Solitary mediastinal lymph node metastasis in rectosigmoid carcinoma: a case report
© Musallam et al; licensee BioMed Central Ltd. 2008
Received: 06 July 2008
Accepted: 31 July 2008
Published: 31 July 2008
Colorectal cancer most commonly metastasizes to the regional lymph nodes, liver, bone, lung, and brain. Metastases to mediastinal lymph nodes is a rare entity which has never been reported to be solitary.
We herein describe a 67-year-old male patient with a solitary mediastinal lymph node metastasis three years following the resection of his primary rectosigmoid carcinoma. Pathological characteristics of the metastatic tissue and technical limitations in imaging modalities resulted in incongruity between follow-up CT and PET scans. Diagnosis of this distant metastasis has been confirmed through a mediastinoscopic biopsy.
Attention should be paid to the mediastinum when evaluating PET scan or CT films during follow-up of patients with colorectal cancer. Using PET/CT instead of separate morphological and functional data sets favors better detection. Questions still remain concerning the ideal management protocol of such a presentation, the two main options being locoregional or chemotherapeutic.
Colorectal cancer is the third most common cancer as well as the third most common cause of cancer death in both men and women . Rectosigmoid colon continues to be the most common site while the cecum, ascending and transverse colon are increasingly reported. Colorectal cancer most commonly metastasizes to the regional lymph nodes, liver, bone, lung, and brain. Rare metastases to mediastinal lymph nodes from colonic carcinomas have also been reported [2–5]. Postulated mechanisms of spread were lymphatic drainage routes of the liver in those with concurrent liver metastases; and paravertebral venous or paraaortic lymphatic plexus in those with concomitant pelvic or abdominal metastases. Mediastinal lymphadenopathy, attributed to coexisting sarcoidosis, has also been reported in one case of colon cancer . To our knowledge, our report is the first in the literature to demonstrate solitary mediastinal lymph node metastases of colorectal carcinoma with no other site involvement.
We propose the following explanations for the incongruity between the follow-up imaging studies performed on the patient described in this report. 18F-FDG PET scan has proven superior to morphologic imaging procedures when assessing lymph node involvement based on functional data evaluating tumor metabolism . A meta-analysis of the most recent literature showed that changing the therapy plan by the use of 18F-FDG PET scan in patients with colorectal metastatic cancer occurs in 31.6% of the cases . However, small malignant lesions may not show increased tracer uptake since current PET-detectors provide an in-plane spatial resolution of only 4–5 mm. This limitation is most heightened in the thorax where lesion detection on PET is further compromised by respiratory motion (shallow breathing during PET acquisition) . Furthermore, the extensive fibrosis evident by pathological examination of the mediastinal lymph node in our case might have led to a decrease in uptake of 18F-FDG during the initial PET scan in April 2006. Several studies, evaluating patients with different oncological diseases, have reported outstanding results concerning tumor staging when using PET/CT instead of separate morphological and functional data sets [10, 11].
Upgrading from stage III to stage IV ensues after detection of this distant metastasis. However, one question still remains: should the management of this patient rely on systemic chemotherapy only or could the patient benefit from loco-regional radiation and/or surgical resection? The rationale would be that resection or radiation of the mediastinal lymph node may prevent possibly fatal complications caused by tracheal and major vascular involvement; however, no evidence to support this reasoning currently exists.
Our case report suggests that attention should be paid to the mediastinum when evaluating PET scan or CT films during follow-up of patients with colorectal cancer. Moreover, despite the fact that the 18F-FDG PET scan has high specificity for colorectal metastases; all suspected lesions, identified though morphological imaging, must be further investigated if they can change the therapeutic plan. However, the choice between locoregional and chemotherapeutic subsequent management remains unclear in the case of solitary mediastinal metastasis.
Written informed consent was obtained from the patient for publication of this Case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
- 18F-FDG PET:
18-F-fluorodeoxyglucose positron emission tomography
Thyroid transcription factor-1.
- Jemal A, Siegel R, Ward E, Murray T, Xu J, Thun MJ: Cancer statistics, 2007. CA Cancer J Clin. 2007, 57: 43-66.View ArticlePubMedGoogle Scholar
- August DA, Sugarbaker PH, Schneider PD: Lymphatic dissemination of hepatic metastases: implications for the follow-up and treatment of patients with colorectal cancer. Cancer. 1985, 55: 1490-1494. 10.1002/1097-0142(19850401)55:7<1490::AID-CNCR2820550712>3.0.CO;2-N.View ArticlePubMedGoogle Scholar
- Vetto JT, Cohen AM: Isolated spread of hepatic metastatic disease to a mediastinal lymph node: report of a case and review of pertinent anatomy and literature. Dis Colon Rectum. 1991, 34: 1128-1130. 10.1007/BF02050077.View ArticlePubMedGoogle Scholar
- Kuba H, Sato N, Uchiyama A, Nakafusa Y, Mibu R, Yoshida K, Kuroiwa KA, Tanaka M: Mediastinal lymph node metastasis of colon cancer: report of a case. Surg Today. 1999, 29: 375-377. 10.1007/BF02483068.View ArticlePubMedGoogle Scholar
- Tsubaki M, Nemoto K, Yoda N: Sigmoid colon cancer with mediastinal lymph node metastases. Int Surg. 2007, 92: 209-213.PubMedGoogle Scholar
- Malani A, Gupta C, Singh J, Rangineni S: A 63-year-old woman with colon cancer and medisatinal lymphadenopathy. Chest. 2007, 131: 1970-1973. 10.1378/chest.06-1951.View ArticlePubMedGoogle Scholar
- Gambhir SS, Czernin J, Schwimmer J, Silverman DH, Coleman RE, Phelps ME: A tabulated summary of the FDG PET literature. J Nucl Med. 2001, 42: 1S-93S.PubMedGoogle Scholar
- Wiering B, Krabbe PF, Jager GJ, Oyen WJ, Ruers TJ: The impact of fluor-18-deoxyglucose-positron emission tomography in the management of colorectal liver metastases. Cancer. 2005, 104: 2658-2670. 10.1002/cncr.21569.View ArticlePubMedGoogle Scholar
- Veit P, Ruehm S, Kuehl H, Stergar H, Mueller S, Bockisch A, Antoch G: Lymph node staging with dual-modality PET/CT: Enhancing the diagnostic accuracy in oncology. Eur J Radiol. 2006, 58: 383-389. 10.1016/j.ejrad.2005.12.042.View ArticlePubMedGoogle Scholar
- Antoch G, Vogt FM, Freudenberg LS, Nazaradeh F, Goehde SC, Barkhausen J, Dahmen G, Bockisch A, Debatin JF, Ruehm SG: Whole-body dual modality PET/CT and whole-body MRI for tumor staging in oncology. JAMA. 2003, 290: 3199-3206. 10.1001/jama.290.24.3199.View ArticlePubMedGoogle Scholar
- Cohade C, Osman M, Leal J, Wahl RL: Direct comparison of (18) FFDG PET and PET/CT in patients with colorectal carcinoma. J Nucl Med. 2003, 44: 1797-1803.PubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.