Giant unilateral hydrocele "en-bisac" with right hydronephrosis in an adult: A rare entity.

Abdominoscrotal hydrocele consists of two large sacs; the abdominal and scrotal, both are connected via the inguinal canal. The diagnosis is made by clinical examination and can be confirmed with ultrasound scan. Surgical treatment is considered mandatory since spontaneous resolution is extremely rare. Herein, we report a case of giant unilateral hydrocele en-bisac who presented with spontaneous rupture of the sac.

INTRODUCTION

Abdominoscrotal hydrocele (ASH) is a rare entity, characterized by a large scrotal hydrocele that communicates in an hourglass fashion with an abdominal component through the inguinal canal.[1] ASH begins as a large scrotal hydrocele that subsequently expands into the inguinal canal and, finally, into the abdomen. We report a case of giant unilateral hydrocele en-bisac, occupying almost the entire abdomen and causing right hydronephrosis, who presented with spontaneous rupture of the sac.

CASE REPORT

A 24-year-old male presented with increasing swelling of the right scrotum and right lower abdomen for 1 year. Gradually, this swelling had involved the entire abdomen. He was evaluated elsewhere, with ultrasound abdomen followed by a computed tomography (CT) scan. The ultrasound of the abdomen revealed moderate to severe right hydronephrosis with gross free fluid in the abdomen. The CT scan revealed a large abdominal encysted collection (20.3 cm × 12.6 cm × 28 cm) that was communicating with the right scrotal sac (causing hydrocele) and leading to right hydronephrosis [Figure 1]. Three months later, the patient presented to us with a history of sudden and spontaneous disappearance of the abdominal lump and appearance of painless scrotal edema with minimal discomfort, if any. Abdominal examination was normal while the scrotum was nontender and edematous, with loss of scrotal skin folds. His kidney function tests were unremarkable. Magnetic resonance imaging revealed hydrocele en-bisac with extravasation of fluid in tissue planes and the right testis had upmigrated in the abdominal portion of the sac [Figure 2]. The patient underwent excision of the dumbbell-shaped sac, herniotomy, reposition and fixation of the right testis, and repair of the deep-inguinal ring through a right inguinoabdominal extraperitoneal approach. The postoperative period was uneventful. Repeat ultrasonography performed 4 weeks later showed regression of the right hydronephrosis with no other abnormal findings.

Figure 1

Axial computed tomography images showing abdominoscrotal hydrocele with right hydronephrosis (a) and both the testes (white arrow) in their normal intrascrotal position (b)

Figure 2

Magnetic resonance imaging (MRI) images – (a) coronal MRI shows the abdominal sac of abdominoscrotal hydrocele (ASH) occupying the whole of the abdominal cavity and right testis (white arrow) displaced into the abdominal cavity. (b) Sagittal MRI shows a pressure effect on the right kidney (hydronephrosis [large black arrow]). (c) Coronal MRI shows ASH with displaced intraabdominal right testis and normally placed left testis. (d) Extravasation of fluid in soft tissue planes seen as white on fat-suppressed T2-weighted image (small black arrows)

DISCUSSION

Dupytren first described ASH in 1834, terming this condition as “hydrocele en-bisac.”[2] In this condition, the scrotal hydrocele communicates via the inguinal canal with an intraabdominal fluid-filled cyst that may lie retro- or preperitoneally.[1] ASH is an unusual condition, with only 84 cases in adults and fewer than 20 cases in children reported till 1999, and this accounts for only 0.17% of all types of hydrocele.[3]

The exact mechanism explaining the phenomenon of ASH is not clear, but the processus-vaginalis should be patent (at least partially) for it to develop. The most acceptable explanation is that increased pressure in the scrotal area and overdistension of the scrotal hydrocele sac pushes the proximal end of the hydrocele sac along the inguinal canal with intraabdominal herniation. A one-way valve effect of the patent-processus-vaginalis may allow further redirection of the scrotal fluid to the abdomen.[1]

The diagnosis of ASH should be suspected on clinical examination if a lower-abdominal mass is palpable just above the inguinal ligament in combination with a vaginal hydrocele. Positive transillumination test and cross-fluctuation between the abdominal and the scrotal collections are the clinical hallmarks of ASH diagnosis. The communication can be confirmed radiologically with ultrasonography, CT or magnetic resonance imaging (MRI). Patients can present with a variety of complaints related to the enlarging abdominal component. Most commonly, ASH presents as a simple abdominoscrotal mass. It may also present with acute abdominal symptoms due to the partial torsion in ASH and, rarely, it may present as mesothelioma due to neoplastic changes in the mesothelial lining.[4] Rare complications are hydroureter/hydronephrosis, leg edema, testicular flattening (all due to the pressure effects on these structures) and malignant mesothelioma of tunica vaginalis associated with intraabdominal testis in an ASH.[34] Other reported complications in association with ASH are testicular torsion, effects on spermatogenesis, acute appendicitis, hemorrhage and malignant transformation.[5] The differential diagnoses include spermatic cord lymphangioma, giant hydronephrosis extending into the true pelvis, bladder diverticulum and pelvic neuroblastoma.[6]

This patient had spontaneous rupture with disappearance of the huge abdominal lump and appearance of painless scrotal edema. There was also simultaneous upmigration of the right testis (prerupture CT showed normally positioned testis vis-à-vis postrupture MRI). Although spontaneous rupture is rare in scrotal hydrocele, however, few case reports have been reported previously.[7] In our knowledge, spontaneous rupture of ASH and testicular upmigration has not been reported previously.