Parvovirus B19 Persistence in Abnormal Thyroid Tissue of a Mature Cystic Ovarian Teratoma: A Case Report

Ovarian teratomas represent the most common neoplasm derived from germ cells and can contain mature ectodermal, mesodermal, and endodermal tissues. In rare cases, these teratomas can be composed predominantly or solely of thyroid tissue. These thyroid cells often function similarly to normal thyroid tissues. This laboratory and others have previously shown that parvovirus B19 (B19V) persists in primary and metastatic thyroid tissues. No reports exist on possible B19V persistence in thyroid tissues that may arise de novo outside the thyroid gland proper. In this case report, the detection of B19V (genotype 1) in the thyroid epithelial cells of a mature teratoma is reported. Nested PCR and immunohistochemistry were used to detect viral nucleic acids and proteins, respectively. Viral genomes were amplified in lesion DNA, confirming persistence of B19V. Positive immunohistochemical staining was seen for B19V capsid proteins in the thyroid epithelial cells within the mature teratoma, but not in surrounding ovarian tissue or in the non-thyroidal elements of the mature teratoma. These results demonstrate for the first time that thyroid epithelial cells, derived from non-thyroid tissue, are capable of supporting B19V infection and persistence.