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mixed atrophy of the testis

Monday 23 January 2012

Mixed atrophy of the testis (MAT) is a frequent finding in biopsies of formerly cryptorchid and/or infertile patients.

Mixed atrophy of the testis (MAT) is defined as the synchronous occurrence of both seminiferous tubules containing germ cells and Sertoli cell only-tubules in variable proportions.

In tubules containing germ cells, different types of abnormalities in spermatogenesis may be seen.

The presence of adult spermatids in the biopsy, even in small numbers, correlates with successful spermatozoa retrieval for "in vitro" fertilization techniques.

Currently, it is unknown whether precursor lesions of MAT can be identified in cryptorchid patients during childhood.

In prepubertal biopsies, abnormalities of the testicular parenchyma were classified into:
- type I (slight alterations),
- type II (marked testicular germinal hypoplasia),
- type III (severe testicular germinal hypoplasia).

In postpubertal biopsies, the percentage of tubules containing germ cells and Sertoli cell only-tubules can be estimated, as well as the presence of complete spermatogenesis.

Abnormalities in spermatogenesis are classified into lesions of the adluminal or basal compartments of seminiferous tubules.

Comparison between prepubertal and postpubertal biopsies revealed that most specimens developing from type III lesions presented with incomplete spermatogenesis (P < 0.0001) and more severe lesions of the germinal epithelium (P=0.049).

Type III lesions correlated with MAT characteristics that confer a worse prognosis for in vitro fertilization. Thus, MAT characteristics may be predicted in prepubertal cryptorchid patients, allowing a fertility prognosis.

See also

- testicular dysgenesis syndrome.