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PubMed This is a summary of 18 peer-reviewed journal articles Updated
Urology · Testicular Seminoma

Symptoms and Diagnostic Pitfalls of Testicular Seminoma

At a Glance

The most common symptom of testicular seminoma is a painless lump or heaviness in the testicle. Because symptoms mimic benign conditions like infections or fluid cysts, initial misdiagnosis is common. A scrotal ultrasound is the essential tool to distinguish a solid tumor from benign swelling.

It is common for men to feel a mix of confusion and frustration during the diagnostic process for testicular cancer. Because the initial symptoms often mirror much less serious conditions, many patients find themselves on a “diagnostic detour” before reaching the correct answer. Understanding the typical presentation and the pitfalls of early diagnosis can help you navigate this period with clarity.

The Most Common Signs

The hallmark of testicular seminoma is usually a painless, palpable mass or swelling in one testicle [1][2]. You might notice:

  • A firm, painless lump that feels like it is part of the testicle itself [3].
  • A general feeling of “heaviness” or a dull ache in the lower abdomen or scrotum [4].
  • An increase in the size of one testicle, even without a distinct lump [1].

While seminomas are famously painless, some men do experience discomfort [5]. In rare cases, the first symptoms might not be in the scrotum at all, but rather back pain or a lump in the neck, which can occur if the cancer has begun to spread [6][7].

Why Delays Happen: The “Great Mimickers”

If your doctor initially told you that you had an infection or a benign fluid collection, you are not alone. Testicular cancer is frequently misdiagnosed at first because its symptoms are almost identical to several common, non-cancerous conditions [4][8]:

  1. Epididymitis/Orchitis: These are inflammations or infections of the tubes or the testicle itself. They usually cause pain and swelling, and doctors often treat them with antibiotics first [9]. If a mass does not shrink after a course of antibiotics, further investigation is essential [1].
  2. Hydrocele: This is a buildup of fluid around the testicle that causes swelling [10]. While a hydrocele is benign, it can sometimes hide a tumor underneath the fluid [11].
  3. Varicocele: This is an enlargement of the veins within the scrotum, often described as feeling like a “bag of worms.”

It is important to know that a delay of a few weeks while trying antibiotics is common and usually does not change the excellent long-term prognosis of seminoma [12][13]. However, if symptoms persist, you must advocate for definitive imaging.

The Deciding Factor: Scrotal Ultrasound

The single most important tool for clearing up diagnostic confusion is a high-frequency scrotal ultrasound [14][15]. This test uses sound waves to create a detailed picture of the inside of the scrotum.

An ultrasound is exceptionally good at telling the difference between:

  • Fluid vs. Solid: It can instantly see if a swelling is a simple fluid sac (hydrocele) or a solid tumor [16].
  • Location: It determines if a lump is intratesticular (inside the testicle, which is more likely to be suspicious) or extratesticular (on the outside structures, which is often benign) [8].
  • Blood Flow: Using Color Doppler, the technician can see the blood flow patterns. While infections often show greatly increased blood flow (hyperemia), solid tumors typically exhibit chaotic internal blood flow that helps distinguish them from benign fluid cysts [17][18].

If the ultrasound identifies a solid mass within the testicle, the standard next step is surgical consultation. This imaging provides the evidence needed to move from “watching and waiting” to taking definitive action.

Common questions in this guide

Why was I initially prescribed antibiotics for a testicular lump?
Testicular cancer symptoms often mimic common infections like epididymitis or orchitis. Doctors frequently prescribe antibiotics first to rule out an infection, but a testicular mass that does not shrink after treatment requires further imaging.
What will a scrotal ultrasound show?
A scrotal ultrasound creates a detailed picture of the testicle to determine if a swelling is a benign fluid sac or a solid tumor. It also checks blood flow patterns and confirms whether the mass is located inside or outside the testicle.
Is a hydrocele a sign of testicular cancer?
A hydrocele is a benign buildup of fluid around the testicle and is not cancer. However, this fluid can sometimes hide an underlying tumor, making an ultrasound essential to ensure there is no hidden mass.
Should I be worried if my testicular lump doesn't hurt?
Yes, the most common sign of a testicular seminoma is a firm, painless lump or swelling. Any new, persistent mass in the testicle should be evaluated by a doctor, even if it causes absolutely no discomfort.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Could this mass be a benign condition like epididymitis, and if so, how can we be sure?
  2. 2.Does my ultrasound show any signs of increased blood flow (vascularity) within the mass?
  3. 3.If I was previously treated with antibiotics for this, why didn't the swelling go away?
  4. 4.Was the mass found entirely inside the testicle (intratesticular) or was it attached to the outside (extratesticular)?
  5. 5.How quickly should we proceed with the next steps now that the ultrasound has identified a solid mass?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (18)
  1. 1

    Spontaneous gas in a retroperitoneal mass: check the testis!

    Dana J, Maxwell F, Eiss D, Rocher L

    International braz j urol : official journal of the Brazilian Society of Urology 2019; (45(4)):847-850 doi:10.1590/S1677-5538.IBJU.2018.0606.

    PMID: 31038859
  2. 2

    Unmasked Testicular Seminoma During Use of Hormonal Transgender Woman Therapy: A Hidden hCG-Secreting Tumor.

    Elshimy G, Tran K, Harman SM, Correa R

    Journal of the Endocrine Society 2020; (4(7)):bvaa074 doi:10.1210/jendso/bvaa074.

    PMID: 32666014
  3. 3

    Retroperitoneal Mass, Abdominal Pain, and Bilateral Hydronephrosis Caused by Testicular Seminoma: A Case Report and Review of the Literature.

    Fadeyi O, Saghari S, Esmaeili A, et al.

    Cureus 2025; (17(3)):e81391 doi:10.7759/cureus.81391.

    PMID: 40166779
  4. 4

    Modern Management of Testicular Cancer.

    Chen J, Daneshmand S

    Cancer treatment and research 2018; (175()):273-308 doi:10.1007/978-3-319-93339-9_13.

    PMID: 30168127
  5. 5

    Nodular expression of seminoma in the neck: An unusual case presentation.

    Crawford CK, Yasrab M, Fishman EK

    Radiology case reports 2025; (20(2)):1124-1129 doi:10.1016/j.radcr.2024.11.020.

    PMID: 39691761
  6. 6

    Testicular seminoma presenting as a large conglomerate mass in abdomen.

    Sriselvakumar S, Meehan L

    Radiology case reports 2024; (19(7)):2639-2643 doi:10.1016/j.radcr.2024.03.012.

    PMID: 38645951
  7. 7

    A case of cervical spinal mass with cord compression and rib bone metastasis from presumably burned-out seminomatous testicular germ cell tumor.

    Wu AH, Kaur S, Peng S, et al.

    The Canadian journal of urology 2019; (26(3)):9799-9801.

    PMID: 31180313
  8. 8

    Testicular Germ Cell Tumours-The Role of Conventional Ultrasound.

    Belfield J, Findlay-Line C

    Cancers 2022; (14(16)) doi:10.3390/cancers14163882.

    PMID: 36010875
  9. 9

    Is follow-up ultrasound necessary after acute epididymitis? A retrospective analysis from a large university hospital.

    Capet J, Sønsksen J, Bisbjerg R, Fode M

    Scandinavian journal of urology 2018; (52(5-6)):445-447 doi:10.1080/21681805.2018.1545797.

    PMID: 30600755
  10. 10

    Testicular metastasis of colon cancer masquerading a hydrocele of testis.

    Sakuma T, Aoki K, Ando M, et al.

    Urology case reports 2021; (39()):101868 doi:10.1016/j.eucr.2021.101868.

    PMID: 34646739
  11. 11

    Ultrasonography of the scrotum: Revisiting a classic technique.

    Tsili AC, Bougia CK, Pappa O, Argyropoulou MI

    European journal of radiology 2021; (145()):110000 doi:10.1016/j.ejrad.2021.110000.

    PMID: 34741987
  12. 12

    [CCAFU french national guidelines 2016-2018 on testicular germ cell tumors].

    Durand X, Fléchon A, Murez T, et al.

    Progres en urologie : journal de l'Association francaise d'urologie et de la Societe francaise d'urologie 2016; (27 Suppl 1()):S147-S165 doi:10.1016/S1166-7087(16)30706-0.

    PMID: 27846929
  13. 13

    Impact and Risk Factors of Diagnostic Delay in Patients With Testicular Cancer: A Multicenter Retrospective Study.

    Honda K, Kawai T, Taguchi S, et al.

    International journal of urology : official journal of the Japanese Urological Association 2025; (32(11)):1593-1601 doi:10.1111/iju.70187.

    PMID: 40726135
  14. 14

    Testicular Seminoma and Its Mimics: From the Radiologic Pathology Archives.

    Marko J, Wolfman DJ, Aubin AL, Sesterhenn IA

    Radiographics : a review publication of the Radiological Society of North America, Inc 2017; (37(4)):1085-1098 doi:10.1148/rg.2017160164.

    PMID: 28574809
  15. 15

    Elastographic Imaging of Anaplastic Seminoma of Testis With Its Ultrasound and Doppler Correlation: A Case Report.

    Bhansali PJ, Phatak SV, Mishra GV, Nagendra V

    Cureus 2022; (14(12)):e32813 doi:10.7759/cureus.32813.

    PMID: 36699755
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    Incidental Findings and How to Manage Them: Testis- A WFUMB Position Paper.

    Lewicki A, Freeman S, Jędrzejczyk M, et al.

    Ultrasound in medicine & biology 2021; (47(10)):2787-2802 doi:10.1016/j.ultrasmedbio.2021.05.022.

    PMID: 34303560
  17. 17

    Paediatric acute epididymo-orchitis temporally related to SARS-CoV-2 infection: A case series and review of the literature.

    Hoffmann K, Gopal M

    Journal of pediatric urology 2024; (20(1)):91-94 doi:10.1016/j.jpurol.2023.09.017.

    PMID: 37806834
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    Emphysematous epididymo-orchitis: An unusual case report.

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This page is for informational purposes only and does not replace professional medical advice. If you notice a persistent testicular lump or swelling, consult a urologist or healthcare provider for a prompt evaluation.

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