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Keywords:

  • 3D ultrasound;
  • gynecological cancer;
  • lymphocyst;
  • pelvic lymphadenectomy

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Objectives

To determine, in patients who have undergone bilateral pelvic lymphadenectomy for gynecological cancer, the incidence of lymphocyst formation, their change in size with time, risk factors and correlation with symptoms.

Methods

This was a prospective observational study of 108 patients undergoing bilateral pelvic lymphadenectomy for gynecological cancer in our unit. We performed serial three-dimensional (3D) ultrasound assessment at 2 and 6 weeks and 3, 6, 9 and 12 months after surgery. Before each ultrasound assessment, symptoms were recorded and a physical examination was performed.

Results

Forty-eight (44.4%) patients had unilateral or bilateral lymphocysts detected during the follow-up period; 26 were on the left side, 16 were on the right side and six were bilateral. In 39 (81.2%) of the patients, the lymphocysts were first noted 2 weeks after the operation. In nine (18.8%) the lymphocysts persisted until 12 months after surgery. There was no association between lymphocyst formation and diagnosis, type of operation performed, surgeon, operative blood loss, adjuvant radiotherapy and number of lymph nodes removed. Four lymphocysts were detected by physical examination before the ultrasound diagnosis. There was no association between lymphocyst and symptoms, including pain over the abdomen, pelvis, thigh, legs or back, lymphedema, fever or symptoms of cystitis. Only one patient developed an infection of the lymphocyst, which required surgical intervention.

Conclusion

Lymphocyst formation is common following bilateral pelvic lymphadenectomy. Most patients with lymphocysts are asymptomatic and the development of major complications is rare. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

Pelvic lymphocyst was first reported in the 1950s as a complication of surgery1, 2, yet the exact mechanism for pelvic cyst formation following lymphadenectomy is still unclear. The reported incidence of lymphocyst following surgery ranges from 1 to 49%3–6, with figures based on palpation alone in some studies4, 5. Computed tomography was used in one of the studies6 and the incidence of lymphocyst formation in cervical cancer patients treated with radical surgery was found to be 20%.

Lymphocysts have generally been detected within the first 8 weeks after surgery7–9. Such early detection may be because imaging studies were sometimes performed for common postoperative symptoms such as lower abdominal pain, pelvic pain and lower back pain, and lymphocysts were detected during the examination although they may not have been the cause of the symptoms. Otherwise, most of the lymphocysts would have gone undetected.

Lymphocysts of significant size may lead to symptoms resulting from compression on the surrounding structures. If lymphocyst is diagnosed and symptoms are significant, treatment may be offered. Some centers have reported their experience in managing symptomatic and asymptomatic lymphocysts using needle aspiration, percutaneous catheter drainage or sclerotherapy3, 10, 11. Whether treatment for asymptomatic patients is required remains controversial.

This study used 3D ultrasound to determine: (1) the incidence of lymphocyst formation following bilateral pelvic lymphadenectomy; (2) the time of appearance of lymphocysts and their change in size with time; (3) associated symptoms or complications with respect to the size of the lymphocysts. 3D ultrasound was used because with this technique volume can be estimated for both spherical and non-spherical structures.

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

This was a prospective study conducted from October 2003 to November 2004 at the Department of Obstetrics and Gynaecology of the University of Hong Kong. Patients undergoing bilateral pelvic lymphadenectomy in our unit for gynecological cancers were recruited. We excluded patients also undergoing para-aortic lymphadenectomy. Patients were informed of the purpose of and procedures involved in the study and gave their written consent to participate before recruitment. The study was approved by the institutional review board of the hospital.

The demographic data of the study population were recorded. Before each ultrasound examination, patients were asked about symptoms, including pelvic pain, lower abdominal pain, thigh pain, leg pain, back pain, lymphedema, abdominal distension and fever, using a checklist. The Visual Analog Scale (VAS) was used to assess pain intensity. Patients also underwent bimanual pelvic examination before sonography.

All transabdominal 3D ultrasound examinations were performed by one of two operators (K.F.T. and K.W.L.) using a Voluson 730® (GE Healthcare, Zipf, Austria) ultrasound machine. Patients were asked to empty their bladder before the examination. The ultrasound machine settings were as follows: frequency, mild; dynamic set, 2; balance, G > 140; smooth, 5/5; ensemble, 12; line density, 7; power Doppler map, 5. Power Doppler mode settings included: gain, − 6.0; balance, 140; quality, normal; wall motion filter, low 1; velocity range, 0.9 kHz. Lymphocysts were diagnosed when sonography revealed a thin-walled anechoic pelvic ‘cyst’ without intracystic septation or echogenic tissues and situated in close proximity to the iliac vessels12. Power Doppler was used to assess the proximity of the anechoic pelvic cyst to the iliac vessels. If lymphocysts were detected, their volume was measured using the ultrasound machine's VOCAL® (Virtual Organ Computer-aided AnaLysis) mode. During analysis, the manual mode of the VOCAL contour editor was used to cover the entire 3D volume of the lymphocyst, with a 30° rotation step. This assessment was first performed 2 weeks after surgery and was then repeated at 6 weeks and 3, 6, 9 and 12 months after the operation. If no lymphocysts were detected, ultrasound assessment was stopped at 6 months. Example ultrasound images are shown in Figure 1.

thumbnail image

Figure 1. Imaging of lymphocysts which developed in patients following bilateral pelvic lymphadenectomy. (a) Two-dimensional (2D) ultrasound; (b) 2D ultrasound with power Doppler (transverse section) showing the external iliac artery at the surface of the lymphocyst; (c) three-dimensional (3D) ultrasound showing the lymphocyst in different planes; (d) 3D ultrasound with volume estimation using VOCAL (Virtual Organ Computer-aided AnaLysis).

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Statistical analysis was performed using SPSS version 11.5 (SPSS Inc., Chicago, IL, USA). To determine the association between lymphocyst formation and the patient symptoms, diagnosis of the primary tumor, type of operation performed, adjuvant therapy used and surgeons who performed the operation, the chi-square test and Fisher's exact test were used. The Mann–Whitney U-test was used to determine the association between lymphocyst formation and operative blood loss and the number of lymph nodes removed. P < 0.05 was considered statistically significant.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

One hundred and ten patients were recruited from October 2003 to September 2004 and 108 of them completed the study. Among them, 35 had carcinoma of the cervix, 41 had carcinoma of the endometrium, 25 had ovarian malignancies, one had carcinoma of the vagina, five had double primary carcinoma of the ovary and endometrium and one had double primary carcinoma of the Fallopian tube and endometrium. The operations performed were: total abdominal hysterectomy and bilateral pelvic lymphadenectomy with or without omentectomy in 59 (55%) cases; Wertheim's hysterectomy with or without bilateral salpingo-oophorectomy in 38 (35%) cases; laparoscopy-assisted vaginal hysterectomy and laparoscopic bilateral pelvic lymphadenectomy in seven (6%) cases; unilateral salpingo-oophorectomy and bilateral pelvic lymphadenectomy with omentectomy in two (2%) cases; bilateral pelvic lymphadenectomy in one (1%) case; and radical vaginectomy in one (1%) case. Ninety-six patients had operations performed by one of four surgeons within the gynecological oncology team in our unit. Visiting surgeons performed the rest of the operations. There was no significant difference between the median number of lymph nodes removed from the left and right sides (15 (range, 5–35) vs. 14 (range, 5–33)). None of the patients received prophylactic anticoagulation or had pelvic drainage following the operation. The peritoneum was not closed in any of the patients.

Forty-eight (44%) of the 108 patients had lymphocysts detected during the follow-up period. The incidence of lymphocysts was highest, and most of them had first appeared, by 2 weeks postoperatively (Table 1, Figure 2). Lymphocysts appeared slightly more frequently on the left side, but not significantly so. Nine patients had persistent lymphocysts at the 12-month follow-up. Table 2 shows the median volumes of lymphocysts present at different examinations following surgery. Comparing median volumes overall, there was no significant reduction in size over time. Fourteen patients had lymphocysts first appearing 2 weeks postoperatively and persisting until 6 months; analysis of cyst volumes in this group showed a reduction in size over time, with the median volume decreasing from 11.1 mL at 2 weeks to 6.4 mL at 6 months.

thumbnail image

Figure 2. Change in the incidence of lymphocysts with time in 108 patients following bilateral pelvic lymphadenectomy. Lymphocysts were first detected 2 weeks (□), 6 weeks (equation image) or 6 months (equation image) following surgery.

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Table 1. Time at which lymphocysts were first detected in 48 patients following bilateral pelvic lymphadenectomy
Time after surgeryn (%)Laterality at first appearance (left/right/bilateral)
2 weeks39 (81.2)20/13/6
6 weeks7 (14.6)5/2/0
3 months0
6 months2 (4.2)1/1/0
9 months0
12 months0
Table 2. Volume of lymphocysts in 48 patients at different time intervals following bilateral pelvic lymphadenectomy
Time after surgeryVolume of lymphocysts (mL, median (range))
Left sideRight side
  • *

    One patient only.

2 weeks11.1 (1.0–71.5)5.3 (0.8–103.1)
6 weeks11.7 (0.5–189.4)3.3 (0.7–39.5)
3 months7.5 (1.0–57.6)6.6 (1.6–43.4)
6 months6.3 (0.8–159.3)1.2 (0.4–42.4)
9 months6.4 (1.0–44.7)21.9 (2.1–41.7)
12 months4.5 (1.0–32.5)5.9*

There was no association between lymphocyst formation and the patient symptoms (Table 3), diagnosis, surgeon who performed the operation, type of operation, operative blood loss, adjuvant therapy including radiotherapy, or number of lymph nodes removed (left and right sides were analyzed separately). Four patients had lymphocysts detected by physical examination before sonography; the volumes of these lymphocysts were 6.5, 12.4, 41.0 and 189.4 mL at the time of detection. In one other case, a lymphocyst was detected on physical examination, but this was confirmed to be a false-positive case on ultrasound examination. One patient developed infection of a right-sided lymphocyst and drainage was performed by laparotomy.

Table 3. Symptoms experienced by 108 patients following bilateral pelvic lymphadenectomy, 48 of whom developed lymphocysts
Time after surgeryNumber of patients (overall (with lymphocysts))
Lower abdominal/ pelvic painLower limb edemaBack painLeg painThigh painAbdominal distension
  • *

    Chi-square test: no significant difference.

  • Fisher's exact test: no significant difference.

2 weeks14 (6)*0 (0)0 (0)0 (0)0 (0)2 (1)
6 weeks10 (6)1 (0)1 (0)0 (0)0 (0)0 (0)
3 months4 (3)1 (0)0 (0)0 (0)0 (0)0 (0)
6 months5 (4)2 (0)0 (0)2 (0)0 (0)0 (0)
9 months0 (0)0 (0)0 (0)1 (0)1 (0)0 (0)
12 months0 (0)0 (0)0 (0)0 (0)0 (0)0 (0)

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References

We found that the incidence of lymphocyst formation following bilateral pelvic lymphadenectomy for gynecological malignancies was 44.4%, which is comparable to the highest reported incidence of 49%3. The high incidence that we observed was probably due to the serial ultrasound examinations being performed over short time intervals, which increased the chance of detecting the lymphocysts. Previous studies found that most lymphocysts appeared 3–8 weeks after sugery8, 9. We found that about 80% of the lymphocysts had appeared by 2 weeks and 96% had appeared by 6 weeks after surgery.

Lymphocysts are not uncommon findings if imaging studies for abdominal or pelvic pain are performed after pelvic lymphadenectomy. Symptoms are usually attributed to lymphocysts if they are present. In this study, we did not find a correlation between the presence of lymphocysts and a list of symptoms (Table 3) which may be caused by a space-occupying lesion inside the pelvis. The most common complaints we recorded were abdominal and pelvic pain; among the 14 patients complaining of these symptoms, only six had lymphocysts. The other 41 patients who had lymphocysts did not complain of any symptoms, except one with abdominal distension. In all patients who complained of abdominal and pelvic pain, the symptoms had subsided by 9 months. Of all the patients with lymphocysts, only one developed infection, and intervention was required.

Our use of serial ultrasound examinations showed that most of the lymphocysts resolved spontaneously with time and in individual patients we noted a general trend of reduction in size of the lymphocysts over time. Of the 39 patients who had lymphocysts that were first noted 2 weeks after surgery, in only 14 (36%) did the cysts persist until 6 months and in seven (18%) the cysts persisted until 12 months following surgery.

There have been advocates for the treatment of pelvic lymphocysts using needle aspiration, percutaneous catheter drainage and sclerotherapy3, 10, 11. While these methods were shown to be useful in treating the lymphocysts, some of the patients developed complications such as secondary infection. We have shown that most such lymphocysts are asymptomatic and resolve spontaneously with time. Therefore, ultrasound examination for lymphocysts should be limited to those having symptoms and treatment should be applied only to those with complications of the lymphocysts, i.e. those with significant symptoms or morbidity such as infection.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. References