Case No.: G-002

Diagnosis: Mixed germ cell tumor, predominantly seminoma with focal embryonal cell carcinoma and yolk sac tumor

Organ: Testis

Last Updated: 12/21/2011

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Hematoxylin & eosin

Area 1: Seminiferous tubules are illustrated here.

Hematoxylin & eosin

Area 2: This is the seminomatous component. There is very little lymphocytes accompanying this tumor. See Bonus Images below.

Hematoxylin & eosin

Area 3: This neoplastic foci is composed of tumor cells significantly larger than the seminomatous component. While some of the areas are composed of solid sheets of large pleomorphic cells, there are other areas that arrange into structures with a lumen. These areas represent a mixture of embryonal cell carcinoma and yolk sac tumor. Scant syncytiotrophoblasts are also noted (arrow).

History: This specimen was obtained from a 28 year-old man. What is this organ? What is your diagnosis?

 

Histologic Highlights of this Case:

  • The are seminiferous tubules present which indicate that this is a testis (Area 1).

  • The bulk of this tumor (95%) is composed of a densely packed rather monotonous neoplastic proliferation characterized by polygonal cells with high nuclear to cytoplasmic ratio and large, centrally located nuclei with prominent nucleoli (Area 2). These features are diagnostic of a seminoma. However, there is a focus that has different morphology (Area 3). This is an area with mixed features of embryonal cell carcinoma and yolk sac tumor.

  • Therefore, this is a mixed germ cell tumor with predominantly seminoma component with foci of embryonal cell carcinoma and yolk sac tumor. There are also rare syncytiotrophoblasts.

Comment:

  • This case illustrated four interesting points. First, the amount of lymphocytes in seminoma can be very variable. Lymphocytes can dominant the histopathologic picture to the extent that seminomatous tumor cells are not readily seen to near total absent as illustrated in this case. It should be noted that seminoma can also undergo extensive granulomatous changes to the extent that the tumor cells are not readily seen. Both situation may lead to a wrong diagnosis.

  • In mixed germ cell tumor, embryonal cell carcinoma and yolk-sac tumor component often mix together.

  • In the case being shown here, the focus of embryonal cell carcinoma and yolk sac tumor is very small and this is the only focus being found in the entire specimen. This illustrated the importance of thorough examination of all germ cell tumors. Embryonal cell carcinoma and yolk sac tumors are positive for cytokeratin and embyronal cell carcinoma is positive for CD30. These tools are helpful in demonstrating these component when their amount is scant and also for confirmation of diagnosis.

  • The morphology of seminoma is quite affected by fixation. See Bonus Images below.

Bonus Images:

Hematoxylin & eosin

Germinoma from pineal gland: These images are obtained from a germinoma of the pineal glands. The fixation is optimal and the morphology of the seminomatous neoplastic cells can be clearly seen. They are usually large round to polygonal, with a large nuclei and prominent nucleoli. Also, a substantial amount of lymphocytes are also present in contrast to our current.

Original slide is contributed by Dr. Kar-Ming Fung, University of Oklahoma Health Science Center, Oklahoma, U.S.A.

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