Histologically, spermatocytic tumors consist of three cell populations:
small cells with a large nuclear-to-cytoplasmic ratio (6-8 µm),
medium-sized cells with prominent nucleoli (15-18 µm) and,
large cells (50-100 µm).

The cells are generally packed into nodules, and have a loose, sheet-like arrangement that is commonly interrupted by interstitial oedema.
 Unlike classical seminoma, fibrous septation and lymphocytic infiltrates are not seen.
 Cells undergoing mitosis are common, as are cells undergoing apoptosis.

Intratubular growth of spermatocytic tumor can be seen, however there is no intratubular germ cell neoplasia of unspecified type (IGCNU).
 The intratubular growth probably accounts for the appearance of separate tumour nodules within the testis.

Immunostaining for most of the usual testicular germ cell tumour markers is negative (i.e. placental alkaline phosphatase (PLAP), vimentin, actin, desmin, alpha fetoprotein (AFP), OCT4, human chorionic gonadotropin (hCG), and carcinoembryonic antigen (CEA)).

Rarely, spermatocytic tumors may show sarcomatoid differentiation, most commonly as undifferentiated spindled cells intermingled within the typical-appearing spermatocytic tumor cells.
 Rhabdomyosarcomatous differention has also been described.
Histologically, spermatocytic tumors consist of three cell populations:
small cells with a large nuclear-to-cytoplasmic ratio (6-8 µm),
medium-sized cells with prominent nucleoli (15-18 µm) and,
large cells (50-100 µm).
The cells are generally packed into nodules, and have a loose, sheet-like arrangement that is commonly interrupted by interstitial oedema.  Unlike classical seminoma, fibrous septation and lymphocytic infiltrates are not seen.  Cells undergoing mitosis are common, as are cells undergoing apoptosis.
Intratubular growth of spermatocytic tumor can be seen, however there is no intratubular germ cell neoplasia of unspecified type (IGCNU).  The intratubular growth probably accounts for the appearance of separate tumour nodules within the testis.
Immunostaining for most of the usual testicular germ cell tumour markers is negative (i.e. placental alkaline phosphatase (PLAP), vimentin, actin, desmin, alpha fetoprotein (AFP), OCT4, human chorionic gonadotropin (hCG), and carcinoembryonic antigen (CEA)).
Rarely, spermatocytic tumors may show sarcomatoid differentiation, most commonly as undifferentiated spindled cells intermingled within the typical-appearing spermatocytic tumor cells.  Rhabdomyosarcomatous differention has also been described.
Spermatocytic tumor