Figure 2.

Testicular touch preparation from a normal testis biopsy showing germ cells in varying stages of spermatogenesis. Complete maturation of germ cells is evident, beginning with spermatogonia (intermediate-sized cells with a high N : C ratio containing single, oval-to-round, darkly stained nuclei with even chromatin), followed by spermatocytes (slightly larger cells with nuclei containing more coarse or thread-like chromatin), and finally spermatids (small-sized cells with minimal cytoplasm, darkly stained small, oval nuclei) as well as spermatozoa (usually with an indistinct tail on Pap stain). Note that as the chromosomal structures become more prominent in the primary spermatocytes their nuclear outline becomes more irregular. As shown in this image, spermatids tend to be found in groups. The Sertoli cell seen in this TP has cytoplasm with poorly delineated cell borders and a vesicular, oval nucleus, with smooth contours and a distinct, large nucleolus. (×600 magnification; Pap stain)