Introduction: While laser-induced thermal therapy (LITT) has been used for ablative treatment of glioblastoma multiforme (GBM), its histologic effects in a clinical circumstance have not been described. We analyzed tissue from patient that underwent LITT as primary treatment for GBM.
Methods: A 62-year-old male was diagnosed with a left temporal GBM and underwent tumor LITT at an outside institution. Despite corticosteroid therapy, the patient was referred with increasing headache and calculation difficulties associated with progressive peritumoral edema 2 weeks after LITT. En bloc resection of the enhancing lesion and adjacent temporal lobe was performed with steroid independent symptom resolution (follow-up, 2 years).
Results: Histologic analysis revealed 3 distinct histologic zones concentrically radiating from the center of the treatment site. An acellular central region of necrosis (Zone 1) was surrounded by a rim of granulation tissue with macrophages (CD68) (Zone 2; mean thickness, 1.3±0.3 mm [±S.D.]). Viable tumor cells (identified by Ki67, p53 and Olig2 immunohistochemistry) were found (Zone 3) immediately adjacent to granulation tissue. The histologic volume of thermal tissue ablation/granulation was consistent with preoperative (pre-resection) magnetic resonance (MR)-imaging.
Conclusions: These findings reveal that LITT causes a defined pattern of tissue necrosis, concentric destruction of tumor and tissue with viable tumor cells just beyond the zones of central necrosis and granulation. MR-imaging is an accurate surrogate of tissue/tumor ablation in the early period (2 weeks) after treatment.
Patient Care: It will help better define the therapuetic impact of LITT on GBM.
Learning Objectives: 1. To better understand the histologic impact of laser-induced thermal therapy (LITT) in the clinical circumstance.
2. To assess the imaging and histologic correlates of LITT in treatment of glioblastoma multiforme (GBM).
3. To understand the potential advantages and limitations of LITT for GBM.