Abstract
Aim Congenital monorchism is considered a condition in which an initially normal testis
has existed but subsequently atrophied and disappeared due to a third trimester catastrophe
(presumably torsion). Since inhibin B concentrations appear related to Sertoli and
germ cells number, we evaluated pre- and postoperative inhibin B of boys with congenital
monorchism to determine whether the well-known hypertrophy of the contralateral testis
was reflected in inhibin B concentrations.
Materials and Methods Twenty-seven boys consecutively diagnosed with congenital monorchism (median age
12 months) underwent follow-up with reproductive hormones 1 year postoperatively (median
age 25 months). The results were compared with inhibin B of 225 boys with congenital
nonsyndromic unilateral cryptorchidism, by converting values to multiple of the median
(MoM) for age in normal boys.
Results Ten boys (37%) had blind-ending vessels and ductus deferens (vanished testis) and
the remaining (63%) had testicular remnants. At the time of diagnostic procedure,
monorchid boys did not have significantly lower inhibin B (median 114, range 20–208)
than unilateral cryptorchid boys (136, 47–393) (p = 0.27). During follow-up, MoM values of inhibin B increased in monorchid boys (median
0.59 to 0.98) and in unilateral cryptorchid boys (0.69 to 0.89) (both p < 0.0001). Compared with the concentration at surgery, an additional 44% monorchid
boys had inhibin B MoM values higher than 1.0, whereas only additional 23% of unilateral
cryptorchid boys exhibited such values (p = 0.04).
Conclusion Generally, inhibin B MoM values were normalized during follow-up in boys with congenital
monorchism, reflecting compensatory hypertrophy within the first 2.5 years of life.
The compensatory capacity to increase was better in monorchism than in unilateral
cryptorchidism.
Keywords
monorchism - vanished testis - testicular regression syndrome - inhibin B - compensatory
testicular hypertrophy
