Clomiphene Citrate for Men with Hypogonadism - A Systematic Review & Meta-analysis

Safety assessment of clomiphene: a real-world pharmacovigilance analysis from the Food and Drug Administration adverse event reporting system

BACKGROUND

Clomiphene is widely used for the treatment of anovulatory infertility, yet there remain many unrecognized adverse events (AEs). The objective of this study is to provide a comprehensive overview of the safety profile of clomiphene.

METHODS

The data were derived from the first quarter of 2004 to the third quarter of 2023 from the Food and Drug Administration Adverse Event Reporting System (FAERS) database. The detection of new AE signals involved the use of four algorithms: reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and empirical Bayesian geometric mean (EBGM).

RESULTS

A total of 16,677,289 AE reports were acquired from the FAERS database, and there were 2,620 AEs specifically reported in 720 patients following clomiphene use. The AEs encompassed 102 preferred terms (PTs) across 24 system organ classes (SOCs). Some new AEs were identified, including conjoined twins (0.5%), Potter's syndrome (0.3%), genitalia external ambiguous (0.3%), esophageal atresia (0.6%), and anal atresia (0.3%).

CONCLUSIONS

Although the majority of AEs aligned with the drug instruction, some new AE signals such as conjoined twins and genitalia external ambiguous were not captured. Well-designed studies are required to demonstrate the safety of clomiphene.

Diagnosis and treatment of hypogonadism in men seeking to preserve fertility - what are the options?

Male hypogonadism is a clinical syndrome that results in low testosterone levels and frequently leads to infertility. The syndrome occurs due to disruption at one or more levels of the hypothalamic-pituitary-gonadal axis. Testosterone replacement therapy (TRT) is the most common treatment utilised for male hypogonadism. However, long-acting forms of TRT leads to infertility and so is inappropriate for patients wishing to conceive. For patients who wish to remain fertile, nasal TRT, clomiphene citrate, exogenous gonadotropins, gonadotropin releasing hormone and aromatase inhibitors have been used as alternative treatment options with different degrees of success. A review of the literature was performed to identify the safety and efficacy of alternative treatment options. Gonadotropin releasing hormone can successfully induce spermatogenesis but is impractical to administer. Likewise, aromatase inhibitors have limited use due to inducing osteopenia. Nasal TRT may be a good treatment option for these patients, but its efficacy has so far only been demonstrated in small sample sizes. However, clomiphene citrate and exogenous gonadotropins are safe, offer good symptom control and can successfully induce fertility in hypogonadism patients.

Long-term use of clomiphene in male macroprolactinomas with persistent hypogonadism

BACKGROUND

Men with macroprolactinoma can present persistent hypogonadism despite normoprolactinemia achieved with clinical and/or neurosurgical treatment. Usually, testosterone replacement therapy is indicated. Nevertheless, although off-label, clomiphene citrate (CC), a selective estrogen receptor modulator, has also been used, mainly when fertility is an issue. The aim of this study is to evaluate the effectiveness of CC in recovering the gonadal axis in men with macroprolactinoma, with or without hyperprolactinemia, and evaluate its safety as a long-term therapy.

METHODS

This is a retrospective study including 10 men with macroprolactinoma on cabergoline treatment and persistent hypogonadism. All patients received initially 50 mg/d of CC.

RESULTS

The median age at diagnosis of prolactinomas was 34 (range, 26-60) years old. All patients were treated with cabergoline at a median maximum dose of 2 (1-7) mg/week, with a median time of treatment of 8.5 (2-15) years. Prolactin was still above the normal range when CC was introduced only in two patients. The mean duration of CC therapy was 3.2 (±2.8) years. Prolactin levels maintained stable (p = 0.252) and testosterone increased (p = 0.027) significantly on CC therapy. Tumor size remained stable. Eight patients (80%) maintained testosterone above 300 ng/dL and were classified as responders. Three responders succeeded in using a lower dose of CC and one of them completed withdrawal CC and maintained eugonadism. There were no side effects or safety concerns reported.

CONCLUSION

CC should be seen as a safe treatment option for men with macroprolactinoma and persistent hypogonadism.

Urinary concentrations of bisphenol A, parabens and benzophenone-type ultra violet light filters in relation to sperm DNA fragmentation in young men: A chemical mixtures approach

People are daily exposed to multiple endocrine disruptor compounds (EDCs) that may interfere with different molecular and cellular processes, promoting a potential estrogenic, androgenic, or anti-androgenic state. However, most epidemiological studies attempting to establish relationships between EDCs exposure and health effects are still considering individual compounds. A few studies have shown associations between exposure to individual non-persistent EDCs and sperm DNA fragmentation (SDF) in different male populations. Thus, the aim of this study was to investigate associations between combined exposure to non-persistent EDCs and SDF index in young men. A cross-sectional study was conducted with 158 healthy university students from Southeaster Spain. The participants provided spot urine and semen samples on the same day. The concentrations of urinary bisphenol A (BPA), benzophenones [2,4-dihydroxybenzophenone (BP-1); 2,2',4,4'-tetrahydroxybenzophenone (BP-2), 2-hydroxy-4-methoxybenzophenone (BP-3), 2,2'-dihydroxy-4-methoxybenzophenone (BP-8), 4-hydroxybenzophenone (4OHBP)], and parabens (methylparaben, ethylparaben, propylparaben, butylparaben) were measured by dispersive liquid-liquid microextraction and ultrahigh-performance liquid chromatography with tandem mass spectrometry detection. SDF was analysed using a Sperm Chromatin Dispersion test. Statistical analyses were carried out using Bayesian Kernel Machine Regression models to evaluate associations between combined exposure to these compounds and SDF index while adjusting by relevant covariates. The increase in urinary concentration of 4OHBP was found to be the most important contributor to the negative association between urinary EDCs concentrations and SDF index, being of -5.5 % [95 % CI: -10.7, -0.3] for those in percentile 50, and - 5.4 % [95 % CI: -10.8, -0.1] for those in percentile 75. No significant associations were observed between other EDCs and SDF index. Our findings show that urinary 4OHBP levels may be associated with a decrease in the SDF index. Nonetheless, the effects we observed were likely to be small and of uncertain clinical significance. Further research is needed to replicate our findings in other male populations.

Management of Male Fertility in Hypogonadal Patients on Testosterone Replacement Therapy

Testosterone is crucial in regulating several body functions in men, including metabolic, sexual, and cardiovascular functions, bone and muscle mass, and mental health. Therefore, optimizing testosterone levels in men is an important step to maintaining a healthy body and mind, especially as we age. However, traditional testosterone replacement therapy has been shown to lead to male infertility, caused by negative feedback in the hypothalamic-pituitary-gonadal (HPG) axis. Recent advances in research have led to the discovery of many new methods of administration, which can have more or less suppressive effects on the HPG axis. Also, the usage of ancillary medications instead of or after testosterone administration might help maintain fertility in hypogonadal patients. The goal of this narrative review is to summarize the newest methods for optimizing fertility parameters in patients undergoing treatment for hypogonadism and to provide the necessary information for healthcare providers to make the right treatment choices.

Effect of oestrogen modulation on semen parameters in men with secondary hypogonadism: Systematic review and meta-analysis

BACKGROUND

Selective oestrogen receptor modulators and aromatase inhibitors stimulate endogenous gonadotrophins and testosterone in men with hypogonadism. There are no systematic reviews/meta-analyses assessing the effects of selective oestrogen receptor modulators/aromatase inhibitors on semen parameters in men with secondary hypogonadism.

OBJECTIVES

To assess the effect of monotherapy or a combination of selective oestrogen receptor modulators/aromatase inhibitors on sperm parameters and/or fertility in men with secondary hypogonadism.

MATERIALS AND METHODS

A systematic search was conducted in PubMed, MEDLINE, Cochrane Library and ClinicalTrials.gov. Study selection and data extraction were performed by two reviewers independently. Randomised controlled trials and non-randomised studies of interventions reporting effects of selective oestrogen receptor modulators and/or aromatase inhibitors on semen parameters or fertility in men with low testosterone with low/normal gonadotrophins were selected. The risk of bias was assessed using ROB-2 and ROBINS-I tools. The results of randomised controlled trials were summarised using vote counting while summarising effect estimates where available. Non-randomised studies of intervention meta-analysis were conducted using the random-effect model. The certainty of evidence was assessed using GRADE.

RESULTS

Five non-randomised studies of interventions (n = 105) of selective oestrogen receptor modulators showed an increase in sperm concentration (pooled mean difference 6.64 million/mL; 95% confidence interval 1.54, 11.74, I2  = 0%) and three non-randomised studies of interventions (n = 83) of selective oestrogen receptor modulators showed an increase in total motile sperm count (pooled mean difference 10.52; 95% confidence interval 1.46-19.59, I2  = 0%), with very low certainty of evidence. The mean body mass index of participants was >30 kg/m2 . Four randomised controlled trials (n = 591) comparing selective oestrogen receptor modulators to placebo showed a heterogeneous effect on sperm concentration. Three included men with overweight or obesity. The results were of very low certainty of evidence. Limited pregnancy or live birth data were available. No studies comparing aromatase inhibitors with placebo or testosterone were found.

DISCUSSION AND CONCLUSION

Current studies are of limited size and quality but suggest that selective oestrogen receptor modulators may improve semen parameters in those patients, particularly when associated with obesity.

Factors predicting normalization of reproductive hormones after cessation of anabolic-androgenic steroids in men: a single center retrospective study

OBJECTIVE

Symptomatic hypogonadism discourages men from stopping anabolic-androgenic steroids (AAS). Some men illicitly take drugs temporarily stimulating endogenous testosterone following AAS cessation (post-cycle therapy; PCT) to lessen hypogonadal symptoms. We investigated whether prior PCT use was associated with the normalization of reproductive hormones following AAS cessation.

METHODS

Retrospective analysis of 641 men attending a clinic between 2015-2022 for a single, nonfasting, random blood test <36 months following AAS cessation, with or without PCT. Normalized reproductive hormones (ie, a combination of reference range serum luteinizing hormone, follicle-stimulating hormone, and total testosterone levels) were the surrogate marker of biochemical recovery.

RESULTS

Normalization of reproductive hormones was achieved in 48.2% of men. PCT use was associated with faster biochemical recovery (13.0 (IQR8.0-19.0) weeks, PCT; 26.0 (IQR10.5-52) weeks, no-PCT; P < .001). Odds of biochemical recovery during multivariable analysis were: (1) higher with PCT (OR3.80) vs no-PCT (P = .001), in men stopping AAS ≤3 months previously; (2) reduced when 2 (OR0.55), 3 (OR0.46), or 4 (OR0.25) AAS were administered vs 1 drug (P = .009); (3) lower with AAS >6 vs ≤3 months previously (OR0.34, P = .01); (4) higher with last reported AAS >3 months (OR 5.68) vs ≤3 months (P = .001). PCT use was not associated with biochemical recovery in men stopping AAS >3 months previously.

CONCLUSION

Without evidence-based withdrawal protocols, men commonly try avoiding post-AAS hypogonadism with PCT, which is illicit, ill-defined, and not recommended. Only half of men had complete biochemical testicular recovery after stopping AAS. The surprising association of self-reported PCT use with short-term biochemical recovery from AAS-induced hypogonadism warrants further investigation.

The use of post-cycle therapy is associated with reduced withdrawal symptoms from anabolic-androgenic steroid use: a survey of 470 men

BACKGROUND

Anabolic-androgenic steroids (AAS) mimic the effects of testosterone and may include testosterone itself; they are used for body enhancement within the general population. AAS use has been linked with increased mortality, cardiovascular disease, mental health disorders, and infertility. AAS-induced hypogonadism can persist for an uncertain time period despite cessation, during which men may report physical and neuropsychiatric symptoms. In an attempt to mitigate these symptoms and expedite testicular recovery, many men self-administer post-cycle-therapy (PCT), typically involving human chorionic gonadotrophin (hCG) and selective oestrogen receptor modulators (SERMs), which are known to potently stimulate testicular function. However, this practice has no objective evidence of effectiveness to lessen the severity or duration of hypogonadal symptoms.

METHODS

An anonymous survey of four-hundred-and-seventy men using AAS explored the symptoms they experienced when ceasing AAS use; the effect of PCT on relieving their symptoms, and their perceived role for health service support.

RESULTS

The majority of respondents were white, aged 18-30 years old, and working in skilled manual work. 51.7% (n = 243) reported no issues with AAS use, but 35.3% reported increased aggression. 65.1% (n = 306) of respondents had attempted AAS cessation and 95.1% of these experienced at least one symptom upon AAS cessation. Low mood, tiredness and reduced libido were reported in 72.9%, 58.5% and 57.0% of men stopping AAS use, respectively, with only 4.9% reporting no symptoms. PCT had been used by 56.5% of respondents with AAS cessation and mitigated cravings to restart AAS use, withdrawal symptoms and suicidal thoughts by 60%, 60% and 50%, respectively. The effect of stopping AAS on body composition and recovery of testosterone or fertility was a concern in 60.5% and 52.4%, respectively. Most respondents felt PCT should be prescribed under medical supervision in the community.

CONCLUSIONS

Our survey suggests that the majority of men stopping AAS use are using some form of PCT. Some self-reported symptoms of AAS-induced hypogonadism such as cravings to restart AAS use reduce by 60% and suicidal thoughts reduce by 50%. These individuals are concerned about the negative effect of AAS use and cessation. This study provides crucial information for planning future research to evaluate the effects of PCT on symptoms when men stop AAS use.

Clomiphene citrate for male infertility: A systematic review and meta-analysis

BACKGROUND

Male infertility is a prevalent and worldwide problem with various difficulties in treatment. Clomiphene citrate is a selective estrogen receptor modulator and may improve semen quality by stimulating hormone synthesis and spermatogenesis. There is lack of evidence on the efficacy of clomiphene citrate as therapy for male infertility.

OBJECTIVES

Therefore, a systematic review and meta-analysis was performed to assess the efficacy of clomiphene citrate on sperm quality in infertile men.

METHODS

A search was conducted in the PubMed, EMBASE and Cochrane databases for effectiveness in infertile males treated with clomiphene citrate. Both intervention and observational studies were included. Primary outcome measures were semen parameters (concentration, motility and morphology). Secondary outcomes included hormonal evaluation, pregnancy rate and side effects. Studies were included for meta-analysis if they provided absolute numbers for outcomes before and during treatment with appropriate SD or SE.

RESULTS

Total 1799 studies were identified during the search, 18 studies remained for qualitative analysis (n = 731) and 15 studies for meta-analysis (n = 566). Study populations ranged between 11 and 140 participants. Sperm concentration was higher during treatment, with a mean difference 8.38 × 106 /ml (95% confidence interval: 5.17-11.59; p < 0.00001; I2  = 87%). Total sperm motility was higher during treatment, with a mean difference of 8.14% (95% confidence interval: 3.83-12.45; p < 0.00001; I2  = 76%). There was no difference in sperm morphology before and during treatment. Total testosterone, follicle-stimulating hormone, luteinizing hormone and estradiol were higher during clomiphene citrate treatment. During follow-up, no serious adverse effects occurred. In 10 studies, pregnancy rate was reported and yielded a mean of 17% during clomiphene citrate treatment (range: 0%-40%).

CONCLUSIONS

Clomiphene citrate increased sperm concentration and motility and could be considered as a safe therapy for improving sperm parameters in infertile males.

Synergistic Action of Virgin Coconut Oil and Clomiphene in Reversing Endocrine Dysregulation in Letrozole-Model of Polycystic Ovarian Syndrome in Rats: Role of Nrf2/HMOX-1 Pathway

Polycystic ovarian syndrome (PCOS) is an endocrine disorder in women's reproductive age. Currently, the pathophysiology of PCOS is unclear, and the limited treatment options are unsatisfactory. Virgin coconut oil (VCO) is functional food oil associated with pharmacological effects in reproductive disorders. Therefore, we aimed to evaluate whether VCO could enhance clomiphene (CLO) therapy against PCOS in female rats. Rats were randomly divided: (1) Control, (2) PCOS model, (3) PCOS + CLO, (4) PCOS + VCO, and (5) PCOS + CLO + VCO. The PCOS was induced via daily letrozole (1 mg/kg, orally) administration for 21 days. After the PCOS induction, CLO, VCO, and CLO + VCO were administered from days 22 to 36. Serum levels of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estrogen, progesterone, and prolactin were estimated. Polymerase chain reaction gene expression for nuclear factor-erythroid-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), catalase (CAT), glutathione reductase (GSR), LH receptor (LHr), androgen receptor (AR), tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and caspase-3 were analyzed. The letrozole-induced PCOS caused considerable increases in GnRH, LH, prolactin, estrogen, and testosterone, whereas FSH decreased significantly compared to the control. The gene expression of Nrf2, HO-1, CAT, and GSR were markedly diminished, while IL-1β, TNF-α, caspase-3, AR, and LHr prominently increased compared to control. Interestingly, the CLO and VCO separately exerted anti-inflammatory and endocrine balance effects. However, VCO-enhanced CLO effect in LH, prolactin and testosterone, Nrf2, HO-1, CAT, GSR, and AR. VCO may synergize with CLO to depress hyperandrogenism and oxidative inflammation in PCOS.

Selective modulation of estrogen receptor in obese men with androgen deficiency: A systematic review and meta-analysis

BACKGROUND

Although selective estrogen receptor modulators have been proposed as a treatment for men with central functional hypogonadism, only a few data have been produced in men with obesity-related functional androgen deficiency.

OBJECTIVE

To determine whether and to what extent selective estrogen receptor modulators are an effective and safe therapy in men with obesity-related functional androgen deficiency.

MATERIALS AND METHODS

A thorough search of PubMed, Web of Science, Scopus, and Cochrane Library databases was performed to identify studies comparing testosterone levels before and after treatment. Mean differences with 95% coefficient intervals were combined using random effects models. Funnel plot, Egger's test, and trim-and-fill analysis were used to assess publication bias.

RESULTS

Seven studies met the inclusion criteria providing information on 292 men with obesity-related functional androgen deficiency treated with clomiphene citrate (12.5-50 mg daily) or enclomiphene citrate (12.5-25 mg daily) for 1.5-4 months. The pooled estimates indicated a significant increase in testosterone levels both with clomiphene (mean difference: 11.56 nmol/L; 95% coefficient interval: 9.68, 13.43; I2  = 69%, pfor heterogeneity  = 0.01) and enclomiphene citrate (mean difference: 7.50 nmol/L; 95% coefficient interval: 6.52, 8.48; I2  = 4%, pfor heterogeneity  = 0.37). After the exclusion of one study on severely obese men, who exhibited the highest response rate to clomiphene citrate, the heterogeneity disappeared (mean difference: 10.27 nmol/L; 95% coefficient interval: 9.39, 11.16; I2  = 0%, pfor heterogeneity  = 0.66). No publication bias was revealed by Egger's test and trim-and-fill analysis. No treatment-related unexpected findings regarding safety profile were registered.

DISCUSSION AND CONCLUSION

Treatment with clomiphene citrate and enclomiphene citrate may be an effective and safe alternative to testosterone replacement therapy in men with obesity-related functional androgen deficiency. Further long-term studies are warranted to define clinical reflections of the selective estrogen receptor modulators-induced increase in testosterone levels and to better clarify the safety profile.

Reproductive axis ageing and fertility in men

Compared to women, increasing male age is not accompanied by such marked changes in reproductive function but changes certainly do happen. These include alterations to the hypothalamo-pituitary-testicular axis, with resultant implications for testosterone production and bioavailability as well as spermatogenesis. There is a decline in sexual function as men age, with a dramatic increase in the prevalence of erectile dysfunction after the age of 40, which is a marker for both clinically evident as well as covert coronary artery disease. Despite a quantitative decline in spermatogenesis and reduced fecundability, the male potential for fertility persists throughout adult life, however there are also increasingly recognised alterations in sperm quality and function with significant implications for offspring health. These changes are relevant to both natural and medically assisted conception.

Considerations when treating male pubertal delay pharmacologically

INTRODUCTION

Delayed puberty, defined as the appearance of pubertal signs after the age of 14 years in males, usually affects psychosocial well-being. Patients and their parents show concern about genital development and stature. The condition is transient in most of the patients; nonetheless, the opportunity should not be missed to diagnose an underlying illness.

AREAS COVERED

The aetiologies of pubertal delay in males and their specific pharmacological therapies are discussed in this review.

EXPERT OPINION

High-quality evidence addressing the best pharmacological therapy approach for each aetiology of delayed puberty in males is scarce, and most of the current practice is based on small case series or unpublished experience. Male teenagers seeking attention for pubertal delay most probably benefit from medical treatment to avoid psychosocial distress. While watchful waiting is appropriate in 12- to 14-year-old boys when constitutional delay of growth and puberty (CGDP) is suspected, hormone replacement should not be delayed beyond the age of 14 years in order to avoid impairing height potential and peak bone mass. When primary or central hypogonadism is diagnosed, hormone replacement should be proposed by the age of 12 years provided that a functional central hypogonadism has been ruled out. Testosterone replacement regimens have been used for decades and are fairly standardised. Aromatase inhibitors have arisen as an interesting alternative for boy with CDGP and short stature. Gonadotrophin therapy seems more physiological in patients with central hypogonadism, but its relative efficacy and most adequate timing still need to be established.

Efficacy and Safety of Human Chorionic Gonadotropin Monotherapy for Men With Hypogonadal Symptoms and Normal Testosterone

Background

Male hypogonadism has a prevalence of about 6% and is defined by two-morning testosterone levels below 300 ng/dl associated with symptoms. This definition presents a challenging problem for patients without other medical problems but with symptoms of low testosterone (T) who do not meet the biochemical criteria for therapy.

Objectives

Our objective was to evaluate changes in symptoms and side effects in men with T levels >300ng/dL using human chorionic gonadotropin (hCG) monotherapy for the treatment of hypogonadal symptoms.

Methods

After IRB approval, 31 male patients treated with hCG monotherapy for low T symptoms were retrospectively reviewed. We evaluated changes in hormones, hypogonadal symptoms, and the incidence of thromboembolic events before and after starting hCG.

Results

We found subjective improvement in erectile dysfunction, 86% (19/22), and libido, 80% (20/25), with no patient experiencing a thromboembolic event. In addition, no change was observed in the follicle-stimulating hormone, luteinizing hormone, estradiol, hematocrit, hemoglobin A1c, and prostate-specific antigen.

Conclusion

Weekly treatment with hCG appears safe and can improve hypogonadal symptoms in patients with T >300 ng/dl without changes to hematocrit, prostate-specific antigen, and hemoglobin A1c.

Testosterone kinetics on hypogonadal men under clomiphene

OBJECTIVE

To evaluate total testosterone (TT) kinetics and its predictors 6 months after the discontinuation of clomiphene citrate (CC) in patients with hypogonadism.

MATERIALS AND METHODS

Consecutive patients with normal testicles and male hypogonadism defined by TT < 300 ng/dl in the presence of signs or symptoms according to the previous consensus were prospectively evaluated in a urologic outpatient clinic by TT levels at baseline (T₀), after a daily dose of 50 mg CC for 40 days (T₁), and after the washout period of 6 months of CC discontinuation (T₂).

RESULTS

Among 75 patients, mean age 56.8 years, testosterone at T₁ > 300 ng/dl was achieved by 69 (92%), 450-600 ng/dl by 32 (42.6%), and > 600 ng/dl by 27 (36.0%). 18 subjects (24%) maintained asymptomatic and TT levels over 300 ng/dl at T₂. Age negatively related to testosterone response and T₁ response > 810 ng/dl predicts a median gain of 166.5 ng/dl at 6 months of CC discontinuation.

CONCLUSIONS

CC is a compelling option to treat male hypogonadism, although a chronic treatment is needed in most patients. About one in every four patients respond to a CC short trial to "reboot" the physiology. Further understanding of TT kinetics in these patients in the long term is warranted.

Elevated HCG and retroperitoneal adenopathy after clomiphene therapy for infertility

In the context of an elevated human chorionic gonadotropin (HCG) with enlarged retroperitoneal nodes and absent testicular tumours, clinicians will consider a diagnosis of extragonadal germ cell tumours. We report the case of a man in his thirties who while on treatment for subfertility with clomiphene citrate was noted to have enlarged retroperitoneal nodes and elevated HCG levels of 75 IU/L. Chemotherapy with bleomycin, etoposide and cisplatin originally planned was deferred when two separate retroperitoneal nodal biopsies returned as benign fibroadipose tissue and HCG levels spontaneously down-trended to 4 IU/L within 4 months of clomiphene citrate discontinuation. Follow-up imaging revealed regression of the retroperitoneal nodes.