The C134W (402 C > G) FOXL2 mutation is absent in ovarian gynandroblastoma: insights into the genesis of an unusual tumour

Aims: Ovarian gynandroblastomas are rare tumours that, by definition, comprise a combinationof components resembling both female, typically granulosa cell tumour (GCT), and male, typically Sertoli or Sertoli/Leydig cell tumour (ST/SLT), sex cord/stromal differentiation. The histogenesis of these tumours is unknown and, in view of the very strong association between the C134W (402 C> G) FOXL2 mutation and adult- type GCT, we analysed a series of gynandroblastomas for this mutation.

Methods and results: Both components of each lesion were isolated by laser capture microdissection and the C134W (402 C> G) FOXL2 mutation was analysed by polymerase chain reaction sequencing. No mutation was identified in either the GCT or ST / SLT component of six cases, three of which contained adult- type GCT.

Conclusions: This suggests that, despite their similar morphological appearances, the GCT- like component of gynandroblastoma has a different molecular basis from conventional adult- type GCT. This finding underscores a more general principle that morphological similarity does not necessarily indicate molecular identity.