Testicular tumors

Understanding testicular tumors is critical for medical students preparing for the USMLE Step 1. Here, we’ll explore the types, origins, histological features, clinical presentation, and key points related to testicular tumors.

Types of Testicular Tumors

Testicular tumors are broadly categorized into two main groups:

Germ Cell Tumors (95%)
Sex Cord Stromal Tumors (5%)

Germ Cell Tumors

Germ cell tumors originate from the cells that produce sperm and are the most common type of testicular tumors. They usually occur in young men, with risk factors including cryptorchidism and Klinefelter syndrome. Germ cell tumors are usually not biopsied to avoid scrotal seeding; instead, radical orchiectomy is preferred.

Types of Germ Cell Tumors

Tumor Type	Malignancy	Clinical Features	Key Histology	Prognosis
Seminoma	Malignant	Painless, homogenous enlargement, “fried egg” appearance on histology, elevated PALP	Large cells with watery cytoplasm	Radiosensitive, excellent
Teratoma	May be malignant	Benign in children, malignant in adult males	Mixed mature tissue elements	Variable
Embryonal Carcinoma	Malignant	Painful, hemorrhagic mass, often with necrosis	Glandular or papillary morphology	Worse than seminoma
Yolk Sac Tumor	Malignant	Aggressive, yellow/mucinous, Schiller-Duval bodies	Elevated AFP	Common in boys < 3 years
Choriocarcinoma	Malignant	Hematogenous metastasis, may cause gynecomastia	Syncytiotrophoblasts, cytotrophoblasts	Poor, systemic spread

Sex Cord Stromal Tumors

Sex cord-stromal tumors develop from the embryonic sex cords, which give rise to Sertoli and Leydig cells in the testes. These tumors are rare, generally benign, and account for a small percentage of testicular tumors.

Types of Sex Cord Stromal Tumors

Tumor Type	Malignancy	Clinical Features	Key Histology	Hormonal Effect
Sertoli Cell Tumor	Mostly benign	Often asymptomatic	Androblastoma features	Minimal hormone activity
Leydig Cell Tumor	Mostly benign	Golden-brown color, may cause gynecomastia or precocious puberty	Reinke crystals	Androgens or estrogens
Testicular Lymphoma	Malignant	Most common in older men, usually metastatic	Lymphoid cells	Often systemic symptoms

Important Points to Remember

Germ Cell Tumors: Account for 95% of all testicular tumors and arise from sperm-producing germ cells.
- Risk factors include cryptorchidism and Klinefelter syndrome.
- Typically do not transilluminate and are managed by radical orchiectomy.
Sex Cord Stromal Tumors: Comprise 5% of testicular tumors and are mostly benign.
- Originating from Sertoli and Leydig cells in the seminiferous tubules, they often do not produce significant clinical symptoms.
Diagnostic Approach: Radical orchiectomy is performed instead of biopsy due to risk of tumor seeding. Serum tumor markers (AFP, hCG, PALP) can aid in diagnosis and management.

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