Spermatic Cord Cyst Presenting as an Incarcerated Inguinal Hernia: An Unusual Case and Literature Review

Inguinal cord cysts are a rare finding, comprising less than 1% of inguinal hernia dissections [1]. These are benign masses of atypical tissue found within the inguinal cord that are anatomically different from hydroceles and hernias. They deserve attention not only as an unusual finding, but for their typical presentation as incarcerated inguinal hernias and the topics of preoperative imaging and planning that they bring to the forefront. We present an atypical case and a review of the literature.


Introduction
Inguinal cord cysts are a rare finding, comprising less than 1% of inguinal hernia dissections [1]. These are benign masses of atypical tissue found within the inguinal cord that are anatomically different from hydroceles and hernias. They deserve attention not only as an unusual finding, but for their typical presentation as incarcerated inguinal hernias and the topics of preoperative imaging and planning that they bring to the forefront. We present an atypical case and a review of the literature.

Case Report
A nineteen-year-old male with a history of a right inguinal hernia repair at the age of four, presented with a left groin lump of one-month duration that subjectively felt similar to his prior right hernia. The patient had pain with exertion, but no obstructive symptoms. He reported to his primary care provider with some erythema overlying his non-reducible bulge and he was sent to the hospital. In the emergency department, an ultrasound was performed and a non-reducible collection with heterogeneous intraluminal contents and a hernia neck was reported; consistent with a bowel-contianinghernia ( Figure 1). He was consented for an inguinal hernia repair and taken to the operating room. Intraoperatively, he was found to have no hernia, but a cystic mass on the spermatic cord. The mass was intimately attached to vessels within the cord. It was dissected off the cord leaving all vessels and structures intact with a small button of tissue remaining. Final histopathological diagnosis was pseudocyst, which has not been reported in the literature ( Figure 1). The patient recovered well with resolution of pain at postoperative follow up.

Discussion
Inguinal cord cysts are anatomically distinct from cord lipomas and hydroceles. They are most commonly benign masses of atypical tissue. Most cysts are caused by mesothelial hyperplasia when flawed obliteration of an embryonal structure such as the process us vaginalis or canal of nuck occurs [1,2]. They are often found at the end of an indirect inguinal hernia sack. Islands of remnant embryologic tissue such as adrenal cortical rests are found in approximately 4% of male children undergoing surgery for inguinal hernia or undescended testes [1]. When approaching a groin mass that presents similar to an incarcerated inguinal hernia, one must have a wide differential diagnosis. Aberrant tissue has been discovered in the inguinal canal with or without hernia, these include: adrenal cortical tissue, uterine fibroids, endometriosis, ovary, pancreatic pseudocyst, lymph nodes [3]. Infectious etiology is another possibility for groin bulge and includes diverticular abscesses [3]. Traumatic etiology includes a delayed presentation of a ruptured spleen and spermatic cord hematomas [4]. Neoplasia is an etiology of high concern with the possibility of metastatic disease and includes: dermoid cysts and liposarcoma [1].
The variety of mimics of a bowel-containing incarcerated hernia makes counselling the patient important and brings up the topic of pre-operative imaging. The hernia sac is difficult to discern on ultrasound [5]. When analyzing the contents of a hernia sac omental fat is typically hyperechoic, fluid is anechoic, and bowl contents are seen as a mixed pattern due to the heterogeneous mixture of air and semisolids [5]. The ultrasound appearance for our patient is most definitely mixed and therefore may have caused confusion ( Figure  1). Groin masses can also be confusing in female patients. Round ligament varicosities have been mistaken for inguinal hernias in pregnancy, resulting in unnecessary surgery in a high-risk patient [6]. This further emphasizes the need for accurate interpretation of ultrasonography.
When anon-reducible groin bulge presents it is important to keep a wide differential and analyze the clinical picture, paying close attention to the chronicity of lesions. When ordering imaging it may be beneficial to ask the radiologist to evaluate for more than just a hernia and rather a groin mass, keeping the door open for alternative diagnoses. Uncertainty can always be followed with further imaging such as CT to better prepare the surgeon and the patient for operative expectations such as a cancer operation and potential need for orchiectomy. When performing an operation on an incarcerated inguinal hernia an anterior open approach offers the best exposure. Laparoscopic and preperitoneal approaches may miss these masses as they are typically found at the distal tip of the indirect sack external to the transversalis fascia. Retained inguinal cord cysts have a high risk of continuing to cause symptoms postoperatively, resulting in reoperation. We did leave a small button of tissue yet recurrence was not seen six months postoperatively. If preoperative imaging is correctly interpreted, a difficult dissection with possible damage to testicular blood supply can be anticipated. Depending on the type of cyst found, complete excision may be required to prevent recurrence and a hernia repair may or may not be required.