Sertoli Cell Tumour of the Testis

Sertoli cell tumour is a rare sex cord stromal tumour of the testis, making up under 1% of testicular tumours. It arises from the supporting Sertoli cells.

Three forms are recognised: classic (not otherwise specified), large cell calcifying, and sclerosing. It occurs at any age, with a peak in men aged 20 to 45, and the large cell calcifying form arises in children and young adults.

Most are benign, and about 10 to 20% of the classic type are malignant.

Pathophysiology. Tumour cells form tubules and cords and may secrete oestrogens, inhibin and anti-Müllerian hormone. Hormone effects produce gynaecomastia in a minority.

Malignant features:

• Size over 5 cm, infiltrative margins and necrosis.
• Vascular invasion, nuclear atypia, and over 5 mitoses in 10 high power fields.
• Age over 50 and extension beyond the testis.

Syndromic associations of the large cell calcifying form: Carney complex (PRKAR1A mutations, with myxomas, skin lentigines, endocrine overactivity) and Peutz-Jeghers syndrome (STK11). These cases are often bilateral and multifocal.

A painless, firm testicular mass or incidental nodule. Gynaecomastia in about 20 to 25%, and in children precocious puberty or growth acceleration in some. Syndromic cases show lentigines, cardiac myxoma (palpitations, embolic events), pituitary and thyroid disease, and gastrointestinal polyps. Retroperitoneal nodes or distant metastasis indicate malignant disease.

• Scrotal ultrasound: a well defined, hypoechoic or heterogeneous mass, with coarse calcifications in the large cell calcifying type, and often hypervascularity.
• MRI of the scrotum when needed.
• AFP, beta-hCG and lactate dehydrogenase to exclude germ cell tumour. Inhibin B, oestradiol, testosterone, LH and FSH.
• Staging by CT of chest, abdomen and pelvis when malignant features are present.
• In large cell calcifying tumours: echocardiography, thyroid ultrasound, pituitary hormones (IGF-1, prolactin), and genetic testing for PRKAR1A and STK11. Look for adrenal disease and skin lesions.
• Histology after orchidectomy or enucleation: inhibin, calretinin, SF-1 and vimentin positive, with OCT3/4 and placental alkaline phosphatase negative.

Differential diagnosis.

• Leydig cell tumour
• Seminoma and other germ cell tumours
• Testicular adrenal rest tumour
• Granulosa cell tumour
• Testicular lymphoma
• Calcified scar or burned out tumour

• Radical inguinal orchidectomy with high ligation of the cord for most adults.
• Testis sparing enucleation for small, benign looking lesions, for bilateral or syndromic tumours, or in children, directed by frozen section.
• Sperm banking before surgery in men who want children.
• Malignant tumour:
  • Retroperitoneal lymph node dissection for limited nodal disease.
  • Chemotherapy and radiotherapy have poor response. Platinum based regimens have been used in metastatic disease, within a specialist centre.
• Syndromic disease: screen and treat Carney complex (surgical removal of cardiac myxoma, endocrine care) and Peutz-Jeghers complications, with genetic counselling.
• Gynaecomastia after surgery: tamoxifen 20 mg orally daily for 3 to 6 months when early and painful, or surgery.
• Hypogonadism: testosterone replacement with gel 50 mg daily or testosterone undecanoate 1000 mg intramuscularly every 10 to 14 weeks after loading.

Special groups. Children need testis sparing surgery when the lesion is benign, with paediatric oncology and endocrinology. Carney complex needs echocardiography every 1 to 2 years.

Monitoring. Benign tumour: ultrasound and hormones at 3 months and yearly. Malignant features: clinical review, markers and CT every 3 to 6 months for 2 years, then yearly for at least 5 years.

Referral and escalation. Refer to urology, with oncology for malignant features and genetics for syndromic disease. Urgent referral for a palpable mass or metastasis.