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Splenogonadal fusion associated with cryptorchidism

Alexander Cho¹, Musa Kaleem², Supul Hennayake¹
¹Department of Paediatric Urology
²Department of Paediatric Radiology
Royal Manchester Children’s Hospital, Manchester, United Kingdom

 

Correspondence

Mr Alexander Cho
Royal Manchester Children’s Hospital
Oxford Road
Manchester, M13 9WL
United Kingdom
Tel: 07930-507-556
Work: 01603-286-286 bleep 1041
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Abstract

Spleno-gonadal fusion is a rare congenital anomaly characterised by abnormal fusion of splenic tissue to a gonad. There have been approximately 150 cases described in literature since initial descriptions in 1889 by Dr Pommer. In this case report, we describe a patient with a continuous type of spleno-gonadal fusion and cryptorchidism in whom different radiological modalities were used to establish this diagnosis. Awareness of this condition and the use of appropriate investigations may prevent unnecessary orchidectomy.

 

Case Report

A 7 year old boy was admitted for assessment of bilateral impalpable testes. Clinical examination revealed bilateral impalpable testes but no intra-abdominal masses. Previous history included staged surgery for correction of major hypospadias, pulmonary tuberculosis and asthma.

Pre-operative endocrine investigations were normal including adrenal function, with normal responses to gonadotrophin releasing hormone and human chorionic gonadotrophin stimulation testing. Blood tests showed no 5-alpha reductase deficiency with normal renal function and full blood count. Genetic testing revealed 46XY karyotype, with no mutation detected for androgen insensitivity syndrome.

A pre-operative abdominal ultrasound and MRI scans failed to detect any testicular tissue in the groin, pelvis or abdomen.

He underwent an explorative laparoscopy where the right testicle was found in the pelvic cavity with well-developed vasal blood vessels making it suitable for a stage-one Fowler-Stevens procedure. A structure similar in appearance and size to a testis was found much higher in the left para-colic gutter, the cephalic aspect of which seemed to expand in to a reddish-brown solid lesion about 4-5cm in diameter (fig 1).

7.1.4

Figure 1: Laparoscopic intra-operative picture shows a soft tissue mass cephalad to the ectopic left testis (asterisk)

The immediate concern was malignant transformation of the intra-abdominal testis, but as the capsule of the lesion appeared intact with no invasion into surrounding tissues, it was decided to perform further investigations prior to radical surgery.

Subsequent investigations including tumour markers such as lactate dehydrogenase, alpha- feto-protein and beta-human chorionic gonadotrophin were within normal limits. Further imaging with an abdominal CT scan demonstrated a 2.8 x 2.6 x 6cm enhancing soft tissue mass in the left flank lateral to the psoas muscle with blood supply arising from the left renal capsule and splenic hilum (fig 2a). Enhancement pattern of this mass was similar to the spleen and consistent with a splenule. Left testis could not be well visualised on CT. There was a second smaller splenule identified superiorly adjacent to the tip of the spleen. Both splenules and spleen showed partial continuity on contiguous slices in keeping with a continuous type of. In addition a segment of the right lower lung lobe showed abnormal drainage of the pulmonary venous system into the inferior vena cava, in keeping with partial anomalous pulmonary venous drainage (PAPVD).

A repeat abdominal ultrasound concurred with CT findings by demonstrating a typical spleen like echo-texture of the left flank splenule (fig 2b). Left testis was again inconspicuous on ultrasound. Review of the previously performed MRI scan also corroborated well with the CT and ultrasound findings of two splenules, and confirmed the fusion of the ectopic left testis with the inferior splenule (fig 3).

7.1.6 7.1.5

Figure 2A: Contrast enhanced axial CT Scan at the level of iliac crest shows the left para-psoas inferior splenule (arrow) with a spleen like enhancement

Figure 2B: Sonogram of the inferior splenule demonstrating a spleen like echotexture

7.1.7 

Figure 3: MRI Coronal STIR image shows the relationship between spleen, two splenules (arrows) and the left ectopic testis (blocked arrow) fused with the inferior splenule

The diagnosis was further supported by a Technetium (Tc99m) labelled heat denatured red blood cell (RBC) scan. It demonstrated activity within the spleen and a trail of activity extending from the inferior splenic pole into the left iliac fossa to the known positions of the two splenules supporting the diagnosis of a continuous splenogonadal fusion (fig 4). As the possibility of testicular tumour was excluded, the planned urgent exploration with a view to radical left orchidectomy was cancelled. The current plan is a two-stage Fowler-Stevens procedure for the right testicle and surgery on the left testis subsequently. The patient has also been referred to a cardiologist in view of PAPVD.

7.1.8

Figure 4: Tc99m labelled heat-denatured RBC scan demonstrates radio-isotope uptake in the spleen (asterisk) which is continuous inferiorly with the two splenules (arrows)

Discussion

Ultrasound of the groin and pelvis is the first line investigation for cryptorchidism followed by MRI for abdominal localisation. Laparoscopy is also a well established technique to explore retro-peritoneum with an additional potential therapeutic role.

Splenogonadal fusion (SGF) is a rare congenital anomaly associated with cryptorchidism. It affects both sexes with a male predominance (16:1).

The aetiology is unclear, but it is proposed that an insult during the 5th to 8th weeks of the embryological life, when the developing spleen is in intimate contact with the mesonephric-gonadal anlage, results in fusion between the two surfaces resulting in mass consisting of splenic and gonadal tissue [1]. However, the presence of splenogonadal fusion interferes with normal gonadal descent as descent of the gonad may also cause descent of part of the spleen. As a result, this condition is commonly associated with undescended testis or inguinal hernia.

Two subtypes of SGF have been described [2]. The continuous type describes the gonad attaching directly to the orthotopic spleen. It frequently contains a vascular packet originating from the spermatic or ovarian vessels. Associated anomalies are more common in the continuous type and include orofacial, limb, cardiac and lung abnormalities. The discontinuous type consists of gonadal fusion with ectopic splenic tissue, without an evident connection to the orthotopic spleen. Associated anomalies are rare in this subgroup.

In many cases, the accessory spleen attached to the testicle is found intra-operatively and mistaken for malignancy, leading to un-necessary orchidectomy. Awareness of this entity is the most important factor in appropriate management. Relevant investigations include Tc-99m sulfur colloid imaging, which would show uptake in both the spleen and accessory splenic tissue, is recommended as the best diagnostic test [3]. This test was not available to us, but the heat-damaged red cell labelled scan was equally useful in making the diagnosis. While awareness of this condition may reduce rate of unnecessary orchidectomy, there have been case reports of simultaneous spleno-gonadal fusion and malignant testicular tumour [4, 5]. Presence of tumour is not excluded by presence of spleno- gonadal fusion and appropriate investigations must be carried out.

Conclusion

This case report highlights that awareness of spleno-gonadal fusion may prevent un-necessary orchidectomy in these patients. If necessary, the affected testicle can be separated from the splenic tissue with satisfactory results, thereby maximising the chances of fertility for the patient [6].

Tc99m labelled Heat-denatured RBC scan can provide useful supporting evidence in combination with other radiological modalities and haematological tumour markers to confirm this diagnosis.

Acknowledgement

Karen Parkinson, Superintendent Radiographer, Nuclear Medicine Department, Royal Manchester Children’s Hospital.

 

 

References

1. Varma DR, Sirineni GR, Rao MV, et al: Sonographic and CT features of splenogonadal fusion. Pediatric Radiology 2007;37:916-919.

2. Putschar WG, Manion WC: Splenic-gonadal fusion. Am J Path 1956;32:15-35.

3. Steinmetz AP, Rappaport A, Nikolov G, et al: Splenogonadal fusion diagnosed by spleen scintigraphy. J Nucl Med 1997;38:1153- 1155.

4. Imperial SL, Sindhu JS: Nonseminomatous germ cell tumor arising in splenogonadal fusion. Arch Pathol Lab Med 2002;126:1222–1225.

5. Thomsen BM, Wierod FS, Rasmussen KC: Combined malignant testicular tumor and splenogonadal fusion. A case story. Scand J Urol Nephrol 1997;31:393-5.

6. Jequier S, Hanquinet J, Lironi A: Splenogonal fusion. Pediatr Radiol 1998;28:526.