Natural course of an untreated metastatic perirectal lymph node after the endoscopic resection of a rectal neuroendocrine tumor.
Lymph node metastasis is rare in small (i.e., <10 mm) rectal neuroendocrine tumors (NETs). In addition to tumor size, pathological features such as the mitotic or Ki-67 proliferation index are associated with lymph node metastasis in rectal NETs. We recently treated a patient who underwent endoscopic treatment of a small, grade 1 rectal NET that recurred in the form of perirectal lymph node metastasis 7 years later. A 7-mm-sized perirectal lymph node was noted at the time of the initial endoscopic treatment. The same lymph node was found to be slightly enlarged on follow-up and finally confirmed as a metastatic NET. Therefore, the perirectal lymph node metastasis might have been present at the time of the initial diagnosis. However, the growth rate of the lymph node was extremely low, and it took 7 years to increase in size from 7 to 10 mm. NETs with low Ki-67 proliferation index and without mitotic activity may grow extremely slowly even if they are metastatic.
Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Sang Hyung
SH
Kim
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Dong-Hoon
DH
Yang
Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Jung Su
JS
Lee
Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Soyoung
S
Park
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Ho-Su
HS
Lee
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Hyojeong
H
Lee
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Sang Hyoung
SH
Park
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Kyung-Jo
KJ
Kim
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Byong Duk
BD
Ye
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Jeong-Sik
JS
Byeon
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Seung-Jae
SJ
Myung
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Suk-Kyun
SK
Yang
Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Jin-Ho
JH
Kim
Department of Colon and Rectal Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Chan Wook
CW
Kim
Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Jihun
J
Kim
Lymph node; Metastasis; Neuroendocrine tumor; Rectum