A Rare Case of Atrial Metastasis From a Rectal Adenocarcinoma.

Colorectal cancers typically metastasize to the lymph nodes, liver or lungs. Metastasis to the heart is rare and although a few cases of cardiac metastases from colon cancer are described in the literature, cases of metastatic rectal cancer to the heart are far fewer. A 69-year-old woman with a history of rectal adenocarcinoma treated with neo-adjuvant chemotherapy and radiation, followed by resection and adjuvant chemotherapy, presented with increasing dyspnea on exertion and lower extremity edema 5 years after oncology follow-up. Echocardiography revealed a mass within the right atrium, which was biopsied and found to be consistent with metastatic rectal adenocarcinoma and a thrombus. The patient was deemed to be a poor surgical candidate given her co-morbidities and overall prognosis. Chemotherapy was offered and refused by the patient. The medical literature has a paucity of similar cases of rectal adenocarcinoma metastasizing to the right atrium. Further studies are needed to help guide standardized treatment options.

Disruption of CHTF18 causes defective meiotic recombination in male mice.

CHTF18 (chromosome transmission fidelity factor 18) is an evolutionarily conserved subunit of the Replication Factor C-like complex, CTF18-RLC. CHTF18 is necessary for the faithful passage of chromosomes from one daughter cell to the next during mitosis in yeast, and it is crucial for germline development in the fruitfly. Previously, we showed that mouse Chtf18 is expressed throughout the germline, suggesting a role for CHTF18 in mammalian gametogenesis. To determine the role of CHTF18 in mammalian germ cell development, we derived mice carrying null and conditional mutations in the Chtf18 gene. Chtf18-null males exhibit 5-fold decreased sperm concentrations compared to wild-type controls, resulting in subfertility. Loss of Chtf18 results in impaired spermatogenesis; spermatogenic cells display abnormal morphology, and the stereotypical arrangement of cells within seminiferous tubules is perturbed. Meiotic recombination is defective and homologous chromosomes separate prematurely during prophase I. Repair of DNA double-strand breaks is delayed and incomplete; both RAD51 and γH2AX persist in prophase I. In addition, MLH1 foci are decreased in pachynema. These findings demonstrate essential roles for CHTF18 in mammalian spermatogenesis and meiosis, and suggest that CHTF18 may function during the double-strand break repair pathway to promote the formation of crossovers.