Diagnosis of tubo-ovarian filariasis with retroperitoneal extension: A radiological challenge

A 20-year-old female patient presented with chief complaints of low-grade fever and whitish cloudy urine. There was no history of loin pain, dysuria, increased frequency of urination, swelling of feet, facial puffiness, or bleeding manifestations. She was averagely built and nourished. There was no lymphadenopathy or pedal edema. Investigations revealed hemoglobin of 13.6 gm%, total leucocyte count of 7400/mm 3 , neutrophils 31%, lymphocytes 22%, and marked eosinophilia 43%. Urine examination showed no casts, dysmorphic red blood cells, white blood cells, or malignant cells. Urine triglyceride was 200 mg/dL suggestive of chyluria. Twenty-four-hour urinary protein was within normal limits. Urine culture was sterile. Ultrasonography of abdomen showed complex multiloculated cystic lesions in bilateral adenexal mass along with an incidental finding of a left-sided dermoid cyst. The cystic lesions showed the characteristic “dancing larvae sign” [ Figure 1 ]. Transabdominal ultrasound of the abdomen showing the uterus with bilateral adenexal irregular shaped cystic lesions with dancing larvae within the lesions Contrast-enhanced computerized tomography (CT) showed rind of nonenhancing, cystic lesions around the aorta, inferior vena cava, renal artery, and proximal iliac vessels likely representing dilated lymphatic channels [ Figure 2 ]. Axial section of contrast-enhanced computerized tomography of the abdomen showed hypodense nonenhancing lesions in the retroperitoneum encasing the aorta, the inferior vena cava, and renal vessels A large, nonenhancing, complex cystic pelvic mass was seen involving bilateral adenexal mass and a dermoid cyst on the left side [Figures 3 and 4 ]. Axial section of contrast-enhanced computerized tomography of the pelvis showing lobulated nonenhancing cystic lesions involving bilateral adenexal mass Axial section of contrast-enhanced computerized tomography of the pelvis showing hypodense lobulated cystic lesions along with a dermoid cyst on the left side The mass was encasing the ureters. However, there was no hydronephrosis. The aorta and the inferior vena-cava were encased without luminal compromise. In view of the chyluria and classical microfilarial dance on cine sonography, a radiological diagnosis of bilateral tubo-ovarian filariasis with retroperitoneal extension was made. The patient was started on tab diethylcarbamazine for 21 days. The patient responded well, became asymptomatic, and chyluria ceased. The pelvic lesions had reduced to one-third of its size and no larval dance was seen on repeat ultrasound. The patient was posted for surgery and pathological analysis showed irregular filarial larval structures surrounded by dense inflammation suggestive of bilateral tubo-ovarian filariasis along with a left-sided dermoid cyst.

Lymphatic filariasis is caused by infections with Wuchereria bancrofti, Brugia malayi , or Brugia timori .[ 1 ] The most common presentation of the disease is hydrocele which is followed by lymphedema of lower limbs leading to elephantiasis.[ 1 ] Although the laboratory diagnosis of filariasis has conventionally been made by demonstrating microfilariae in peripheral blood smear, there have been reports where diagnosis was made by finding microfilariae in material obtained by aspiration of various organs including thyroid, soft tissue, bone marrow, epididymis, lungs, breast, gastric brushing, hydrocele fluid, and retroperitoneal cyst.[ 2 3 4 5 ]

Lymphatic filariasis presenting as bilateral tubo-ovarian masses with retroperitoneal extension is very rare. Ultrasonography and CT scan helped us to differentiate it from other complex multiloculated cystic lesions of pelvis. Cine ultrasound demonstrating “dancing larvae sign” is pathognomonic of filariasis. Although filariasis is very common in India presenting as lymphedema and hydrocele, it has also got rare manifestations like pelvic and retroperitoneal cystic masses. Hence, it should also be considered in the differential diagnosis of pelvic cystic lesions in family healthcare practice. Written consent was obtained from the patient to publish this case report. Nil. There are no conflicts of interest.

Lymphatic filariasis has varied presentations and the worm has been recovered from several atypical tissues.[ 2 3 4 5 ] The adult worms live in the lymphatics throughout the body and cause blockage of lymphatics leading to extensive lymphangiectasia and lymphedema. Retroperitoneal filariasis is rare even in endemic regions.[ 6 ] Obstructed lymphatic vessels, rupture of lymphatics causing extravasation of chyle, and the presence of ectopic lymphatic tissue have been propounded as the possible etiologies.[ 7 ] Mehta et al. reported a filarial abscess in their study of retroperitoneal tumorous lesions.[ 8 ] Gupta et al. diagnosed an infected retroperitoneal cyst to be of filarial origin by aspiration cytology and treated it surgically.[ 9 ] Kapoor et al. reported a cystic lesion in the retroperitoneum extending from the subhepatic region to the pelvis and causing compression of the inferior vena cava.[ 6 ] Ahn et al. published the CT and magnetic resonance imaging findings of a dilated thoracic duct and diffuse retroperitoneal lymphangiectasis because of Bancroftian filariasis .[ 10 ] Patients with retroperitoneal filarial lymphangiectasis usually present with abdominal pain and fever.[ 7 8 ] The treatment remains a course of antifilarial drugs and most of these lesions have significant regression. The role of surgery seems to be very limited in the absence of secondary infection.