Non-germ cell tumours comprise 5% of testicular tumours.
Sex-Cord Stromal Tumours
These contain Leydig, Sertoli, granulosa, or thecal cells. About 90% are benign and 10% malignant — the only reliable criterion for malignancy is metastatic disease (most often to the retroperitoneum and lung).
Leydig Cell Tumours
- Account for 75–80% of sex-cord stromal tumours; most occur in men aged 30–60, with no association with cryptorchidism.
- ~10% are bilateral (more often than GCT) and may cause gynecomastia (as with GCT).
- Radical inguinal orchiectomy is the initial treatment of choice. If suspected preoperatively, the 90% benign rate makes testis-sparing surgery reasonable for lesions <3 cm with intraoperative frozen section; perform completion orchiectomy if GCT histology (frozen or final) or malignant features appear.
- Persistent Leydig dysfunction/hypogonadism may follow excision — 40% require testosterone supplementation.
Sertoli, Granulosa & Gonadoblastoma
- Sertoli cell tumours — like Leydig, TSS is reasonable for tumours <3 cm given ~90% benign histology.
- Granulosa cell tumours — exceedingly rare.
- Gonadoblastoma — occurs almost exclusively with gonadal dysgenesis and intersex syndromes; bilateral orchiectomy is required because of a 40% risk of bilateral tumours.
Miscellaneous Testicular Neoplasms
- Dermoid and epidermoid cysts — "onion-peel" appearance on ultrasound. Enucleation or partial orchiectomy is acceptable, but sample thoroughly to exclude GCT or ITGCN.
- Adenocarcinoma of the rete testis — rare but highly malignant, arising from the testicular collecting system; >50% present with metastasis and median overall survival is ~1 year.
Secondary Tumours
- Lymphoma — usually involves the testis by dissemination from extra-testicular sites; 85% occur in men >60, and non-Hodgkin lymphoma is the most common testicular neoplasm in men >50. Bilateral involvement in 35%. Treat with radical inguinal orchiectomy and refer to hematology-oncology.
- Leukemic infiltration — the testis is a frequent relapse site in boys with acute lymphocytic leukemia. Diagnosis is by biopsy (orchiectomy unnecessary); achieve local control with low-dose radiotherapy that includes the contralateral testis given the frequent bilateral risk.
- Metastases — most common primaries are prostate, lung, melanoma, colon, and kidney.
Tumours of the Testicular Adnexa
- Adenomatoid tumour — the most common paratesticular tumour, usually in the epididymis; asymptomatic and benign (no reported metastasis). Management: surgical excision.
- Cystadenoma — ~1/3 occur in von Hippel-Lindau disease and are usually bilateral.
- Paratesticular mesothelioma — arises from the tunica vaginalis.
- Sarcomas (spermatic cord, epididymis, testis) — the most common genitourinary sarcomas in adults; liposarcoma is the most common subtype in adults, and embryonal rhabdomyosarcoma is most common in men <30. Manage with wide resection via an inguinal approach (excise the testis and spermatic cord with high ligation), adding therapy by subtype and metastatic status. Liposarcomas rarely metastasize but recur locally — consider adjuvant radiotherapy (especially with positive margins or large tumours). With a normal metastatic workup, non-liposarcoma sarcomas (rhabdomyosarcoma, malignant fibrous histiocytoma, angiosarcoma) and mesothelioma warrant RPLND, with postoperative chemotherapy if retroperitoneal nodes are involved.
Self-Test
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What is the only reliable criterion for malignancy in a sex-cord stromal tumour? The presence of metastatic disease (most often retroperitoneum or lung) — histology alone cannot establish it.
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When can testis-sparing surgery be considered for a Leydig or Sertoli cell tumour? For lesions <3 cm with intraoperative frozen-section confirmation, given ~90% benign histology; convert to completion orchiectomy for GCT or malignant features.
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What is the most common testicular neoplasm in men over 50? Non-Hodgkin lymphoma — usually by secondary dissemination, bilateral in 35%, treated with orchiectomy plus hematology-oncology referral.
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Why is bilateral orchiectomy required for gonadoblastoma? There is a 40% risk of bilateral tumours; it arises almost exclusively in gonadal dysgenesis/intersex syndromes.
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What is the most common paratesticular adnexal tumour, and how is it managed? Adenomatoid tumour (usually epididymal, benign) — managed by surgical excision.