[Psoas lymph node metastasis in patients with carcinoma of the uterine cervix]

Enlargement of lymph nodes between the psoas muscle and lumbar spine was demonstrated on CT in three of 14 cases having Stage IIb and III uterine cervical carcinoma with iliac or paraaortic lymphadenopathy. In two of these, the adjacent lumbar vertebral body was destroyed. We define psoas lymph nodes to include all lymph nodes located between the psoas muscle and the spine. Psoas lymph nodes may be divided into upper and lower groups: the upper group distributed along the lumbar arteries above in level of L4-L5 and the lower group distributed along the lumbar branches of the iliolumbar arteries below L5. There appears to be paravertebral communication between these two groups. The region of the psoas lymph nodes should be scrutinized in interpretating CT in patients with malignant pelvic tumors which have already spread to iliac or paraaortic lymph nodes. Obliteration of fat plane between psoas muscle and lumbar vertebra is a clue to the presence of enlargement of the psoas lymph nodes on CT. Massive enlargement of psoas lymph nodes may be difficult to distinguish from metastasis to psoas muscle. In such cases, MR imaging would be of help to differentiate these two conditions.