Seminoma
~Introduction
Seminoma is a malignant germ cell tumor of the testis and represents one of the most common and highly curable cancers in young adult males. It arises from primordial germ cells and belongs to the group of testicular germ cell tumors (TGCTs). Seminomas are characterized by slow growth, radiosensitivity, and excellent prognosis, especially when detected early.
Testicular cancers account for about 1–2% of all male malignancies, but they are the most common solid tumors in men aged 15–40 years. Among these, seminoma constitutes approximately 50–60% of cases. Due to advances in diagnosis, imaging, chemotherapy, and radiotherapy, the survival rate for seminoma exceeds 95%, making it one of the most treatable cancers.
~Definition
Seminoma is a malignant germ cell tumor composed of uniform cells resembling primordial germ cells, typically arising in the testis, and less commonly in extragonadal sites such as the mediastinum or retroperitoneum.
~Epidemiology
Accounts for 50–60% of testicular germ cell tumors
Most common age group: 30–45 years
Rare before puberty
Higher incidence in Caucasian males
Incidence has been increasing globally
Bilateral involvement is rare (1–2%)
~Etiology and Risk Factors
The exact cause of seminoma is unknown, but several risk factors have been identified.
1. Cryptorchidism
Undescended testis increases risk by 3–10 times
Risk persists even after orchiopexy
2. Genetic Factors
Family history of testicular cancer
Mutations involving KIT gene
Isochromosome i(12p) is characteristic
3. Gonadal Dysgenesis
Klinefelter syndrome
Testicular atrophy
4. Environmental Factors
Prenatal estrogen exposure
Endocrine-disrupting chemicals
5. Previous Testicular Cancer
Increased risk of contralateral seminoma
~Pathogenesis
Seminoma develops from germ cell neoplasia in situ (GCNIS), formerly known as carcinoma in situ. Under the influence of hormonal and genetic alterations, these precursor cells transform into malignant seminoma cells.
Key molecular features include:
Overexpression of KIT receptor
Gain of chromosome 12p
Expression of placental alkaline phosphatase (PLAP)
~Gross Pathology
Testis is enlarged and firm
Tumor appears homogeneous, gray-white, and lobulated
Lacks hemorrhage and necrosis (unlike non-seminomatous tumors)
Tunica albuginea may be stretched but usually intact
~Microscopic (Histopathological) Features
Classic histological features include:
Sheets or nests of large uniform cells
Cells have:
Clear or pale cytoplasm (glycogen-rich)
Large central nuclei
Prominent nucleoli
Tumor cells separated by fibrous septa
Septa infiltrated by lymphocytes
Occasional granulomas
Minimal pleomorphism
Immunohistochemistry
Positive for:
PLAP
OCT3/4
KIT (CD117)
Negative for AFP
~Types of Seminoma
1. Classical Seminoma
Most common type
Occurs in adults
Typical histological appearance
2. Spermatocytic Tumor (formerly spermatocytic seminoma)
Occurs in older men (>50 years)
Slow growing
Rarely metastasizes
Better prognosis
~Clinical Features
Primary Symptoms
Painless testicular swelling or mass
Heaviness in the scrotum
Associated Symptoms
Dull ache in groin or lower abdomen
Back pain (due to retroperitoneal lymph node involvement)
Gynecomastia (rare, due to hCG secretion)
Advanced Disease Symptoms
Weight loss
Cough or dyspnea (lung metastasis)
Bone pain (rare)
~Tumor Markers
Tumor markers play a crucial role in diagnosis, staging, and follow-up.
| Marker | Role in Seminoma |
|---|---|
| β-hCG | Mildly elevated in ~15–30% |
| AFP | Always normal (if elevated → non-seminoma) |
| LDH | Reflects tumor burden |
~Diagnosis
1. Clinical Examination
Palpation of firm, non-tender testicular mass
2. Scrotal Ultrasound
First-line investigation
Hypoechoic, homogeneous lesion
3. Serum Tumor Markers
β-hCG, AFP, LDH
4. Radical Inguinal Orchiectomy
Diagnostic and therapeutic
Trans-scrotal biopsy contraindicated
5. Imaging for Staging
CT scan of abdomen and pelvis
Chest X-ray or CT chest
~Staging (TNM Classification)
Stage I
Tumor confined to testis
Stage II
Spread to retroperitoneal lymph nodes
Stage III
Distant metastasis (lungs, liver, brain)
~Treatment of Seminoma
Seminoma is highly radiosensitive and chemosensitive.
1. Radical Inguinal Orchiectomy
Standard initial treatment
Removes primary tumor
2. Management by Stage
Stage I Seminoma
Options include:
Active surveillance
Adjuvant radiotherapy
Single-agent chemotherapy (Carboplatin)
Preferred: Surveillance in compliant patients
Stage II Seminoma
Stage IIA/IIB: Radiotherapy or chemotherapy
Stage IIC: Combination chemotherapy
Stage III Seminoma
Combination chemotherapy (BEP regimen):
Bleomycin
Etoposide
Cisplatin
~Radiotherapy
Seminoma is extremely radiosensitive
Target areas:
Para-aortic lymph nodes
Used mainly in early stages
Long-term risks: secondary malignancies, cardiovascular disease
~Chemotherapy
Platinum-based regimens
Highly effective even in advanced disease
Side effects:
Nephrotoxicity
Ototoxicity
Pulmonary toxicity (Bleomycin)
~Prognosis
Seminoma has one of the best prognoses among all cancers.
| Stage | 5-Year Survival |
|---|---|
| Stage I | >99% |
| Stage II | 95–98% |
| Stage III | 85–90% |
Prognosis depends on:
Stage at diagnosis
Tumor marker levels
Response to therapy
~Complications
Disease-Related
Metastasis to lymph nodes, lungs
Infertility
Treatment-Related
Secondary malignancies
Cardiovascular disease
Pulmonary fibrosis
Hormonal imbalance
~Prevention and Screening
Testicular self-examination
Early evaluation of scrotal swelling
Early orchiopexy for cryptorchidism
Long-term follow-up of high-risk individuals
~Follow-Up and Surveillance
Regular follow-up includes:
Physical examination
Tumor markers
Imaging studies
Monitoring fertility and hormonal status
Follow-up is essential due to risk of:
Late relapse
Second primary tumors
~Conclusion
Seminoma is a highly curable malignant germ cell tumor of the testis, predominantly affecting young adult males. Early diagnosis, accurate staging, and appropriate treatment result in excellent survival outcomes. Advances in imaging, chemotherapy, and surveillance strategies have reduced treatment-related morbidity while maintaining high cure rates. Awareness, early detection, and long-term follow-up remain key components in the effective management of seminoma.
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