be detected by immunostaining with biotinylated mab KL-1 and CK20-specific RT-PCR. CONCLUSION: An orthotopic transplantation model for human colon and pancreatic cancer in nude mice has been set up. We have also established sensitive detection methods with CK-immunohistochemistry and CK20-RT-PCR to study xenotransplanted human cancer and its metastatic cancer cells in the liver and lung of nude mice. This study may be helpful in understanding the mechanism of cancer metastasis and in developing new diagnostic methods and therapeutic strategies for metastases including micrometastases.

Late recurrence of papillary thyroid cancer from needle tract implantation after core needle biopsy: A case report

BACKGROUND Papillary thyroid cancer(PTC)has good prognosis so that the local recurrence or distant metastasis can occur later on the lifetime follow up.In this study,we report recurrence of PTC in subcutaneous area combined with lymph node metastasis.A suspicion of needle tract implantation after core needle biopsy was found.CASE SUMMARY A 66-year-old female patients who underwent right thyroid lobectomy for PTC complained of palpable nodule on anterior neck area.The location of the palpable nodule was not associated with her postoperative scar.After excision of the skin tumor,it was diagnosed as recurrence of PTC.Furthermore,results of subsequent imaging showed lymph node metastasis on her right cervical area.According to the previous medical records,the patient received core needle biopsy through the neck of the patient midline and hematoma was noted after the procedure.The time interval from the first diagnosis to local recurrence or metastasis to the skin and lymph nodes was ten years.As treatment,the patient underwent lymph node dissection in the right and completion thyroidectomy for radioisotope treatment.CONCLUSION Needle tract implantation can occur after core needle biopsy.Further studies are needed to compare core-needle biopsy and fine-needle aspiration.