Can stereotactic sample biopsies accurately diagnose mixed germ cell tumors?

Excerpt

We read with great interest the article entitled “Are stereotactic sample biopsies still of value in the modern management of pineal region tumours? Lessons from a single-department, retrospective series” by Lefranc et al. [2]. The authors retrospectively analyzed a series of 88 consecutive patients who underwent stereotactic biopsies for pineal region tumors. They reported that accurate tissue diagnoses were obtained in all but one case, and that the pathological diagnoses included 21 germ cell tumors as well as 32 pineal parenchymal tumors, 15 glial tumors, and 20 other tumors. They concluded that stereotactic biopsies for pineal region tumors could provide accurate pathological diagnoses with safety. We wish to provide further comments, especially regarding the issue of accurately diagnosing germ cell tumors. The authors performed staged biopsies to obtain as much tissue as possible and to optimize the sample collection. Furthermore, when the tumor was too small, they performed rosette biopsies by rotating the side-cut needle. The limited amount of tissue sampling in stereotactic biopsies could result in failure to make an accurate diagnosis, especially when dealing with tumors with mixed components, as mentioned by Lefranc et al. We agree with the authors’ device for avoiding sampling errors. On the other hand, we consider that it is necessary to provide additional information on whether mixed germ cell tumors can be accurately diagnosed in the authors’ series, since the authors did not mention these tumors. Matsutani et al. [3] reported that 32% of intracranial germ cell tumors had coexistence of more than two germ cell tumor components. Depending on the kinds of components present, the treatment strategies can vary, and the outcomes can differ significantly [1, 3]. If mixed germ cell tumors were not diagnosed, we consider that it is too early to reach conclusions on the accuracy of pathological diagnosis with stereotactic biopsies. …