The validity of testicular aspirate cytology and DNA image-analysis of the aspirate in the assessment of infertile men

To assess the possibility of using cytological examination and DNA image-analysis of testicular fine-needle aspirates instead of open surgical biopsy in the investigation of infertile men, as testicular biopsy has long been used for investigating infertility but the interpretation of histological slides is usually subjective.

Patients and methods:
Thirty-three men (aged 22–36 years) were evaluated for infertility and underwent both open biopsy and fine-needle aspiration of their testes. Subsequently, the needle aspirates were assessed histopathologically and cytologically, and by DNA image cytometry. The percentages of haploid, diploid and tetraploid cells were determined for each patient.

Results:
The cases were divided into four categories: (1) Complete spermatogenesis, with a DNA pattern of 1n > 2n > 4n; (2) Maturation arrest, with a DNA pattern of 2n > 4n with no haploid cells; (3) Sertoli cell-only syndrome, with a DNA pattern of only 2n, with no haploid or tetraploid cells; (4) Hypospermatogenesis, with a variable DNA pattern, i.e. mild with 1n > 2n, moderate with 2n > 1n > 4n, and marked where the DNA pattern was 2n > 4n > 1n. From the cytological and DNA image-analysis of the aspirate a diagnosis was possible that had a strong correlation with the histological diagnosis of the same case. From image analysis we could exclude interstitial cells, Sertoli cells and sperms on the static image, and differentiate between spermatozoa and spermatids based on morphological characteristics in the cytological smear. This technique can therefore be used to quantitatively determine the percentages of various cell types within the seminiferous tubules. By coupling image ploidy analysis and cytological examination of a cytological smear, spermatogenesis can be assessed accurately.

Conclusion:
Image cytometry could be used to exclude interstitial cells, Sertoli cells and sperms on the static image and so produce an accurate assessment of spermatogenesis. A combination of ploidy and cell morphology characteristics in cytological smears provides an accurate, reproducible and easily used alternative to open testicular biopsy.