Answer: B

Histology. The testis showed a teratoma with glands, cartilage, and skeletal muscle differentiation, along with cystic spaces. The cartilage had cytological atypia and the muscle component resembled rhabdomyosarcoma. The cystic spaces were lined cells with abundant glassy dense eosinophilic cytoplasm and contained frequent cytoplasmic vacuoles.

Discussion: With the exception of rare pre-pubertal type teratomas, which are benign both histologically and in terms of behavior, all teratomas in post-pubertal males are malignant. Features important in the recognition of benign pre-pubertal type teratomas are absence of all of the following: cytologic atypia, intratubular germ cell neoplasia, significant tubular atrophy/tubular sclerosis, scarred zones, impaired spermatogenesis, microlithiasis, and evidence of chromosome 12p amplification. Other features include frequent organoid morphology and prominent components of ciliated epithelium and smooth muscle. Once there is a malignant teratoma, one does comment on immaturity or cytological atypia. The only time one would diagnose a sarcoma, carcinoma or other somatic-type malignancy is when the these elements sheet out greater than a 4x low power field. For example, focal rhabdomyosarcomatous elements, as seen in this case, is just part of a malignant teratoma. If the rhabdomyosarcomatous component sheeted out >4x field, then the diagnosis would be a somatic malignancy consisting of rhabdomyosarcoma arising in a teratoma. The other issue in this case is the cystic component. The lining cells are typical of trophoblastic cells with abundant glassy squamoid cytoplasm. Choriocarcinoma, in contrast to the current case, is composed of solid tumor typically with hemorrhagic necrosis and a biphasic component of Syncytiotrophoblastic and cytotrophoblastic cells. The cystic trophoblastic cells were positive for GATA3 and HCG. Cystic trophoblastic tumor may arise from regressing choriocarcinoma where the more aggressive cells are
eliminated either by chemotherapy or spontaneous regression. Also cystic trophoblastic tumor possible may represent an intermediate stage in the “maturation” of choriocarcinoma to teratoma. In the current case and in others published, cysts were partly lined by both trophoblasts and glands, in support of this concept. The importance of cystic trophoblastic tumor, it is totally Prognostically, cystic trophoblastic tumor lesion is similar to teratoma and no further treatment is required after surgery in the absence of other components.