Department of Growth and Pediatric Endocrinology, Hirabai Cowasji Jehangir Medical Research Institute, Block V Lower Basement, Jehangir Hospital, 32 Sassoon Road, Pune, Maharashtra, 411001, India.
Interdisciplinary School of Health Sciences, Savitribai Phule University, Pune, India.
Indian J Pediatr. 2023 Jun;90(6):598-604. doi: 10.1007/s12098-023-04540-w. Epub 2023 Apr 20.
Micropenis, i.e., a structurally normal but abnormally small penis is defined as stretched penile length (SPL) 2.5 SD below the mean for age and sexual stage. Several studies worldwide have published country-specific normative data on SPL; an appropriate cutoff for evaluation of micropenis as per international standards would be below 2 cm at birth and below 4 cm after 5 y of age. Testosterone production by fetal testes, its conversion to dihydrotestosterone (DHT) and its action on the androgen receptor is necessary for normal penile development. Hypothalamo-pituitary disorders (gonadotropin or growth hormone deficiencies), genetic syndromes, partial gonadal dysgenesis, testicular regression, disorders of testosterone biosynthesis and action constitute the various etiologies of micropenis. Associated hypospadias, incomplete scrotal fusion, and cryptorchidism are suggestive of disorders of sex development (DSD). Along with basal and human chorionic gonadotropins (HCG)-stimulated gonadotropins, testosterone, DHT, and androstenedione levels, karyotype assessment is equally important. Treatment aims at attaining penile length sufficient enough for urination and to perform sexual function. Hormonal therapy with intramuscular or topical testosterone, topical DHT or recombinant follicle stimulating hormone (FSH) and luteinizing hormone (LH) should be attempted in the neonatal or infancy period. The role of surgery for micropenis is limited and has variable patient satisfaction and complication outcomes. There is a need for long-term studies on the adult SPL achieved following treatment for micropenis in infancy and childhood.
小阴茎是指结构正常但明显短小的阴茎，其定义为伸展阴茎长度（SPL）低于年龄和性发育阶段平均值的 2.5 个标准差。全球有几项研究发表了特定国家/地区的 SPL 正常参考值数据；根据国际标准，评估小阴茎的适当临界值为出生时低于 2 厘米，5 岁后低于 4 厘米。胎儿睾丸产生的睾酮、其向二氢睾酮（DHT）的转化及其对雄激素受体的作用对于正常阴茎发育是必需的。下丘脑-垂体功能障碍（促性腺激素或生长激素缺乏）、遗传综合征、部分性腺发育不全、睾丸退化、睾酮生物合成和作用障碍构成了小阴茎的各种病因。伴有尿道下裂、不完全阴囊融合和隐睾提示性发育障碍（DSD）。除了基础和人绒毛膜促性腺激素（HCG）刺激的促性腺激素、睾酮、DHT 和雄烯二酮水平外，核型评估同样重要。治疗旨在获得足够的阴茎长度，以满足排尿和进行性功能的需求。在新生儿或婴儿期应尝试肌内或局部注射睾酮、局部 DHT 或重组卵泡刺激素（FSH）和黄体生成素（LH）进行激素治疗。手术治疗小阴茎的作用有限，且患者满意度和并发症结局存在差异。需要对婴儿期和儿童期治疗后获得的成年 SPL 进行长期研究。
