Case 1147: A Man in His 60s with a Testicular Mass

Authors: Matthew Chambers M.D., Ph.D., Sheldon Bastacky, M.D.

Clinical History

A man in his seventh decade of life presents with a unilateral testicular mass, approximately 3-4 cm, which is clinically concerning for malignancy. Serum markers are drawn, and both AFP and beta-hCG are within normal limits. A radical orchiectomy is performed.

Gross Examination

A well-circumscribed, 5 cm lesion with tan solid areas, small cystic spaces, and areas with appearance of hemorrhage (40% of the lesion) are seen. Minimal residual testicular parenchyma is present, and the lesion appears to be grossly confined to the testis.

**Figure 1.** Representative cross-section of the lesion (tan, solid, focally cystic, and hemorrhagic discoloration, surrounded by minimal residual testicular parenchyma, the tunica albuginea and tunica vaginalis.

Histologic and Immunohistochemical Ancillary Studies

Histologic sections of the lesion are then assessed microscopically (see Figure 2).

**Figure 2.** 2A (left). At low power (2x), the tumor is seen to replace much of the testicular parenchyma, with some intratubular tumor present within the residual testicular parenchyma. 2B (right). At higher-power (20x) the testicular tumor is seen to be comprised of a proliferation of dyshesive, malignant cells with high nuclear-to-cytoplasmic ratios, and a small amount of basophilic cytoplasm, with some intermixed intermediate-sized cells, and larger-sized cells. No significant lymphocytic infiltrates are present within the tumor.

Additional ancillary immunohistochemical stains are performed (pan-keratin, c-kit (CD117), OCT3/4, CD30, AFP; see Figure 3). The tumor shows only very rare immunoreactivity for pan-keratin (<1%), patchy and weak immunoreactivity for c-kit (CD117), and is negative for OCT3/4, CD30, AFP and OCT2.

**Figure 3.** Immunohistochemistry. 3A (top-right) Pan-keratin. 3B (top middle) c-kit (CD117). 3C (top left) OCT3/4. 3D (bottom left) CD30. 3E (bottom middle) AFP. 3F (bottom right) OCT2.

Cytogenetic

Given the above immunohistochemical findings, follow-up cytogenetic studies were performed to assess for the presence of chromosome arm 12p via fluorescence in situ hybridization (FISH) studies; however, assessment for the presence of 9p was not available on-site. The results showed that 12p was over-represented in the examined cells, which can be seen in the presence of an isochrome 12p, 12p duplication or chromosome 12 hyperploidy.