Seminoma

[ Home ] [ Up ]

Pages Below:

• seminoma as a classification refers to pure seminoma upon histopathologic review
  • any nonseminomatous elements (even if seminoma is prevalent) change the classification to nonseminoma.
• serum alpha-fetoprotein (AFP) is within the reference range
  • raised AFP implies nonseminomatous germ cell tumour
• Histopathology of the primary testis often shows a focus of tumour surrounded by fibrous scar, termed burned-out testis cancer

Frequency

• US: Testicular GCTs are rare
  • only 1-2% of all male malignancies and 
  • occurring in 1 of 250 men by age 65 years
  • most common malignancy in men aged 15-35 years. 
  • Incidence rates are 3.7 and 0.9 cases per 100,000 persons per year for whites and blacks, respectively. 
• Internationally: 
  • Incidence of testis cancer has increased from the early 1960s to the mid 1980s
  • Nonwhite populations have a lower incidence than white populations 
  • highest rates are in Denmark (8.4 cases per 100,000 persons per y) and Switzerland (6.2-8.8 cases per 100,000 persons per y), and rates vary across Europe.

History

• Typically, a male aged 15-35 years 
• presents with a painless lump he has had on his testicle for several days to months. 
• Delay in diagnosis is common because of 
  • failure to perform self-examinations, 
  • failure to alert the physician about the mass, or 
  • physician's delay while treating the patient for presumed epididymoorchitis or testicular trauma
• Uncommon presentation 
  • Testicular pain, possibly with an acute onset, 
    • especially when associated with a hydrocele which prevents adequate physical examination. 
  • A testis tumor may become metastatic and manifest with large retroperitoneal and/or chest lesions, while the primary tumor is nonpalpable. Scrotal ultrasonography may locate the primary tumor. . In 1996, Miller and associates reported a series of patients with previous nonpalpable testes that were explored and incorrectly diagnosed as vanished testes. A subsequent seminoma was diagnosed intra-abdominally. 

Stage

• 75% of patients, the seminomas are localized (stage I) at diagnosis. 
• 15% have metastatic disease to the regional lymph nodes
• 5-10% have involvement of juxtaregional nodes or visceral metastases.

Risk Factors

• history of cryptorchidism have a 10- to 40-times increased risk of testis cancer; 
  • 10% of patients with GCTs have a history of cryptorchidism 
  • risk is greater for the abdominal versus inguinal location of undescended testis
  • abdominal testis is more likely to be seminoma, while a testis surgically brought to the scrotum by orchiopexy is more likely to be NSGCT. 
  • Orchiopexy allows for earlier detection by physical examination but does not alter the risk of GCT. 
  • Genetic changes in the form of amplifications and deletions are observed mainly in the 12p11.2-p12.1 chromosomal regions. A gain of 12p sequences is associated with invasive growth of both seminomas and NSGCTs. In contrast, spermatocytic seminoma shows a gain of chromosome 9, while most infantile yolk sac tumors and teratomas show no chromosomal changes. 
• trauma
• mumps
• maternal oestrogen exposure

Investigations

• Patients commonly have abnormal findings on semen analysis at presentation
  • may be subfertile
• scrotal ultrasonography 
  • may identify a nonpalpable testis tumour
    • esp. if for hydrocoele
  • Consider this study for any male with a suspicious or questionable testicular mass that is palpable upon physical examination 
  • Other indications may include 
    • acute scrotal pain (especially when associated with a hydrocele), 
    • nonspecific scrotal pain, 
    • swelling 
    • presence of a mass. 
    • may also be appropriate for males who are at the peak age range for testicular cancer (ie, 15-35 y)
  • commonly shows 
    • a homogeneous hypoechoic intratesticular mass. 
    • Larger lesions may be more inhomogeneous. 
    • Calcifications and cystic areas are less common in seminomas than in nonseminomatous tumors.
• elevated levels of AFP rule out pure seminoma, 
  • secreted by yolk sac elements
  • despite possible contrary histopathologic findings at orchiectomy. 
• Lactate dehydrogenase (LDH) is a less-specific marker for GCTs, but levels can correlate with overall tumor burden
• beta-human chorionic gonadotropin (bhCG). 
  • bHCG is elevated in 5-10% of seminomas
  • elevation may correlate with metastatic disease but not with overall survival
  • if HCG levels do not normalize after orchiectomy, Richie suggests in a 1998 publication to treat patients as if they have NSGCT, citing a study where one third of patients dying of metastatic seminoma were found to have nonseminomatous elements at autopsy. With the 10% incidence of pure seminomas producing bHCG, NSGCT chemotherapy regimens may better serve these patients. 
• Placentalike alkaline phosphatase levels can be elevated in patients with seminoma
  • especially as the tumor burden increases
  • it may also increase with smoking. 
•  CT scanning of the abdomen and pelvis with IV and oral contrast 
  • can be used to identify metastatic disease to the retroperitoneal lymph nodes
  • results in understaging in approximately 15-20% of patients thought to be at stage I
• Chest CT scanning is indicated only when abnormal findings are observed on a chest radiograph. 

Histology

• 3 histologic variants. 

Classic seminoma

• most common histological type
• uniform population of large cells that form sheets and nests separated by delicate connective tissue
• leukocytic infiltration (20%), 
• multinucleated cells, 
• syncytiotrophoblasts (7-35%)
• microcalcifications (60%) 
• gross examination
  • uniform yellow colour and 
  • bulges from the cut surface

Anaplastic seminoma

• 5-15% of patients with seminomas. 
• as described for classic seminoma but with increased mitotic figures
• tend to present at more advanced stages than those with classic seminoma, but stage prognosis is similar

Spermatocytic seminoma

• rare variant
• occurs in older adults
•  tumour cells arranged in solid sheets
• containing poorly developed inconspicuous septae without leukocytic infiltrate
• no glycogen is present
• Small, medium, and large cell types are observed. 
• Orchiectomy alone is sufficient treatment
  • metastases are rare.

Staging

American Joint Committee on Cancer and the International Union Against Cancer: Testicular Cancer Staging System

Primary Tumor (T)

• pTx -  Primary tumor cannot be assessed 
• p0 -  No evidence of primary tumor 
• pTis  - Intratubular germ cell neoplasia 
• pT1 
  • Tumour limited to the testis and epididymis
  • No vascular/lymphatic invasion 
  • May invade the tunica albuginea 
  • No invasion of the tunica vaginalis 
• pT2 
  • Tumour limited to the testis and epididymis 
  • Vascular/lymphatic invasion or tumor extending through the tunica albuginea with involvement of the tunica vaginalis 
  • Invades beyond the tunica albuginea or into the epididymis 
• pT3 Tumour invades the spermatic cord with or without vascular/lymphatic invasion 
• pT4 Tumour invades the scrotum with or without vascular/lymphatic invasion

Regional Lymph Nodes (N): 

• Nx - Nodes not assessed 
• N0 - No regional lymph node metastasis 
• N1 
  • lymph node mass or multiple lymph node masses <2 cm in greatest dimension 
  • <5 nodes positive
• N2 - 
  • Lymph node mass or multiple lymph node masses >2 cm but <5 cm in greatest dimension 
  • >5 nodes positive
  • evidence of extranodal involvment
• N3 - Lymph node mass >5 cm in greatest dimension

Distant Metastases (M)

• M0 No evidence of distant metastases 
• M1a Nonregional nodal or pulmonary metastases 
• M2b Nonpulmonary visceral metastases

Serum Tumor Markers (S)

[ Home ] [ Up ]