{"entity":{"id":"leydig-cell-tumour","kind":"cancer","name":"Leydig cell tumour of the testis","aka":["Leydig cell tumour","Leydig cell tumor","Interstitial cell tumour of the testis","Malignant Leydig cell tumour"],"tldr":"Leydig cell tumour is the commonest testicular tumour that is not a germ cell tumour; it grows from the hormone-making cells between the seminiferous tubules. It often makes testosterone or oestrogen, causing early puberty in boys or breast growth in men, and about nine in ten are benign and cured by surgery; the malignant minority responds poorly to chemotherapy.","summary":"Leydig cell tumours are sex cord-stromal tumours of the testis, listed in the WHO classification apart from the germ cell tumours that make up most testicular cancer (Moch 2016). They are the most common non-germ cell neoplasms of the testis and are often hormonally active, producing precocious virilisation in boys or feminisation in adults (JCEM 2006). Malignancy, defined by metastasis rather than by histology alone, occurs in up to 10 percent, with large size, necrosis, vascular invasion, atypia and high mitotic count as warning features; the main differential in boys with congenital adrenal hyperplasia is the testicular adrenal rest tumour, which responds to steroid suppression (Avicenna Journal of Medicine 2013). Germline fumarate hydratase mutations, the cause of the HLRCC syndrome, were found in two of 30 adult Leydig cell tumours, with loss of the wild-type allele and activation of the hypoxia pathway (JCEM 2006).\n\nHow it differs from its parent: the testicular page describes germ cell tumours, cured by cisplatin; Leydig cell tumours do not respond to that chemotherapy, do not raise the germ cell markers, and are staged and managed as a sex cord-stromal tumour, with testis-sparing surgery possible for small benign tumours.\n\nHow common: no incidence figure in the sources read.\n\nTreatment: radical or testis-sparing orchidectomy for benign tumours; retroperitoneal lymph node dissection for tumours with malignant features or nodal disease; metastatic disease has no effective chemotherapy and is managed case by case (NCI PDQ testicular summary for the germ cell comparison).","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/Leydig_cell_tumour","links":[{"label":"NCI PDQ: testicular cancer treatment","url":"https://www.cancer.gov/types/testicular/treatment"},{"label":"Moch 2016, European Urology: the 2016 WHO classification of urinary and male genital tumours, part A","url":"https://doi.org/10.1016/j.eururo.2016.02.029"},{"label":"JCEM 2006: adult Leydig cell tumours of the testis caused by germline fumarate hydratase mutations","url":"https://doi.org/10.1210/jc.2006-0183"},{"label":"Avicenna Journal of Medicine 2013: testicular adrenal rest tumour or Leydig cell tumour, case and review","url":"https://doi.org/10.4103/2231-0770.112789"}],"tags":["subtype-page","wave4","testicular","rare"],"related":["testicular","sertoli-cell-tumour","granulosa-cell-tumour","seminoma"],"cancers":[],"sections":[],"technologies":[],"targets":["fh"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"genitourinary","burden":"The most common non-germ cell tumour of the testis (JCEM 2006), yet a small minority of testicular tumours; up to 10 percent behave malignantly (Avicenna Journal of Medicine 2013). No registry figure was found in the sources read.","subtypes":[],"biomarkers":["Inhibin and calretinin positive; germ cell markers negative","Testosterone, oestradiol and gonadotrophins","Size, necrosis, vascular invasion, atypia and mitotic count (malignancy risk)","Fumarate hydratase (rare germline cases)"],"standardOfCare":[{"setting":"All cases","approach":"Orchidectomy (testis-sparing for small benign tumours); retroperitoneal node dissection for malignant features; no effective chemotherapy for metastatic disease.","refs":["testicular"]}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":[],"parent":"testicular"},"route":"/cancers/leydig-cell-tumour/","neighbours":{"cancer":[{"id":"granulosa-cell-tumour","kind":"cancer","name":"Adult granulosa cell tumour of the ovary","route":"/cancers/granulosa-cell-tumour/"},{"id":"seminoma","kind":"cancer","name":"Seminoma","route":"/cancers/seminoma/"},{"id":"sertoli-cell-tumour","kind":"cancer","name":"Sertoli cell tumour of the testis","route":"/cancers/sertoli-cell-tumour/"},{"id":"spermatocytic-tumour","kind":"cancer","name":"Spermatocytic tumour of the testis","route":"/cancers/spermatocytic-tumour/"},{"id":"testicular","kind":"cancer","name":"Testicular germ cell tumours","route":"/cancers/testicular/"}],"target":[{"id":"fh","kind":"target","name":"FH","route":"/targets/fh/"}]}}