Eur Radiol (2006) 16: 2126–2127DOI 10.1007/s00330-006-0167-8 LETTER TO THE EDITOR

Makoto ShinotoKousei IshigamiKengo YoshimitsuSatoshi AmadaHiroshi Honda

Received: 14 December 2005Accepted: 17 January 2006Published online: 17 March 2006# Springer-Verlag 2006

Posterior iliac crest lymph node metastasisfrom ovarian cancer 15 years after surgery:a mimicker of primary retroperitoneal tumor

M. Shinoto . K. Ishigami (*) .K. Yoshimitsu . H. HondaDepartment of Clinical Radiology,Graduate School of Medical Sciences,Kyushu University,3-1-1 Maidashi,Higashi-ku, Fukuoka, 812-8582, Japane-mail: Ishigamikousei@aol.comTel.: +81-92-6425695Fax: +81-92-6425708

S. AmadaDepartment of Obstetrics andGynecology,Graduate School of Medical Sciences,Kyushu University,3-1-1 Maidashi,Higashi-ku, Fukuoka, 812-8582, Japan

Fig. 1 A 37-year-old woman with recurrent ovarian cancer. a CTdemonstrated a high-density lobulated mass between the psoas andiliacus muscle (arrow). Dense calcifications are noted within thetumor. b Coronal T2-weighted MR imaging (TR/TE=3,690/91 ms)shows the mass to be hyperintense relative to skeletal muscles. Notethe anatomical location of the mass, which corresponds to theterritory between the right iliolumbar and fourth lumbar vessels

Sir,A 37-year-old woman complained of a1-year history of right-sided lowerback pain and right lower-extremityswelling. She had undergone rightoophorectomy, without lymphadenec-tomy, for low-grade ovarian cancer 15years previously at an outside institu-tion, but she was lost tofollow-up. CT demonstrated a high-density retroperitoneal tumor betweenthe right psoas and iliacus muscles.Dense calcifications were noted withinthe tumor (Fig. 1a). MR imagingdemonstrated the tumor to be isoin-tense on T1-weighted images andhighly intense on T2-weighted images(Fig. 1b) relative to the skeletal mus-cles. Gadolinium-enhanced T1-weighted images showed homogenouscontrast enhancement. The radiologi-cal differential diagnoses includedprimary retroperitoneal sarcoma andrecurrent ovarian cancer, although 15years had passed since her previouscurative surgery for ovarian cancer.

Surgical resection and reconstruc-tion of the right iliac arterial graft wereperformed. Microscopic metastases inthe left external iliac, right commoniliac, and paraaortic lymph nodes werefound. In addition, the peritoneal fluid

was found to be positive for cancercells. The specimen of the retroperi-toneal tumor represented serous pa-pillary adenocarcinoma with abundantpsammoma bodies. The diagnosis ofrecurrent ovarian cancer was rendered.Dense calcification and high-densitysurrounding tissue of the tumor rep-resented psammoma calcifications ofovarian cancer.

Our case did not fit typical lym-phatic pathways from ovarian cancer.Because of the characteristic location,our case was consistent with rightposterior iliac crest lymph node me-tastasis. The iliolumbar and deep cir-cumflex iliac vessels run through thespace between the iliacus and psosasmuscles. Castellino [1] has reported agroup of lymph nodes adjacent to theposterior iliac crest, presumably re-lated to the iliolumbar or deep cir-cumflex iliac vessels. Park et al. [2]have called this nodal group posterioriliac crest nodes. The involvement ofposterior iliac crest nodes can beobserved in patients with malignantlymphoma [1] and pelvic tumors,more frequently in those with prostatecancer than in those with testicular andovarian cancers [2]. In addition, Konet al. [3] have described lymph node

metastases between the psoas muscleand lumbar spines in patients withuterine cervical cancers, causing de-struction of the lumbar vertebral body.Kon et al. [3] have also suggested alymphatic pathway from the posterioriliac crest nodes to the paraaorticlymph nodes along the lumbar vesselsby demonstrating an anastomosingbranch between the iliolumbar and thefourth lumbar arteries on angiography.Therefore, the posterior iliac crestnode is an unusual metastatic pathwayfrom pelvic malignancies toward theparaaortic lymph nodes, either aslymphatic collateral when the com-mon iliac lymph nodes are obstructed[2] or as a variation in lymphaticdrainage [1]. In our case, surgicalintervention or microscopic iliaclymph nodes metastases might havealtered the lymphatic pathway.

We have presented a case of ovariancancer that recurred 15 years later. Wewould like to emphasize that oneshould be aware of an unusual lym-phatic pathway from pelvic malignan-cies to the posterior iliac crest node. Inaddition, low grade ovarian cancermay recur more than 10 years later.

References

1. Castellino RA (1990) Lymph nodes ofthe posterior iliac crest: CT and lym-phographic observations. Radiology175:687-689

2. Park JM, Charnsangavej C, YoshimitsuK, Herron DH, Robinson TJ, Wallace S(1994) Pathways of nodal metastasisfrom pelvic tumors: CT demonstration.Radiographics 14:1309-1321

3. Kon Y, Saida Y, Kurosaki Yet al (1990)Psoas lymph node metastasis in patientswith carcinoma of the uterine cervix(article in Japanese). Nippon IgakuHoshasen Gakkai Zasshi 50:1237-1242

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