[Leydig cell hyperplasia of testis in children: a clinicopathological study].

To investigate the clinical, pathological features and differential diagnosis of testicular Leydig cell hyperplasia (LCH) . Clinical data, histological features, immunohistochemical findings, ultrastructural characteristics and follow-up data were analyzed in three cases of LCH. The cases were collected from 2011 to 2014 at Beijing Children's Hospital. A literature review was performed. Two males (1.8 years and 2.9 years of age) showed isosexual pseudoprecocity with elevated serum testosterone. Imaging study showed bilateral testicular enlargement with multiple small nodules in the parenchyma. Another 13 years-old patient showed male pseudohermaphroditism and cryptorchism. Gross examination showed the bilateral markedly enlarged testis without discrete lesion. Histologically, LCH was seen in both nodular and diffuse patterns without destruction of seminiferous tubules. Adjacent spermatogenesis was noted. Immunohistochemically, the Leydig cells were positive for inhibin, calretinin and Melan A and ultrastructural analysis showed enriched cytoplasmic endoplasmic reticulum. Two cases had followed up for 7 years. One patient was symptom-free and one was stable. LCH is a rare benign condition, which is easily misinterpreted as testicular tumor or non-neoplastic diseases. Clinical presentation, imaging study and pathological evaluation are required for the diagnosis.