Intraluminal rectal cancer metastasis to the small bowel: An extremely rare case report

Metastatic rectal cancer in the ampulla of Vater: A unique case

Background

A metastatic lesion located in the ampulla of Vater is considered extremely rare, with only 32 cases reported globally.

Case

A 65‐year‐old patient was primarily diagnosed with a rectal adenocarcinoma. Twenty‐four months later as part of the oncological follow‐up, the patient was diagnosed with a single secondary tumor in the ampulla of Vater. After undergoing a pancreaticoduodenectomy (Whipple procedure), the patient experienced an uneventful recovery and received adjuvant chemotherapy. Sixteen months later the patient remained disease‐free.

Conclusion

To the best of our knowledge, the present case represents the first reported metastatic tumor in the ampulla of Vater, originating from a rectal adenocarcinoma. This case underlines the critical role of immunohistochemistry in arriving at a correct diagnosis in order to guide clinical decision‐making.

Endoluminal tumor implant of a colorectal cancer in an anal fistula detected by FISH techniques: a case report

Intraluminal shedding of tumor cells is a rare infrequent sporadic colorectal cancer (sCRC) mechanism of spreading. Less than 30 cases of sCRC metastasis into anal fistula have been reported. Here, we study a 72-year-old male with an adenocarcinoma arising in an anal fistula. Subsequent studies revealed another tumor in the rectum without distant metastatic disease; therefore, a curative-intent abdominoperineal resection was performed. The histologic study showed a moderately differentiated adenocarcinoma in both locations. No perineural or lymphovascular invasion was observed, and all the lymphatic nodes resected were negative for malignancy. Both tumors showed positive CK20 and negative CK7 immunostaining, but KRAS G12D mutation was only detected in the rectal tumor. After those conventional studies, a cytogenetic profile of both tumors was performed by interphase fluorescence in situ hybridization (iFISH) techniques. The FISH study displayed an identical genetic profile in both tumors, loss of the chromosomes 8 and 18q, and no alteration in chromosome 7 and 13q. Based on pathological and genetic findings, we established the same clonal origin of both tumors. Currently, the diagnosis of an intraluminal CRC metastasis relies on histologic and immunohistochemistry findings. We suggest that genetic studies at the individual cell level by FISH techniques may be useful in order to differentiate synchronous from intraluminal metastasis.

Metachronous rectal metastasis from primary transverse colon cancer: a case report

Background

Colorectal metastases from primary colorectal cancers are very rare, and little is known about their epidemiological aspects or the best diagnostic and therapeutic strategies. Herein, we report a case of a 65-year-old woman with suspected metachronous metastasis to the rectum from primary transverse colon cancer.

Case presentation

The patient underwent a laparoscopic extended right hemicolectomy for primary transverse colon cancer. Histopathological examination showed moderately differentiated adenocarcinoma, and the tumor was diagnosed as stage IIA (T3, N0, M0). Fifteen months after her colectomy, a computed tomography scan demonstrated a rectal tumor and a right ovarian tumor. Colonoscopy revealed a superficial elevated lesion in the middle rectum, and histological analysis showed moderately differentiated adenocarcinoma. Laparoscopic low anterior resection preserving the left colic artery and bilateral adnexectomy were performed. Histological examination of the rectal tumor showed that adenocarcinoma was mainly present in the submucosa and muscularis propria, while the carcinoma-involved region of the mucosal layer had mucosal colonization representing the spread of metastatic tumor cells along the basement membrane of preexisting crypts and/or villi. The right ovarian tumor proved to be moderately differentiated adenocarcinoma that was positive for cytokeratin 20 and negative for cytokeratin 7 staining, indicating metastasis from the colorectal cancer. The rectal and ovarian tumors were similar to transverse colon cancer in architectural and cytological atypia. Both adenocarcinomas of the transverse colon and rectum were negative for p53 in immunohistochemical staining and RAS wild type in genetic assessment. These findings support a possible diagnosis of rectal and ovarian metastasis from the primary transverse colon cancer. The patient recovered well after surgery, and neither relapse nor metastasis was observed 18 months after surgery.

Conclusion

Distinguishing primary from metastatic colorectal cancer can be challenging, but a comprehensive evaluation of histological features, clinical history, and tumor distribution can enable making a correct diagnosis and implementing optimal treatment.