Is histological diagnosis necessary to start treatment for germ cell tumours in the pineal region?

The significance of histological diagnosis was retrospectively investigated in the treatment of 79 consecutive patients with pineal region tumours. Histological diagnoses were consistent with clinical diagnoses in 38 out of 39 patients with germ cell tumours and in all eight patients with non-germ cell tumours. The single exception was pineoblastoma. Forty-one patients were treated under a clinical diagnosis of pineal germ cell tumour using neoadjuvant chemotherapy and radiation therapy without histological verification. Of the 41 patients, 32 achieved an excellent response, whereas nine required the delayed resection of a residual tumour. Of these nine tumours, seven were mature or immature teratomas or scars. These patients had elevated levels of tumour markers. Most cases of pineal germ cell tumour could be identified on the basis of clinical findings only, and could be treated appropriately using neoadjuvant chemotherapy and radiation therapy without histological diagnosis. However, second-look surgery should be considered in cases with residual teratomatous components or unusual responses.