Epididymal Cyst: Symptoms, Types, Causes and Treatment

Epididymal cysts are a common finding in male urology, often discovered incidentally during examinations or imaging. While generally benign, their presence can spark concern, especially if they grow in size or cause discomfort. This comprehensive guide delves into the key aspects of epididymal cysts—including their symptoms, types, underlying causes, and evidence-based treatment options—so patients and caregivers can make informed decisions.

Symptoms of Epididymal Cyst

Epididymal cysts often remain unnoticed, but when symptoms do arise, they can impact daily comfort and lead to medical consultations. Understanding these symptoms is crucial for early identification and appropriate management.

Symptom	Description	Frequency/Severity	Source(s)
Swelling	Painless scrotal lump/swelling	Most common, usually mild	1 2
Orchialgia	Scrotal/testicular pain	Less common, varies	1
Asymptomatic	No visible symptoms	Very frequent	1 2 3
Bilaterality	Cysts on both sides	Rare, mostly in children	2

Table 1: Key Symptoms

Swelling and Lump Formation

Epididymal cysts most frequently present as a painless, palpable swelling in the scrotum. This lump is usually soft and smooth, distinguishable from the testicle itself. Patients may notice it during self-exams or it may be found during a clinical examination for another issue 1.

Pain and Discomfort (Orchialgia)

While many cysts are painless, some individuals may experience mild to moderate aching or heaviness in the scrotum. This discomfort, called orchialgia, can become more pronounced as the cyst grows, but is not universally present 1.

Asymptomatic Presentation

Most epididymal cysts are asymptomatic, especially when small. They are often detected incidentally during scrotal ultrasound for unrelated reasons 1 2 3. This silent nature means many men are unaware they have a cyst until it is picked up during routine checks.

Bilateral Occurrence

Though usually unilateral, cysts can occasionally form on both sides (bilateral), which is especially rare in children. Bilateral cysts can follow the same symptom pattern as single-sided cysts and may also resolve spontaneously 2.

Types of Epididymal Cyst

Not all epididymal cysts are the same—understanding their variations helps guide diagnosis and management. Below, we outline the main types and their distinct features.

Type	Location/Structure	Notable Features	Source(s)
Unilocular	Single fluid-filled sac	Most common type	1
Multilocular	Multiple compartments	Less common, larger	1
Bilateral	Both epididymides	Rare, mainly in kids	2
Head/Tail	Head or tail of epididymis	Tail cysts: rare	2 3

Table 2: Types of Epididymal Cyst

Unilocular vs. Multilocular Cysts

• Unilocular cysts are the most frequent, presenting as a single, round or oval fluid collection within the epididymis, typically at the head.
• Multilocular cysts contain several interconnected compartments. These can be larger and sometimes more noticeable on physical exam or imaging 1.

Bilateral Cysts

Bilateral epididymal cysts occur on both sides. They are uncommon, especially in children, but can occur and sometimes resolve on their own without intervention 2.

Location: Head vs. Tail

Most cysts develop in the head (upper part) of the epididymis, where sperm is stored and matured. Cysts arising in the tail are much rarer 2. The location can influence both the clinical presentation and the approach to treatment.

Causes of Epididymal Cyst

Understanding the origins of epididymal cysts sheds light on both prevention and management. While many cases develop spontaneously, research points to several biological and environmental factors.

Cause	Mechanism/Description	Risk Group/Factor	Source(s)
Developmental/Idiopathic	Unknown, often spontaneous	General population	1 2
Hormonal (Estrogen)	Fetal/childhood estrogen exposure	DES-exposed individuals	3
Anatomical Disruption	Blockage of epididymal ducts	Varies	1 3
Genetic/Experimental	Shown in animal models, ERKO mice	Research/experimental	3

Table 3: Causes of Epididymal Cyst

Developmental and Idiopathic Factors

Most epididymal cysts arise without a clear cause—termed "idiopathic." They are thought to be the result of minor developmental anomalies or local disruptions in the epididymal ducts that result in fluid accumulation 1 2.

Hormonal Influence and Estrogen Exposure

Research has highlighted a link between estrogen exposure (particularly in fetal life) and the formation of epididymal cysts. The most well-documented human example is the synthetic estrogen diethylstilbestrol (DES), which, when taken during pregnancy, increases the risk of cyst formation in male offspring 3. Animal studies also show that abnormal estrogen signaling can disrupt normal fluid absorption in the epididymis, leading to cyst development.

Anatomical Blockage

Obstruction or disruption of the tiny ducts within the epididymis—due to inflammation, trauma, or infection—can cause local fluid buildup and cyst formation 1 3. However, this is less commonly established in routine clinical cases.

Genetic and Experimental Insights

Experimental models, such as estrogen receptor knockout (ERKO) mice, provide evidence for a genetic/hormonal basis for cyst formation, but clear genetic syndromes in humans are rare 3.

Treatment of Epididymal Cyst

Treatment for epididymal cysts is tailored to the size of the cyst, symptoms, patient age, and preferences. Most cysts require minimal intervention, but several effective options exist for troublesome cases.

Treatment	Indications	Effectiveness/Considerations	Source(s)
Observation	Small, asymptomatic cysts	High spontaneous resolution	1 2
Aspiration	Moderate-sized, symptomatic	Moderate success, may recur	1 5
Sclerotherapy	Persistent/recurrent cysts	High cure, low complications	4 5 6 7 8
Surgical Excision	Large, failed conservative tx	Definitive, more complications	1 5

Table 4: Epididymal Cyst Treatment Options

Observation and Watchful Waiting

• Best for: Small, asymptomatic cysts (less than 10 mm)
• Effectiveness: Most small cysts resolve spontaneously, especially in children and young adults. Observation avoids unnecessary procedures and costs 1 2.
• Approach: Regular monitoring, with intervention only if the cyst enlarges or becomes painful.

Aspiration

• Best for: Moderate-sized cysts (11–20 mm) causing discomfort
• Effectiveness: Aspiration (removal of cyst fluid with a needle) can provide symptom relief but recurrence is possible. May be combined with sclerotherapy for better results 1 5.

Sclerotherapy

Sclerotherapy involves injecting a solution (e.g., tetracycline, sodium tetradecyl sulfate, or polidocanol) into the cyst after aspiration to induce fibrosis and closure of the cyst cavity.

• Best for: Recurrent or persistent cysts, especially in adults and older patients 4 5 6 7 8
• Effectiveness: High cure rates (up to 100% in some series), low recurrence, and minor side effects. Multiple types of sclerosant agents have shown good results:
  • Sodium tetradecyl sulfate 7
  • Tetracycline 8
  • Polidocanol 6
• Benefits: Minimally invasive, low complication rate, performed on an outpatient basis, short recovery time.

Surgical Excision

• Best for: Large cysts (over 20 mm), failed conservative/sclerotherapy approaches, or when malignancy cannot be excluded 1 5
• Effectiveness: Offers definitive cure but carries higher risk of complications such as hematoma, infection, and longer recovery 5.
• Considerations: Usually reserved for persistent or complicated cases.

Conclusion

Epididymal cysts are common, typically benign fluid collections that can affect males of all ages. Their management depends on size, symptoms, and patient preferences. Here’s a summary of key points:

• Symptoms: Most epididymal cysts are asymptomatic, but some present as painless scrotal swelling or mild discomfort.
• Types: They may be unilocular or multilocular, unilateral or bilateral, and most often arise from the epididymal head.
• Causes: While many cysts develop spontaneously, some are linked to hormonal factors, especially fetal estrogen exposure.
• Treatment: Small, symptomless cysts often resolve naturally; moderate-to-large or symptomatic cysts may require aspiration, sclerotherapy, or surgical excision. Sclerotherapy is highly effective and minimally invasive in adults.

By understanding the full spectrum of epididymal cysts—from silent to symptomatic, from observation to intervention—patients and clinicians can choose the most appropriate, evidence-based path to care.