Congenital thyroid teratoma: a case with persistent neuroglial involvement of cervical lymph nodes

A case of congenital thyroid teratoma with nodal spread is reported. Primary surgery was performed on a female infant on the 6th day of life. The thyroid mass was removed in toto, and an adjacent 1.2 cm lymph node was also removed. Histology showed solid and cystic teratoma with a variety of elements including prominent neurological tissue that was neuroblastoma-like in places. Residual compressed non-neoplastic thyroid tissue was identified in the subcapsular plane. The lymph node was largely replaced by neuroglial tissue that was cellular in some areas and showed intrasinusoidal growth and some mitotic activity. Recurrent cervical lymphadenopathy gradually developed, commencing a few months after surgery. Excision of cervical nodes was undertaken at 9 months of age. About 13 nodes up to 2 cm in diameter were excised. Most of the specimens consisted of reactive lymph nodes, but in three of the smaller nodes, there were subcapsular and sinusoidal masses of focally cellular neuroglial tissue, again with occasional mitoses. This tissue stained strongly for glial fibrillary acidic protein, in addition to expressing neural markers. The lymph node "deposits" were interpreted as "displaced" lesional tissue rather than metastases in the usual, aggressive sense. The girl remains well at 5 years of age.