Splenogonadal Fusion - A Rare Anomaly.

Splenogonadal fusion (SGF) is a rare congenital anomaly. Less than 200 cases of SGF have been documented till date. We present a case of 14-year-old male patient with swelling in the left scrotum for 3 years. Left orchidectomy was done. Histopathology showed ectopic splenic tissue surrounding testicular parenchyma suggestive of SGF. This rare congenital malformation may occur due to the proximity of developing gonad and spleen, resulting in abnormal connection between them during gestation. SGF presents a diagnostic challenge preoperatively; however, recent imaging methods can aid with the diagnosis. SGF as a rare cause of testicular swelling should be kept in mind and evaluated to avoid unnecessary orchidectomy. Copyright:

INTRODUCTION

Splenogonadal fusion (SGF) is a rare congenital anomaly due to fusion between the spleen and a gonad or mesonephric derivatives. Less than 200 cases of SGF have been documented in the literature. It almost always presents on the left side in males. The diagnosis of this uncommon anomaly is difficult, particularly preoperatively. Certain patients with SGF have undergone unnecessary orchidectomy due to the presence of a testicular lump.[1] SGF is commonly associated with inguinal hernias and other congenital anomalies. We present a case of SGF and discuss its embryological aspects and clinical implications.

CASE REPORT

A 14-year-old male patient presented with a swelling in the left scrotum for 3 years. It was unnoticed till recently when there was a history of trauma. The patient gave no history of pain. On examination, there was left testicular swelling: 6 cm × 5 cm × 3 cm, oval, firm with no redness, and was nontender [Figure 1]. The swelling was free from overlying skin, and the transillumination test was negative. The spermatic cord structures, opposite testis, and penis were normal. There was no other organomegaly. On ultrasonography (USG), the left testis was enlarged and showed a mass with hemorrhage and central focal necrosis. Preoperative differential diagnoses of testicular tumor – benign or malignant and testicular hematoma or torsion testis were kept in mind. Tumor markers – serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (HCG) were normal. As the tumor markers were negative, testicular hematoma or torsion testis was considered; hence, a scrotal approach was planned. Intraoperative findings showed considerable congestion of testis. Left orchidectomy was done. On cut section, a dark reddish-brown mass was seen enveloping the testis which showed central areas of hemorrhage and necrosis. The mass was inseparable from the testis as shown in the diagrammatic representation [Figures 2 and 3]. The histopathology report showed the presence of splenic tissue with congestion and hemorrhage surrounded by a capsule. The splenic tissue was present around the testicular parenchyma, which showed focal necrosis. This confirmed SGF of the testis [Figure 4].

Figure 1

Clinical presentation of splenogonadal fusion as left testicular swelling

Figure 2

Intraoperative testicular swelling showing congestion

Figure 3

Diagrammatic representation of cut section of testicular swelling showing testis in the center enveloped by the reddish-brown (splenic) tissue

Figure 4

Histopathology of testicular swelling showing spleen on the lower left side and testicular tissue on the upper right side

DISCUSSION

SGF is a rare congenital anomaly; less than 200 cases of SGF have been documented till date. The genital system develops from the ridge of intermediate mesoderm along the posterior abdominal wall. The germ cells originate in the epiblast, migrate along the primitive streak to reach the endoderm of the yolk sac by the 3rd week and reach the gonadal ridges by the 6th week. At about the 5th week of intrauterine life, the spleen primordium develops within the dorsal mesogastrium in the form of multiple nodules which fuse later.[2] SGF most commonly occurs in males because male gonads are superficial and outside the body.[1] This rare congenital anomaly occurs due to the proximity of developing spleen and gonad-testis during early embryological development, which facilitates their fusion.

SGF is classified into two types – continuous or discontinuous types. In the continuous type of SGF, the gonad is attached to the spleen. The discontinuous type consists of gonadal fusion with an accessory spleen or ectopic splenic tissue. Although classified into two types clinically, there are no significant differences between the two types.

SGF is common in children and adolescents.[1] The number of cases reported in patients <10 years of age accounts for 50% of the total cases reported, whereas patients <20 years old account for 70%.[1]

Our case is an example of discontinuous SGF because there was no cord-like tissue connecting the testis with the spleen, which was in normal position. SGF is most commonly associated with cryptorchidism, unknown testicular mass, or presenting as an incarcerated inguinal hernia. In total, 31% of SGF patients are diagnosed with cryptorchidism or inguinal hernias, and in 59% of cases, the cryptorchidism is bilateral. In cases of continuous SGF, ~50% are accompanied by other congenital malformations.[1] The incidence rate for continuous SGF is higher than that of discontinuous SGF, and most cases are accompanied by limb defect syndrome. Approximately one-fifth of continuous SGF cases also have other major congenital defects such as limb hypoplasia, micrognathia, cardiac defects, palatal defects, and anal defects. Karaman and Gonzales [3] reported a case of both transverse testicular ectopia and SGF. In the present case, the SGF was of discontinuous type and not associated with hernia or any other congenital malformation.

SGF typically presents as an asymptomatic testicular mass and may also present as acute testicular pain and swelling due to trauma or infections of ectopic splenic tissue.[3] In our case, there was a history of trauma which led to the incidental finding of left scrotal swelling. On USG left testicular mass with central necrosis was seen. The mass surrounding the testis was congested and inseparable from the testis, and hence, orchidectomy was performed. The diagnosis of SGF before surgery is challenging as it can mimic testicular tumors. Tumor markers such as serum AFP and beta-HCG can help in such cases. In the present case, both were normal. The lack of awareness of the occurrence of fusion of the spleen with the gonad leads to misdiagnosis. In such cases of testicular swellings, the use of fine-needle aspiration cytology and its role in diagnosis are debatable. Imaging methods, including USG, computed tomography, magnetic resonance imaging, and 99TCm spleen scanning can be of help in the diagnosis of SGF.[14] The accurate diagnosis can be achieved with the use of recent modalities only if the clinician is aware of this congenital anomaly and SGF as a very rare cause of testicular swelling is kept in mind. If the diagnosis of SGF is made preoperatively, there will be clarity in deciding the mode of treatment. Sometimes, there is no need of surgery or even if surgery is performed, the testis can be preserved. In such cases, laparoscopy and testicle-sparing surgery would be advisable.[5] If the SGF shows no signs of inflammation or trauma leading to congestion, hemorrhage, or ischemic necrosis, the splenic tissue can be easily separated from the gonad, which would help in preserving the testis. However, in cases where SGF is associated with undescended testis, orchidectomy is a better option.

CONCLUSION

SGF as a rare cause of testicular swelling should be kept in mind and patients with testicular swellings evaluated for the same to avoid unnecessary orchidectomy. The clinicians should also be on the lookout for any other associated congenital defect in such patients.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.