The "filarial dance" is not characteristic of filariasis: observations of "dancing megasperm" on high-resolution sonography in patients from nonendemic areas mimicking the filarial dance and a proposed mechanism for this phenomenon

The Rare, the Odd, and the Atypical: A Pictorial Essay of Testicular and Paratesticular Diseases

ABSTRACT

Understanding a variety of scrotal diseases is essential to developing an accurate differential diagnosis and is critical in providing optimal patient care. Ultrasound is the imaging modality of choice when evaluating for scrotal pathology, with the major purpose of locating such pathology to either the testis, or epididymis, or other intrascrotal structures, as well as characterizing lesions as solid or cystic. It is generally assumed that most solid intratesticular masses are more likely malignant, whereas most extratesticular ones are benign, although some exceptions to that rule exist. This pictorial essay will focus on rare and less commonly encountered benign and malignant testicular and paratesticular pathologies, which may pose a diagnostic dilemma for interpreting radiologists and treating physicians. Knowledge of their imaging characteristics will help narrow the differential diagnosis and assist in proper patient management and care.

Case Report: Filaria or Megasperm? A Cause of an Ultrasonographic "Filarial Dance Sign"

Bancroftian filariasis can cause genital abnormalities related to chronic inflammation and obstruction of the afferent lymphatic vessels, and may demonstrate a "filarial dance sign" on scrotal ultrasound with mobile echogenic particles observed. We present a patient with a positive "filarial dance sign," travel within Latin America, and negative filarial serology.

Sonography of Scrotal Wall Lesions and Correlation With Other Modalities

The scrotal wall may be involved in a variety of pathologic processes. Such lesions may rise primarily from the layers of the scrotum or may be due to a process arising from scrotal content. Imaging is not needed in most cases, but it may be useful for making such differentiations and for evaluation of possible involvement of the testes and epididymides in cases of primary wall abnormalities. This pictorial essay will show the imaging findings observed in a variety of pathologic conditions affecting the scrotal wall, both common and unusual ones, with an emphasis on clinically relevant findings and features that lead to a specific diagnosis.

"Filarial dance sign" real-time ultrasound diagnosis of filarial oophoritis

Filariasis is a parasitic disease caused by Filarial nematodes (Wuchereria bancrofti, Brugia malayi, and Brugia timori) that commonly causes lymphatic obstruction resulting in edema and increase in the size of the affected organ. Filariasis is diagnosed by identifying microfilariae on Giemsa stain. The immunochromatographic card test is diagnostic. Ultrasound is the imaging modality of choice for detecting adult filarial worms/microfilaria in the lymphatic system, which are responsible for the classic "filarial dance sign" caused by twirling movements of the microfilariae. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:500-501, 2016.

Who Is Doing the Dance in Epididymis: The Principle of Moblile Echogenicities Without Filarial Infection: Case Report

The aim of this study was to explore the principle of moblile echogenicities in epididymis in patients with a history of postvasectomy or infertility, which were reported as the characteristic sonographic sign of filarial infection.We reported a 38-year-old man presented with a 3-year history of infertility after marriage. Ultrasound imaging revealed an enlarged body in the inner left epididymis along with innumerable punctate mobile echogenicities, which showed random to-and-fro movements in the left epididymis. This had previously been recognized as the sonographic filarial dance sign of live filarial worms or microfilaria. The patient subsequently underwent needle aspiration of the left epididymis.Histopathological examination confirmed that the mobile echogenicities were a large number of macrophages with phagocytized sperm or clumps of agglutinated sperm. Our report includes a video clip that will help familiarize readers with this phenomenon.Our case highlighted that moblile echogenicities should be an important sign for epididymal obstruction to initiate corresponding treatment.

Sonographic Evaluation of Mobile Echogenicities Within the Epididymis

Current ultrasound systems have significantly improved spatial and temporal resolution secondary to increased transducer frequencies, increased bandwidth, and complex signal processing such as harmonics and compound scanning. The case presented describes the differential diagnoses of small, linear, mobile echogenic foci visualized by sonography in the left epididymal tail. Differentiation of moving parasites associated with filariasis versus mobile sperm may become more difficult as the resolution of ultrasound equipment continues to improve.

A rare case of ovarian and pelvic filariasis

Lymphatic filariasis is an important tropic disease associated with significant morbidity. The patients in endemic areas mostly experience problems related to lymphatic obstruction. Physicians practicing in non- endemic areas rarely consider filariasis, especially if it is an uncommon presentation. We present a young woman who posed a significant problem in the diagnosis of ovarian filariasis.

The filarial dance sign in scrotal filarial infection: a case report

We describe a case of the filarial dance sign (FDS) in the epididymal region of a 22-year-old migrant worker from India who presented with a tender right scrotal swelling. Sonographic examination revealed multiple cystic lesions in the paratesticular region. The FDS was visualized within one of the cystic lesions. FDS is diagnostic of lymphatic filariasis in the appropriate clinical context.

Mobile echogenicities on scrotal sonography: is the finding associated with vasectomy?

OBJECTIVES

The purpose of this study was to determine whether mobile echogenicities seen in the epididymis on scrotal sonography are associated with prior vasectomy.

METHODS

We prospectively obtained a sonographic video clip of each epididymal body in outpatients sent for scrotal sonography. The presence of punctate mobile echogenicities in the epididymal body was noted, and the indication for the sonogram, patient age, and history of vasectomy were recorded. This study was compliant with the Health Insurance Portability and Accountability Act and was approved by the Institutional Review Board.

RESULTS

Of 345 patients (mean age, 44.9 years), 56 (16.2%) had undergone vasectomy and 289 had not. Mobile echogenicities were found in 8 patients, 7 of whom were postvasectomy. The rates of mobile echogenicities appearing were 12.5% (7 of 56) in the vasectomy group and 0.3% (1 of 289) in the nonvasectomy group (P < .0001, Fisher exact test). Epididymal cysts were seen in 184 of 345 patients (53.3%). There was no significant difference in the presence of epididymal cysts in the patients who had undergone vasectomy compared to those who had not (P = .34), including 30 of 56 postvasectomy patients (53.6%) and 154 of 289 patients without vasectomy (53.3%). Pain was reported by 177 patients (51.3%), including 34 of 56 (60.7%) in the postvasectomy group and 143 of 289 (49.5%) without vasectomy. The presence of pain was similar in both groups (P = .15).

CONCLUSIONS

The presence of mobile echogenicities in the epididymis is almost always a postvasectomy finding and occurs in approximately 12.5% of such patients. There is no significant difference in the rate of epididymal cysts or pain after vasectomy compared to those who have not had vasectomies.