Molecular Evidence Supporting the Neoplastic Nature of Some Epidermoid Cysts of the Testis

Abstract

Context.—Loss of heterozygosity (LOH) on chromosomes 9p and 12q is common in germ cell tumors of the testis. Loss of heterozygosity of 17p13 has also been demonstrated in germ cell tumors. The incidence of LOH in epidermoid cysts, a possible special form of teratoma, has not been previously determined. Objective.—To determine the frequency of LOH in epidermoid cysts. Design.—Eight testicular epidermoid cysts and surrounding parenchyma were microdissected from formalin-fixed, paraffin-embedded tissue, and the genomic DNA was extracted using proteinase K. Polymerase chain reaction analysis targeted regions on chromosome 9p21 (D9S177 and D9S161 loci), chromosome 12q22 (D12S1051 locus), and chromosome 17p13 (TP53 locus). Gel electrophoresis followed by autoradiography was used to detect LOH. Results.—All 8 of the epidermoid cysts were informative at a minimum of 1 of 4 loci. Three demonstrated LOH. In 2 tumors, LOH occurred on chromosome 9, and the third tumor demonstrated LOH on chromosome 12. Loss of heterozygosity on chromosome 17p13 was not present in any of the tumors. Conclusions.—Epidermoid cysts harbor allelic loss at some of the same loci identified in malignant testicular germ cell tumors. Our findings support that some examples of epidermoid cysts are neoplastic, although their low frequency of LOH also supports that they are genetically different from malignant germ cell tumors.

Unusual presentation of epidermoid cyst from testis in an aging male

“…All non-tumoral lesions could be detected in the frozen-sections during the testicular sparing surgery, whereas the skipping ratio is 3.5% for tumoral lesions [11]. In the literature, a testicular epidermoid cyst concurrent with intratubular germ cell neoplasia was reported as well as a pure seminoma which developed after 5 years from the testicular sparing surgery due to a testicular epidermoid cyst which was reported in the frozen-sections [12,13]. Aggressive treatments might be considered given the malignancy of 95% of the testicular tumors after puberty and inability of excluding the malignancies with clinical findings and imaging studies.…”