Placental alkaline phosphatase in cerebrospinal fluid as a biomarker for optimizing surgical treatment strategies for pineal region germ cell tumors

Pineal region germ cell tumors are a heterogenous group of tumors; of these, pure germinoma shows high sensitivity to adjuvant therapy, and the timing and sequence of surgical intervention and adjuvant/neoadjuvant therapy are important for devising a treatment strategy for intracranial germ cell tumors (IGCT). Biopsy is diagnostically useful, but is often insufficient because only a limited amount of specimen can be obtained. In the present study, we aimed to determine the value of cerebrospinal fluid placental alkaline phosphatase (PLAP) levels, reflecting the presence of germinoma, as a reliable indicator to determine treatment strategies for pineal germ cell tumors. To assess the relationship between elevated PLAP levels and the presence of germinoma, we retrospectively reviewed histopathological findings of 25 surgical cases of IGCT in the pineal region. The PLAP value reflects the existence of a germinoma component within a total tumor volume; consequently, tumor volume could be reduced in cases with elevated PLAP, while tumors negative for PLAP did not decrease in size. Therefore, PLAP levels may help neurosurgeons optimize surgical intervention timing for teratomas in the pineal region.