- Human pathology

Home > E. Pathology by systems > Reproductive system > Male genital system > Testis > testicular Leydig cell tumor

testicular Leydig cell tumor

Friday 9 January 2015

Leydig cell tumor of the testis

Leydig cell tumors of the testis are rare and account for a small proportion of testicular neoplasms. Most patients (93%) had a testicular mass.

Digital cases

- HPC:119 : Leydig cell tumor.
- JRC:18782 : Testis intestitial cell tumor


- Leydig cell tumor of the testis


Patients with Leydig cell tumors that metastasized are diagnosed at a mean age of 62 years (range, 39-70 years) compared with 48 years (range, 9-79 years) in patients with non-metastasizing tumors (p = 0.25).

Leydig cell tumors that metastasized were significantly larger than nonmetastasizing tumors (mean, 4.7 versus 2.6 cm, respectively; p = 0.008), and had a significantly higher mitotic index (mean, 13.9 versus 1.9, respectively; p @<@ 0.0001).

Metastasizing Leydig cell tumors were significantly associated with atypical mitotic figures (p @<@ 0.0001), nuclear variation (p = 0.0025), necrosis (p @<@ 0.0001), angiolymphatic invasion (p = 0.009), infiltrative margins (p @<@ 0.0001), high grade (p = 0.0004), and invasion into rete testis, epididymis, or tunica (p = 0.001) when compared with non-metastasizing tumors.

There was no significant difference between metastasizing and nonmetastasizing tumors in regard to cell type, lipochrome content, presence of Reinke crystals, or nuclear inclusions.

All Leydig cell tumors that metastasized and 7 of 18 (38.9%) non-metastasizing tumors were DNA aneuploid by static image analysis (p = 0.02).

Metastasizing Leydig cell tumors had a significantly higher mean MIB-1 activity of 18.6% (range, 5.8-33.6) compared with 1.2% (range, 0.04-8.2) in non-metastasizing tumors (p = 0.001).

In a study, the presence of cytologic atypia, necrosis, angiolymphatic invasion, increased mitotic activity, atypical mitotic figures, infiltrative margins, extension beyond the testicular parenchyma, DNA aneuploidy, and increased MIB-1 activity were significantly associated with metastatic behavior in Leydig cell tumors. (9808128)


- Leydig cell proliferation

  • round cell proliferation
  • fusiform cell proliferation

- Leydig cells

  • abundant eosinophilic cytoplasm
  • characteristic nuclear-rich zones separated by nuclear-free zones
  • crystals of Reinke (Reinke crystals)

Other localization

- ovarian Leydig cell tumor
- paratesticular Leydig cell tumor


- microcystic Leydig cell tumor (10328086)

Differential diagnosis

- yolk sac tumor (10328086)

See also

- Sertoli-stromal cell tumors


- Billings SD, Roth LM, Ulbright TM. Microcystic Leydig cell tumors mimicking yolk sac tumor: a report of four cases. Am J Surg Pathol. 1999 May;23(5):546-51. PMID: 10328086

- Leydig cell tumor of the testis: a clinicopathologic, DNA content, and MIB-1 comparison of nonmetastasizing and metastasizing tumors. Cheville JC, Sebo TJ, Lager DJ, Bostwick DG, Farrow GM. Am J Surg Pathol. 1998 Nov;22(11):1361-7. PMID: 9808128