Answer: E. Vanishing testes syndrome

Histology:
The resection consists primarily of fibrovascular and adipose tissue with a focal area reminiscent of epididymis, but there are no seminiferous tubules or leydig cells. There are no germ cells. There is a region of hemosiderin laden macrophages, fibrosis, and dystrophic calcifications. These features in a cryptorchid testis are consistent with “vanishing testes syndrome” (also called “testicular regression syndrome”).

Discussion:
The three key features of vanishing testes syndrome (also termed “testicular regression syndrome”) are the presence of fibrosis, hemosiderin-laden macrophages and dystrophic calcifications. These changes occur in cryptorchid, undescended testes that undergo atrophy usually due to torsion (i.e., cut-off of the blood supply leading to infarction and atrophy). Undescended testes are resected to decrease the risk of developing subsequent germ cell neoplasia. Theoretically, the risk of developing germ cell neoplasia would be low in truly “vanished” testes, as there are no residual seminiferous tubules; in contrast, the risk of germ cell neoplasia is much higher in undescended, intra-abdominal testes.

In general, the differential diagnosis to keep in mind while evaluating a gonadal specimen from a child include: the presence of mixed germ cell types (ovotestis), the presence or absence of any seminiferous tubules, the presence of germ cell neoplasia, and the possibility of a paratesticular rhabdomyosarcoma.

References:
1. Pirgon Ö, Dündar BN. Vanishing testes: a literature review. J Clin Res Pediatr Endocrinol. 2012 Sep;4(3):116-20.