The spectrum of splenogonadal fusion. Case report and review of 84 reported cases.

Splenogonadal fusion is a rare congenital malformation in which there is an abnormal fusion between the spleen and the gonad or derivatives of the mesonephros. It can occur in both sexes but has been reported far more frequently in males. There are two types of this malformation: the continuous and the discontinuous type, depending on the presence or absence of a structural connection between the regular spleen and the ectopic splenic tissue that is fused to the gonad. In one-third of all reported cases splenogonadal fusion is associated with other congenital defects. This association is predominantly found within the continuous type. Peromelia is present in a high percentage of cases, varying from total absence of all limbs to absence of parts of the lower limbs. On the basis of a case report and a review of 84 published cases, the causal, pathogenetic and nosologic aspects of this malformation are discussed. We hypothesise that splenogonadal fusion with peromelia and splenogonadal fusion without peromelia represent two ends of one spectrum determined by the developmental stage during which the causal factor acts.