Splenogonadal fusion mimicking a testis tumorP Sountoulides1, F Neri1, R Bellocci2, L Schips1, L Cindolo1
1 Department of Urology, S. Pio da Pietrelcina Hospital, Vasto (CH), Italy
2 Department of Pathology, S. Pio da Pietrelcina Hospital, Vasto (CH), Italy
The presence of ectopic splenic tissue in the scrotum is attributed to splenogonadal fusion, a rare congenital anomaly. This ectopic splenic tissue can be an incidental finding or less often present as a scrotal mass later in adult life. Given the rarity of splenogonadal fusion, especially in the adult population, this case highlights the clinical characteristics of the condition, with a special focus on the signs and findings that might help prevent unnecessary orchiectomy.
Keywords: Ectopic spleen, orchiectomy, splenogonadal fusion, testicular mass
Splenogonadal fusion (SGF) is a rare congenital anomaly characterized by an abnormal connection of splenic tissue with the gonads or mesonephric remnants. Although the condition usually presents during childhood, there have been reports of SGF in adults, as incidental findings at scrotal surgery or even more importantly, as scrotal masses. A preoperative diagnosis of this condition can be challenging, as the results of imaging studies are equivocal; thus many of the reported cases have been managed with radical orchiectomy. We will describe a case of SGF mimicking a testis tumor and discuss the clinical characteristics of this condition in terms of diagnosis and surgical management.
A 31-year-old male presented to the Andrology Outpatient Clinic for concerns about fertility. The physical examination of his genital area was normal. Examination of the scrotum, however, revealed a palpable, solid, hard, but painless nodule on the upper pole of his left testicle. The right testis was normal to palpation. The patient denied any history of trauma, scrotal surgery or other intervention and his family history was negative for testicular tumors or any other genetic abnormalities. Scrotal ultrasonography (US) was performed to delineate the nature of the nodule. The US showed a hypoechoic, well-circumscribed lesion, 2.7 to 2.2 cm in diameter, adjacent to the epididymis [Figure 1]. A Color Doppler Ultrasound revealed the higher vascularity of the lesion compared to the testis. The findings were deemed highly suspicious for a testicular tumor. The molecular markers for germ cell tumors were negative and the sperm count was normal.
The patient was consulted about the possibility of a testicular malignancy and gave consent for a scrotal exploration and possible removal of the affected testicle depending on the intraoperative findings.
Via an inguinal incision, the tunica vaginalis was opened and a red-purple mass of approximately 2 × 2 cm was noted encapsulated within the tunica albuginea of the upper pole of the testis. A smooth cord-like structure, arising from the upper part of the lesion, was noted within the tunica vaginalis, connecting the primary lesion with a secondary, smaller, lesion of the same physical characteristics, and then continuing into the inguinal canal [Figure 2]. The testis, epididymis, and spermatic cord were normal in appearance and not suspicious for malignancy on palpation. For this reason and due to the fact that the lesion was clearly distinct from the scrotal components, no intraoperative frozen sections from the testis or epididymis were taken.
A decision was made to dissect and excise the two lesions and spare the testicle. The smaller lesion and the cord-like structure were easily dissected between two Kelly clamps, while the larger lesion attached to the testis was dissected off the testicular parenchyma using cautery. The surface of the testicle was then reconstructed using 3-0 absorbable sutures [Figure 3] and the testicle was repositioned into the scrotal sac. The patient was discharged on the first postoperative day.
The pathology report of the two masses revealed the presence of accessory mature splenic tissue, with no signs of malignancy [Figure 4], representing a continuous type SGF.
Splenogonadal fusion (SGF) is a rare congenital anomaly, characterized by the abnormal connection of the splenic tissue with the gonads or mesonephric remnants.  The involved primordial organs, the splenic anlage in the dorsal mesogastrium, and the gonadal ridge between the mesonephros and dorsal mesentery are formed between five and six weeks of gestation. At week five, as the dorsal mesogastrium rotates to the left, the splenic anlage lies in close proximity to the left gonadal ridge. Inflammation or adhesions of the peritoneal surface of the spleen possibly lead to the fusion of these primordial organs and the subsequent caudal migration. ,
The condition involves young males, as more than 70% of the patients are younger than 20 and approximately 50% are pediatric patients. 
There are two types of SGF: Continuous and discontinuous. In the continuous type, there is a direct anatomic connection between the native spleen and the ectopic splenic tissue through a cord of splenic or fibrous tissue. In the discontinuous type, the ectopic splenic tissue is attached only to the gonad without any attachment to the native spleen. , The scrotal splenic tissue is usually encapsulated within the tunica vaginalis or albuginea, but it is clearly distinct from the gonadal tissue.
Almost one of two patients with continuous-type SGF presents with a congenital disorder, with cryptorchidism, (31%) limb defects, and micrognathia being the most common. The less common anomalies include cardiac, lung, and intestinal defects, spina bifida, and craniosynostosis. , In our case of continuous-type SGF, however, no congenital anomaly was present.
Discontinuous-type SGF is rarely associated with congenital abnormalities, although there are reports of SGF associated with infertility, testicular aplasia, and atrophy. ,,
Regardless of its type, SGF is usually an incidental finding during groin exploration for cryptorchidism or hernia repair. SGF in adults may present as painful,  or as in our case, painless, scrotal enlargement of undifferentiated origin, and for that reason, it is usually recognized following radical inguinal orchiectomy for suspected neoplasia. ,
The left testis is almost always affected, as in our case, due to the anatomical proximity of the spleen with the left gonad during embryogenesis. 
The role of imaging studies in the diagnosis of SGF is controversial. US findings are variable and inconclusive, especially in cases of discontinuous SGF, where the diagnosis is usually confirmed following orchiectomy.  US findings suggestive of a continuous type SGF include the detection of an intra-abdominal band of hypoechoic tissue originating from the affected testis and extending cranially toward the spleen. 
Although rarely performed preoperatively, a contrast-enhanced CT scan may reveal a cord-like tissue between the spleen and the left scrotal mass, a finding compatible with continuous type splenogonadal fusion (SGF). 
On the basis of a strong suspicion, the diagnosis may be confirmed by MRI or a technetium-99m sulfur colloid liver - spleen scan. On MRI, T2-weighted imaging sequence will demonstrate an isointense tubular structure connecting the spleen to the testis. ,
In our case, preoperative axial imaging was not deemed necessary as this was considered to be a straightforward case for scrotal exploration due to the high level of suspicion for malignancy.
With regard to the possibility of malignancy associated with SGF in adults, the fourth case since 1980, of a tumor arising within an SGF was recently reported.  Interestingly, all four cases were associated with cryptorchidism and infertility, both known etiological factors for testicular malignancy. Therefore, a cause and effect relationship between SGF and malignancy cannot be established.
However, in order to avoid an unnecessary orchiectomy in cases where malignancy is a concern an inguinal incision with control of the cord, inspection, and possible biopsy of the mass are recommended.
Splenogonadal fusion remains differential in the diagnosis of a scrotal mass. Suspicion should be aroused in cases of left-sided masses that are attached, but are clearly distinct from the testis and associated with congenital anomalies. Confirmation of the nature of the lesion with the aid of US or MRI, coupled with clinical findings, will likely limit the operative intervention to partial orchidectomy or enucleation of the splenic tissue, as in the case presented.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]