Absence Of Testis Research Articles

Origin, proliferation and differentiation of Leydig cells.

Mammalian sex determination involves complex interacting networks of cellular and hormonal signals leading to the development of male or female phenotypes. Three main sequential processes are involved: first, the establishment of chromosomal sex at fecundation (genetic sex); second, the development of the undifferentiated gonad into either testes or ovaries (gonadal sex); and third, differentiation of male or female internal and external genitalia (phenotypic sex). Male phenotype is controlled by two testicular hormones, the anti-Mullerian hormone (AMH) secreted by fetal Sertoli cells which induces regression of the Mullerian ducts, and testosterone produced by Leydig cells which induces differentiation of the Wolffian ducts into male reproductive organs, although conversion of testosterone into dehydrotestosterone is required for masculinization of the external genitalia. In the absence of testes, and therefore in the absence of both AMH and testosterone, the Wolffian ducts regress, creating a permissive environment for the differentiation of the Mullerian ducts and, thereby, female reproductive organs.

Torsion of only spermatic cord in the absence of testis and/or epididymis results in contralateral testicular hypoxia.

Unilateral spermatic cord torsion in the presence or absence of ipsilateral testis causes hypoxia in the contralateral testis. An experimental study was conducted to find the most important structure that causes contralateral testicular hypoxia following ipsilateral twisting. In five groups each consisting of 10 rats sham operations, epididymoorchiectomy, spermatic cord torsion, spermatic cord torsion following subepididymal orchiectomy or spermatic cord torsion following epididymoorchiectomy were performed. Lactic acid, hypoxanthine and thiobarbituric acid reactive products of lipid peroxidation (TBAR) were determined in the contralateral testis. While lactic acid, hypoxanthine and TBAR values did not differ significantly following sham and epididymoorchiectomy procedures, evaluation of other groups revealed significantly increased values compared with sham and epididymoorchiectomy groups. Since torsion of only spermatic cord and testicular vasculature causes contralateral testicular hypoxia, testis and epididymis do not seem to be mandatory for occurrence of contralateral testicular hypoxia. Testicular artery under distress seems to be the most important structure that results in contralateral testicular hypoxia following torsion.

Endocrine Analysis of Childhood Monorchism

Purpose We characterized follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels in boys with surgically documented unilateral absent testes (monorchism) to determine whether measurement of gonadotropin levels could distinguish them from boys with unilateral impalpable cryptorchidism. Materials and Methods Baseline serum gonadotropin levels were prospectively measured in 43 boys 2 months to 14 years old who presented with a unilateral impalpable testis that was confirmed to be absent at surgery. Control serum specimens were obtained from 63 age matched boys undergoing minor surgery with no evidence of hypospadias, or testicular, hormonal or renal diseases. Serum FSH and LH levels were drawn preoperatively and assayed by double antibody radioimmunoassay. A subgroup of 7 boys with monorchism was also evaluated following gonadotropin-releasing hormone (GnRH) stimulation and compared to age matched boys with a unilaterally impalpable testis discovered surgically. Results In the monorchism group mean plus or minus standard deviation basal FSH was 4.08 +/− 0.28 mIU/ml. and LH was 4.13 +/− 0.33 mIU/ml. In the control group mean basal FSH was 4.36 +/− 1.52 mIU/ml. and LH was 4.66 +/− 0.75 mIU/ml. No statistical difference existed between the 2 groups for mean basal gonadotropin level. While monorchid boys were more likely to have elevated FSH levels (p = 0.016), this was not true for LH (p = 0.21). Since gonadotropin levels less than 5 mIU/ml. are accepted normal values, this threshold was applied to FSH and carried a sensitivity of 23.8%, specificity 93.8%, positive predictive value 71.4% and negative predictive value 65.6%. Lower cutoff values marginally improved sensitivity but reduced specificity. Peak stimulated levels of FSH and LH following GnRH stimulation failed to distinguish between boys with 1 or 2 testes. Conclusions Baseline FSH is more likely to be elevated in prepubertal boys with monorchism but it does not appear to be clinically useful when sensitivity and predictive value are poor. Similarly, gonadotropin level following GnRH stimulation is not sufficiently sensitive to advocate the use of hormonal measurements to diagnose prepubertal monorchism.

The Vanishing Testis: Anatomical and Histological Findings

To review anatomical and histological findings in 105 vanishing testes. Records of 2,509 boys with 3,064 cryptorchid testes treated at our hospital between 1969 and 1995 were reviewed. 691 (23%) testes were clinically impalpable. Exploration in 691 impalpable testes revealed absent testis in 144 (21%). In 39 (27%) of the 144 absent testes, there was complete agenesis of testis along with the epididymis and vas deferens whereas 105 (73%) were associated with blind-ending cord structures-the vanishing testis. The site of blind-ending cord structures in 105 vanishing testes was intra-abdominal in 22 (21%), inguinal canal in 62 (59%), superficial inguinal ring in 19 (18%) and scrotum in 2 (2%). Histological information was available in 47 vanishing testes and revealed vas, epididymis, or both in 32 (68%), fibrous/vascular tissue in 11 (23%) and testicular cords in 4 (9%). Dystrophic calcification and/or haemosiderin were present in 7 (15%). Our data show that the incidence of vanishing testis in boys with non-palpable testes is over twice the incidence of testicular agenesis. The most common site of blind-ending cord structures is distal to the internal inguinal ring. The finding of viable testicular tissue at the end of the attenuated cord structures in 4 of our patients, and also reported in other series, suggests that inguinal exploration should be carried out in all patients who on laparoscopy are found to have cord structures entering the internal ring.

Diagnostic and therapeutic laparoscopy of the nonpalpable testis.

We report about laparoscopic examination and treatment of 19 patients with 25 non-palpable testes. Thirteen patients presented with unilateral and six patients with bilateral absent testes, respectively. In all cases of non-palpable testes laparoscopy was able to determine the exact localization and supported the surgical approach. Six testicles were treated by open orchiectomy after diagnostic laparoscopy; three testes were fixed by laparoscopically assisted orchiopexy. Three patients (three testicles) were treated by standard orchiopexy after laparoscopy and in three cases microvascular autotransplantation was performed. Laparoscopically, five aplastic testicles without vas and vessels were diagnosed. Three testes were considered as vanishing and in two patients (two testes) due to previous surgical exploration elsewhere testicular remnants were totally atrophic and were resected with the adjacent vas. All laparoscopic findings except the vanishing testis syndrome were proven either by open surgery or by laparoscopic preparation of the internal inguinal ring.

Benefits and Afterthoughts of Laparoscopy for the Nonpalpable Testis

Purpose Recent reports in the literature indicate that laparoscopy tends to be seen as the most appropriate approach to the nonpalpable testis for diagnosis and therapy. The aim of our study was to evaluate the real benefits of laparoscopy in terms of diagnostic accuracy, safety, costs and validity of the chosen treatment. Materials and Methods We compared anatomical findings and results of the treatment of impalpable testes in 2 pediatric surgical groups, including 47 children treated laparoscopically during a 2 1/2-year period and 296 treated with open surgery (classic orchiopexy) in a 6 1/2-year period. Results There was no significant difference in the diagnosis of abdominal testes (51 versus 50 percent), whereas a difference was noted in inguinal (4 versus 15 percent) and absent testes (45 versus 35 percent). Differences in treatment were more striking. In the laparoscopic group standard orchiopexy was performed in 62.5 percent of cases versus 83 percent in the open group. Conversely the rate of Fowler-Stephens repairs increased from 5.5 percent of open surgery cases to 37.5 percent of laparoscopic cases. There have been no serious complications in the laparoscopic procedures. To date 6 of the 9 patients who underwent a staged Fowler-Stephens procedure have undergone complete repair (open second stage). A review of the literature revealed a similar but lower tendency to over perform the Fowler-Stephens operation in laparoscopic cases (34 percent) versus open surgery (8 percent). Also, in previous series there was a 29 percent orchiectomy rate during laparoscopy compared to only 5 percent in classic open surgery. In Italy under current public health programs overall costs of the laparoscopic approach to the nonpalpable testis become noncompetitive when the procedure is extended from only diagnostic to interventional use due to the need for additional trocars and other special instruments. In contrast, private health insurers provide an additional 30 percent for laparoscopic cases over the cost of open orchiopexy. Conclusions Laparoscopy is definitively accurate in establishing the differential diagnosis of impalpable testis. The number of Fowler-Stephens repairs in the laparoscopic group seems inordinately high, probably due to a lack of definite standards in the proper assessment of the length of the internal spermatic vessel pedicle and the potential scrotal displacement of the testis. This reason may explain the higher number of orchiectomies reported in the literature.

Mullerian inhibiting substance in humans: normal levels from infancy to adulthood.

Mullerian-inhibiting substance (MIS) is a gonadal hormone synthesized by Sertoli cells of the testis and granulosa cells of the ovary. To facilitate the use of MIS for the evaluation of intersex disorders and as a tumor marker in women with MIS-expressing ovarian tumors, we measured MIS in 600 serum samples from males and females. These data show that mean MIS values for males rise rapidly during the first year of life and are highest during late infancy, then gradually decline until puberty. In contrast, MIS values in females are lowest at birth and exhibit a minimal increase throughout the prepubertal years. Whereas MIS is uniformly measurable in all prepubertal boys studied, it is undetectable in most prepubertal female subjects. These data reveal an easily discernible sexually dimorphic pattern of expression and confirm that MIS can be used as a testis-specific marker during infancy and early childhood. MIS values that are above the upper limits for females are discriminatory for the presence of testicular tissue or ovarian tumor, and those below the lower limits for males are consistent with dysgenetic or absent testes or the presence of ovarian tissue. These data will enable normal and abnormal levels of MIS to be differentiated with higher precision and will facilitate the use of MIS in the management of gonadal disorders.

21 MOLECULAR ANALYSIS OF Y CHROMOSOME IN TESTICULAR DIFFERENTATIATION

The aim of our work was to investigate the testicular differentiation mechanism in true hermaphrodites with karyotype XX in order to study the SRY gene and Y heterochromatic region (Yql2-Yqter) by PCR (Polymerase chain Reaction) in these patients and another gonadal patologies. A total of 10 patients were studied: 8 Trues Hermaphrodites (TH): 6 46,XX, 1 45.X/46,XY and 1 45,X/46XY/46,Xinv (Y); a female with Swyer's syndrome 46,XY and 1 Dysgenetic Male pseudohermaphrodite 46,Xr (Y). The SRY gene was present in TH X/XY, X/XY/Xinv (Y) and DMP Xr (Y); it was absent in 6 XXTH and XY female. The Y heterochromatic region was amplified in TH X/XY, X/XY/Xinv (Y) and XY female, and without amplification in THXX and DMP Xr (Y). These results suggest that XXTH could have arisen by an autosomic gene involved in sex reversal or the SRY gene could have been lost in the early stages of embrionary development. The absence of testes and female phenotype in the XY female could be explained by the absence of the SRY gene because of an Y chromosome deletion in the paternal gametogenesis. These data illustaste the usefulness of PCR in the molecular analysis of these patients.

Effect of undernutrition on pulsatile luteinizing hormone (LH) secretion in castrate and intact male rats using an ultrasensitive immunofluorometric LH assay.

The recent development of an ultrasensitive immunofluorometric rat LH assay makes possible evaluation of pulsatile LH secretion in intact male rats under physiological conditions of minimal volume blood sampling without requiring orchidectomy. Specifically, we applied this assay to determine the effect of macronutrient restriction on pulsatile LH secretion in the presence or absence of testes. In testes-intact rats, halving of food intake for 7 days while maintaining micronutrient supply caused a reduction of mean, maximal, and basal LH levels and LH pulse amplitude (all P < 0.05) compared with those in ad libitum fed controls. The loss of body weight was positively correlated with decreases in mean LH level, pulse amplitude, and area under the curve (all P < 0.009). In contrast, the same food restriction in castrated rats caused an increase in pulse length and area under the curve and a decrease in pulse frequency, but did not change mean, maximal, and basal LH levels or LH pulse amplitude compared to castrated ad libitum fed controls (all P < 0.02). The observed positive correlations between body weight and the LH secretion parameters in intact rats were absent or reversed in castrated rats. This study demonstrates qualitatively different effects of macronutrient restriction on pulsatile LH secretion in castrated and intact rats, indicating that it is not necessary valid to extrapolate consequences of undernutrition on LH secretion from castrate to intact male rats. We conclude that undernutrition-induced inhibition of LH secretion involves both an indirect suppression of LH secretion via amplification of endogenous testicular negative feedback as well as more direct suppression of GnRH release.

The Absent Cryptorchid Testis: Surgical Findings and their Implications for Diagnosis and Etiology

On surgical exploration for impalpable testes, there is often found nothing or a nubbin of tissue at the end of the spermatic vessels. This situation is commonly referred to as an absent testis. Controversy exists on how to establish correctly this diagnosis and the degree of investigation required. In addition, there is disagreement concerning whether an absent testis results from early torsion or endocrinopathic event. What is accepted is that the spermatic vessels are singularly important in establishing testis location.In this study, the pathological findings of 117 cases of absent testis diagnosed by surgical exploration at our hospital were reviewed. This diagnosis represented 10% of 1,225 patients explored for cryptorchidism from 1985 to 1991. Average patient age at operation was 26.8 months (range 5 months to 14 years). Of these children 78 (67%) presented with an impalpable left testis.At operation 3 patients (3%) underwent laparoscopy only, while all others had groin exploration with or without transperitoneal exposure to ensure identification of spermatic vessels. In 110 cases surgical specimens or nubbins were excised. Pathological study of these remnants revealed vas deferens in 89 cases (81%), epididymal tissue in 40 (36%) and small amounts of seminiferous tubules with germinal elements in 7 (6.4%). Only 26 specimens (24%) had sufficient vascular tissue present to be suggestive of spermatic vessels. A significant number showed the presence of calcification (35.5%) and hemosiderin (30%) deposits within the remnant.A subset of patients with absent testis possesses testicular tissue of presumed increased malignant potential. Therefore, surgical exploration with spermatic vessel identification and remnant removal is the gold standard for the diagnosis and treatment of the absent testis. The surgeon continues to be responsible for spermatic vessel identification, since the vessels may be recognized at pathological examination in less than 25% of the cases. Also, the common finding of calcification and hemosiderin lends weight to the torsion etiology over endocrinopathy for an absent testis.

Laparoscopic Evaluation of the Nonpalpable Testis: A Prospective Assessment of Accuracy

To assess diagnostic accuracy, laparoscopy and surgical exploration were prospectively performed in 104 children with 126 nonpalpable testes. Laparoscopic localization of the testis was correct in 90% (114 of 126 testes) and was nondiagnostic in 8% largely due to preperitoneal insufflation. No surgical complications occurred. Using the criteria of blind-ending vas deferens and spermatic vessels as diagnostic of an intra-abdominal vanishing testis, the accuracy of diagnosis was 100% but the inability to identify either vas or vessels was associated with intra-abdominal testes in 2 of 3 cases. Identification of canalicular vas deferens and spermatic vessels was associated with testes in 36 of 75 cases (48%). Bilateral nonpalpable testes were significantly less likely to have an absent testis (5%) than a unilateral nonpalpable testis (59%), suggesting the possibility of different pathophysiological mechanisms in those entities. Diagnosis and surgical management of nonpalpable testes were directly impacted by laparoscopy in 42 of 117 testes (36%) by identifying intra-abdominal vanishing testis, the location of an intra-abdominal testes or the need for retroperitoneal exploration when vas deferens and spermatic vessels were not found. Accurate knowledge of testis location in 97% of the testes facilitated development of an appropriate surgical strategy (that is laparoscopic/laparoscopic assisted versus open procedure).

Immunological identification of the protein-producing masculine differentiation of the Wolffian duct in the fetal mouse: western blot analysis and determination of the biological activity.

Recently, we identified a protein in the developing male reproductive tract of the fetal mouse which induced Wolffian duct differentiation in vitro in the absence of testis or testosterone. In this paper, we further evaluated the masculinizing role of this protein using an immunological approach. Thus, we purified a 72K protein from the 18-day-old male fetal reproductive tracts, prepared an antibody against the protein, and determined the role of this protein in producing masculine differentiation of the Wolffian duct using the polyclonal antibody against the protein. We demonstrate that the antibody reacted with the purified 72K protein, producing only one immunoreactive band around the 72K region in Western blot analysis. However, it reacted with 72K and 63K proteins present in the 18-day-old male reproductive tract. Both of these immunoreactive bands disappeared when the antibody was pretreated with the purified antigen. Nonimmune immunoglobulin G (IgG) produced no reactive bands with the extract of the male reproductive tracts. The IgG preparation of the immune serum specifically prevented Wolffian duct differentiation when tested in organ culture containing 13-day-old fetal male or female reproductive tracts in the presence of testis or testosterone (1 micrograms/ml) in a dose-dependent manner. No effect was found on the development of other organs, namely testis, Mullerian duct, and urogenital sinus, that were included in the organ culture. Nonimmune IgG, as expected, produced no effect on Wolffian duct differentiation. Western blot analysis of male and female reproductive tracts indicated a difference in their reactivities with this antibody. In females, the reactivity to the proteins around the 72K and 63K regions was very weak compared to that found with male proteins in those regions. Both of the above bands of the female reproductive tract disappeared when the antibody was pretreated with an excess of female reproductive tract extract, but in males, only the 63K band disappeared, whereas its 72K band remained. In conclusion, it appears that a 72K protein of the male reproductive tract plays a role in the Wolffian duct differentiation of the fetal mouse.

Testicular toxicity of boric acid (BA): Relationship of dose to lesion development and recovery in the F344 rat

High-dose boric acid (BA) produces testicular lesions in adult rats, characterized by inhibited spermiation followed by atrophy. The present study addressed whether inhibited spermiation can be separated from atrophy based on dose, compared testis boron (B) dosimetry to lesion development, determined how inhibited spermiation was reflected by common reproductive endpoints, and examined reversibility of the testicular lesions. Rats were fed 3000, 4500, 6000, or 9000 ppm BA for up to 9 weeks and examined. Recovery was assessed for up to 32 weeks post treatment. Inhibited spermiation could be separated from atrophy based on dose (inhibited spermiation: 3000/4500 ppm; atrophy: 6000/9000 ppm), with each lesion aspect expressed at different threshold testis B concentrations (inhibited spermiation: 5.6 μg B/g and atrophy: 11.9 μg B/g) with no B accumulation during the 9-week exposure. These data suggest that separate mechanisms may be operating for these lesion aspects based on testis B concentration and that B dose rate was important for testicular toxicity. Inhibited spermiation was most reliably reflected by informed testicular histology, with the more severe cases decreasing epididymal sperm count to levels that could affect fertility. After treatment, serum and testis B levels in all dose groups rapidly fell to background levels at the earliest time points evaluated (7 days and 8 weeks posttreatment, respectively). The severely inhibited spermiation at 4500 ppm was resolved by 16 weeks posttreatment, but areas of focal atrophy were detected that did not recover posttreatment. Also, no signs of recovery from atrophy were observed (6000 and 9000 ppm). Atrophic tubules contained a normal complement of spermatogonia (2.6 to 2.9 germ cells/100 Sertoli cells), with occasional dividing and degenerating germ cells. Elevations in serum FSH and LH levels suggested an intact hormonal response to the atrophy. In summary, 1) the different aspects of the BA-induced testicular lesion can be separated using different doses, 2) inhibited spermiation does not necessarily proceed to atrophy, and 3) there is no recovery from the atrophy despite the absence of testis B after treatment. The ability to separate inhibited spermiation from atrophy based on dose and testis B dosimetry will be useful in evaluating possible mechanisms. Furthermore, the presence of dividing spermatogonia during long-term BA-induced atrophy suggests that this model should be useful for identifying critical components involved in the reinitiation of spermatogenesis.

Prenatally diagnosed testicular torsion.

A case is reported of absent testis in a boy of 7 months who was noted to have a cystic intra-abdominal mass at 18-19-week prenatal ultrasound scan. This is the second report of prenatally detected testicular torsion, the previous case being noted much later in pregnancy. On both occasions, the diagnosis was only established after birth.

Testicular prostheses: the patient's perception.

There is a paucity of data to determine if the insertion of a testicular prosthesis is effective in overcoming the psychological effects of an absent testis. A review of 25 patients who had had testicular prostheses showed a high overall level of satisfaction in the 19 patients who were traced. This satisfaction was subject to some qualification.

Laparoscopy for evaluation of cryptorchid testis

Four male patients with a unilateral nonpalpable testis were considered for laparoscopy. Preoperative evaluation by computerized tomography and ultrasonography failed to demonstrate cryptorchid testis. Laparoscopy clearly identified the anatomy in all 4 cases. Two patients had an absent testis, 1 patient underwent orchiectomy for a dysmorphic testis, and 1 patient underwent orchiopexy for a testis located within the inguinal canal. Pediatric laparoscopy is an effective and safe adjunct in the management of cryptorchid testis.

An Absent Testis is Associated with Contralateral Testicular Hypertrophy

Surgical exploration was done in 109 boys ages birth through 9 years with unilateral impalpable testes by physical examination under anesthesia. Of the patients 51 (47%) had an absent testis and 58 had intra-abdominal testes. At open biopsy of the contralateral descended testis the 3 dimensions of the exposed testis were recorded and testicular volume was calculated. The mean volume of the contralateral descended testes of boys with an absent testis was greater than that of boys with intraabdominal testes at all ages. The differences were significant (p = 0.0019 to 0.0117) from birth through year 4 but not from years 5 through 9. However, the standard deviations ranged from 27 to 74% of the means, and there was broad overlap of the volumes of the 2 groups.These findings indicate that, although the volume of the contralateral descended testis of boys with an absent testis is significantly greater than that of boys with intra-abdominal testes, the volume of the contralateral descended testis is not a reliable criterion for differentiating an absent testis from an intra-abdominal testis in a boy with a unilateral impalpable testis. Surgical exploration continues to be the method of choice for making the diagnosis of an absent testis.

Etiopathogenesis, classification, investigations and diagnosis in intersex disorders.

In the last years, advance~ in experimental endocrinology, biochemistry, genetics and molecular biology have all contributed to our understanding of the process of human sex differentiation. In brief, normal sex development consists of three sequential processes. The first is the genetic sex determined at the time of fertilization by the sex chromosome constitution. In the second phase, the genetic information determines that an indifferentiated gonad differentiates either in a testis or an ovary (gonadal sex). Finally, sexphenoO,pe is the result of male differentiation which is an active process resulting of testicular secretions: anti-Miillerian hormone (AMH) produced by the Sertoli cells which inhibits the Miillerian ducts, and testosterone (T) produced by the Leydig cells which is responsible for stabilization of the Wolffian ducts and via its transformation into dihydrotestosterone (DHT) is responsible for virilization of the external genitalia. In the absence of testis, the geni-

Laparoscopy for the impalpable testes: Experience with 53 testes

Impalpable testes constitute approximately 20% of most series of undescended testes. From January 1986 to March 1991, we performed laparoscopies on 53 patients with impalpable testes. Thirty-two of them were found to have normal vasa and vessels entering each internal ring on the side in question. Of these, 14 were found to have “vanishing testes” at exploration, 12 others underwent successful orchiopexy, and the remaining 6 had excisional biopsies of fibrotic testicular remnants. Five patients had no visible vessels and a sixth had a blind-ending vas and vessels adjacent to the internal ring; in these cases no further investigations were deemed necessary. Fifteen patients were found to have abdominal testes and underwent high testicular vessel ligation and division at the time of the laparoscopy; 14 of them have undergone staged orchiopexy 6 months after laparoscopy and one is scheduled for this procedure. A 3-month follow-up of those who had orchiopexy showed excellent results in 10 patients and poor results in 3, all of whom had small testes that were unimproved or worse following vessel ligation. Four boys were spared operations as a result of findings at laparoscopy. Early in the series there was one failed laparoscopy, but it was successfully completed later. The first patient in this series developed peritonitis following the procedure, but it was successfully treated with antibiotics. There were no other complications. Laparoscopy is a safe procedure that allows accurate diagnosis and may prevent additional intervention in the treatment of the absent testes. It facilitates the locating of the impalpable testis and the planning and timing of subsequent orchiopexy. We believe that laparoscopy is the preferred procedure in the management of impalpable testes.

Testicular regression syndrome — a pathological study of 77 cases

Testicular regression syndrome is characterized by a rudimentary epididymis and spermatic cord with absence of testicular tissue. Although it has been well-described in the surgical literature, few pathological studies have been performed. We report 77 cases of the syndrome, deriving from a 26-year retrospective review. Typical gross descriptions described several cm of spermatic cord with a small mass of firm, fibrotic tissue at one end; elements of the vas deferens, spermatic artery and venous plexuses were usually present. Histologically, the distal expansion of most of the specimens was composed of dense fibrovascular tissue with no evidence of seminiferous tubules or normal testicular elements. Instead, scattered foci of calcification and brown pigment were present. The finding of dystrophic calcification and haemosiderin deposition, with no evidence of viable testicular tissue, in the presence of relatively normal spermatic cord elements, supports the concept of generally unilateral and occasionally bilateral anorchia secondary to remote infarction. The young age of the patients, coupled with the history of an absent testis from birth, is supportive of in utero damage. These histopathological findings provide support for the concept of in utero torsion of the testis as the basis for the testicular regression syndrome.