How should an enlarged epididymal head be evaluated and managed?

Evaluation and Management of Enlarged Epididymal Head

An enlarged epididymal head should be evaluated immediately with scrotal ultrasound with color Doppler to differentiate between infectious/inflammatory causes (epididymitis) and solid masses (benign adenomatoid tumor vs. rare malignancy), as this distinction determines whether conservative medical management or surgical excision is required. 1

Initial Diagnostic Approach

Ultrasound Imaging

• Perform scrotal ultrasound with both grayscale and color Doppler as the first-line diagnostic test, which provides approximately 100% sensitivity for detecting intrascrotal masses and 98-100% accuracy for distinguishing intratesticular from extratesticular lesions. 1, 2
• Power Doppler is particularly valuable because of its increased sensitivity to low-flow states and independence from Doppler angle correction. 1
• The ultrasound must determine whether the mass is cystic or solid, as extratesticular masses with liquid content are generally benign while solid masses require further evaluation. 3, 4

Clinical Assessment

• Obtain focused history including: onset of symptoms (acute vs. gradual), presence of pain, fever, dysuria, urethral discharge, recent sexual activity, history of urinary tract infections, and any prior scrotal trauma or surgery. 1
• Perform physical examination assessing for: scrotal skin erythema and thickening, testicular size and consistency, presence of hydrocele, inguinal lymphadenopathy, and urethral discharge. 1
• Check vital signs including temperature to identify systemic infection. 1

Differential Diagnosis Based on Ultrasound Findings

Acute Epididymitis (Most Common Cause)

Ultrasound findings:

• Enlarged and hypoechoic epididymis due to edema, with the head being involved in 17.9% of cases as the predominant site. 5
• Increased blood flow on color Doppler imaging (hyperemia) is the key diagnostic feature, with sensitivity approaching 100% for detecting scrotal inflammation. 1, 5
• Associated findings include reactive hydrocele (45.5% of cases), scrotal wall thickening, and concomitant orchitis in 20-47% of patients. 1, 5

Laboratory evaluation:

• Obtain urethral swab or first-void urine for nucleic acid amplification testing for N. gonorrhoeae and C. trachomatis. 1
• Perform urinalysis and urine culture if enteric organisms are suspected (particularly in men >35 years). 1
• Check complete blood count if systemic infection is suspected. 1

Management:

• For sexually transmitted epididymitis (men <35 years or with risk factors): Ceftriaxone 250 mg IM once PLUS Doxycycline 100 mg orally twice daily for 10 days. 1
• For enteric organism epididymitis (men >35 years): Ofloxacin 300 mg orally twice daily for 10 days OR Levofloxacin 500 mg orally once daily for 10 days. 1
• Adjunctive measures include bed rest, scrotal elevation, and analgesics until fever and inflammation subside. 1
• Failure to improve within 3 days requires reevaluation of diagnosis and consideration of alternative pathology including abscess or tumor. 1

Solid Epididymal Mass

Adenomatoid tumor (most common benign epididymal neoplasm):

• Appears as a well-defined, hypoechoic to anechoic nodular mass, most commonly in the epididymal tail but can occur in the head. 3, 6
• These are benign mesothelial-origin tumors that typically present as painless, firm, encapsulated masses. 6
• Characteristic echo patterns on ultrasound permit conservative surgical approach with scrotal access rather than inguinal orchiectomy. 6

Malignant considerations:

• Malignant extratesticular neoplasms are rare but include rhabdomyosarcoma, liposarcoma, leiomyosarcoma, and lymphoma, which are often large at presentation. 3
• Any solid extratesticular mass that is enlarging, heterogeneous, or lacks characteristic benign features should undergo surgical excision for definitive histological diagnosis. 3, 4

Epididymal Cyst or Spermatocele

• Appear as well-defined anechoic (fluid-filled) structures, easily diagnosed with ultrasound and uniformly benign. 3
• No treatment required unless symptomatic or causing significant discomfort. 3

Critical Pitfalls to Avoid

Misdiagnosis of Torsion

• Reperfusion after early ischemia from torsion/detorsion can induce reactive hyperemia on color Doppler that is sonographically indistinguishable from acute epididymoorchitis. 1
• Correlation with clinical presentation is essential: torsion typically presents with sudden-onset severe pain, while epididymitis has gradual onset with fever and dysuria. 1
• The "whirlpool sign" (spiral twist of spermatic cord) is the most specific ultrasound finding for torsion. 1

Overlooking Testicular Involvement

• Always assess the ipsilateral testis for size, echogenicity, and perfusion, as concomitant orchitis occurs in 20-47% of epididymitis cases and is associated with testicular enlargement and increased pain. 1, 5
• Measure testicular volume bilaterally; volumes <12 mL warrant additional evaluation for underlying testicular pathology or hormonal dysfunction. 2, 7

Inadequate Follow-up

• For epididymitis, persistent swelling after 3 months of treatment (occurs in 17.8% of cases) requires repeat ultrasound to exclude underlying mass. 5
• For solid masses managed conservatively (if <5 mm and benign-appearing), serial ultrasound examinations every 3-6 months are mandatory to detect enlargement. 8

Special Populations

Infertility Evaluation

• Men undergoing infertility workup have a 34% incidence of focal sonographic abnormalities, with 14% showing hypoechoic lesions. 8
• Incidental testicular or epididymal lesions <5 mm with negative tumor markers may be initially observed with serial ultrasound rather than immediate surgical excision, as these are usually benign in the infertility population. 8
• Enlarging lesions or those >5 mm should undergo histological examination. 8

Pediatric Patients

• Ultrasound duplex Doppler is the appropriate initial imaging for acute scrotal pathology in children, with the same diagnostic accuracy as in adults. 1
• False-positive Doppler evaluations can occur in infants and young boys who often have normally reduced intratesticular blood flow; use the contralateral testis as an internal control. 1