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Testosterone Treatment for Anorchia and Micropenis in Infancy« Back to Volume 23, Issue 2, June 2007 - Table of Contents Bilateral anorchia in a phenotypically normal XY male is a rare condition diagnosed at birth or in infancy. It is defined as the absence of testicular functioning structures; it is generally accepted that it is consistent with a late testosterone deficiency, after normal male genital differentiation has occurred. The precise etiology (mechanism), except for neonatal testicular torsion with intragonadal hemorrhage, is unknown. The frequency and significance of associated micropenis has not been evaluated. This multicenter study evaluated the effect of testosterone treatment on the penile length before puberty. Fifty-five boys with bilateral anorchia were studied at a mean chronological age of 2.5 years. Subjects were divided into 2 groups according to the clinical scrotal findings: group A had no palpable testis (n=29) and group B had unilateral or bilateral scrotal mass (n=26). Karyotype was normal in 46 out of 48 cases. In 33 children surgery was performed with histological analysis. Anorchia diagnosis was also based on classical endocrine criteria, including plasma anti-mullerian hormone (AMH) levels and hCG stimulation tests. A micropenis (length <−2 SD for age) was present in 46% of patients in both groups. A mechanical etiology was likely in 2 boys in group A and in 3 boys of group B when hemorrhagic testis were observed at histology, likely relating to perinatal testicular torsion. Interestingly, the penile length in these 5 cases was significantly greater than in the other patients with unknown etiology. Prepubertal treatment with prolonged testosterone stimulation was administered to 19 boys (mean age 0.7 months). The penile length increased from a mean length of −2.8 SD to −0.8 SD at the end of the treatment, and −1 SD 3 months later. In 6 patients the penile length remained <−2 SD, regardless of the dose of testosterone treatment. The presence of isolated micropenis in almost half of the patients with bilateral anorchia strongly suggests that the testicular alteration occurred during late gestation after male sex differentiation. In most cases treatment with testosterone stimulated penile growth. The authors favour the hypothesis that, in some patients, an intrinsic endocrine disorder may cause bilateral anorchia, after a long period of normal fetal endocrine functioning. Zenaty D, Dijoud F, Morel Y, et al. Bilateral anorchia in infancy: occurrence of micropenis and the effect of testosterone treatment. J Pediatr. 2006;149:687–91. Editor’s CommentThis condition has been well described by Aynsley-Green et al as bilateral anorchia.1 Others have suggested the concept of “vanishing testis”2 or embryonic testicular regression.3 The authors suggested that anorchia may be part of the spectrum of 46 XY gonadal dysgenesis; this may be supported by previously reported 3 familial cases, some combining sexual differentiation alterations in members of the same family. Clearly, further investigation will be necessary, with more recently described transcription factors involved in testicular differentiation. From a clinical point of view this report provides useful information on the effect of long-acting testosterone treatment. It appears that all except 3 boys of group A responded to testosterone treatment with 3 to 4 injections at a dose 50 to 150 mg/m2 per injection every 2 to 4 weeks. In a previous study the authors had shown that repeating the treatment during infancy did not improve gain in penile growth.4 Currently, we are lacking information on the outcome during puberty. There is a possibility that there may be a partial resistance to testosterone, whether due to inappropriate timing in the penis stimulation before birth or to a genetic defect inducing androgen resistance. This study, as well as previous reports, confirms that early treatment with testosterone is necessary; a course of therapy for 2 to 4 months per protocol is generally sufficient and well tolerated. Unfortunately, full correction of the penile length cannot be accomplished in all cases. When testosterone replacement therapy is given, further follow-up until puberty is required to assess anatomical and functional development of the penis. Raphaël Rappaport , MD References - (linked to
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Volume 26 Number 1
September 2010
www.GGHjournal.com
ISSN 1932-9032
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