Concerning the Seminal Study of Anterior Mediastinal Teratomas by H. G. Schlumberger: An Update and Modern Contextualization

Pure teratomas of the AM in children are benign type I GCTs that may dedifferentiate to yolk sac tumor, possibly from embryonic-type neuroectoderm. Mature teratomas in postpubertal patients, comprising ∼95% of GCTs in females but only ∼30% in males, are hybrid type I and type IV teratomas. Such cases show organoid structures and benign cytology. They derive from nontransformed germ cells and lack metastatic potential. Immaturity does not alter the outcome in children. In contrast, many teratomas in postpubertal males are type II GCTs, derived from malignantly transformed germ cells that initially form a primitive GCT, with subsequent teratomatous differentiation. These teratomas, consequently, are components of mixed GCTs and show cytogenetic abnormalities, including overrepresentation of chromosome arm 12p. They are cytologically atypical and less commonly organoid; their most frequent associated GCT is yolk sac tumor, which may be the source of somatic-type malignancies of type II AM GCTs, especially the virtually uniquely associated hematologic malignancies and vascular neoplasms of GCT origin. All AM GCTs are believed to derive from mismigrated germ cells.