Testing Testes: Problems and Recent Advances in the Diagnosis of Testicular Tumours and Implications for Treatment

Pagetoid involvement of the rete testis with seminoma. Malignant cells with large irregular nuclei lining the circumference of a rete testis tubule. A mitotic figure is arrowed.

Spermatocytic seminoma showing large, medium and small cells with darkly staining nuclei. The low power appearance may be confused with a ‘classical’ seminoma.

Metastatic yolk sac tumour within a retroperitoneal lymph node dissection mass. The tumour shows a glandular architecture, which could be confused with other morphologically similar malignancies, e.g. colorectal carcinoma. A brush border may even be present in places.

Cystic trophoblastic tumour. Although there are atypical features, such as nuclear hyperchromatism and visible nucleoli, the presence of this lesion does not necessarily necessitate further chemo- or radiotherapy.

Malignant Leydig cell tumour showing a sheet-like growth pattern, polygonal cells, pink cytoplasm and variably sized nuclei. Mitoses are infrequent (arrowed).

Somatic transformation of teratoma into adenocarcinoma. This is a metastatic deposit within a lymph node and could be confused with a metastasis from somatic tissue.

Large cell calcifying Sertoli cell tumour. Note the dominant calcific body (arrowed).

Immunostaining for OCT3/4 in carcinoma in situ. There is clear nuclear positivity of neoplastic cells only.