Histopathological Diagnosis of Primary Central Nervous System Lymphoma after Therapy with Corticosteroids or Anticoagulants

Simple Summary In most cases, it is impossible to differentiate primary central nervous system lymphoma (PCNSL) from other brain tumors or neuroinflammatory diseases without histological confirmation. In most differential diagnoses of PCNSL, preoperative treatment with glucocorticoids is administered. This treatment reduces the symptoms of PCNSL but can also disguise the histological diagnosis, which can lead to an incorrect or delayed diagnosis of PCNSL and postponed therapy. To obtain a broader database for evidence-based decisions in the management of patients with PCNSL, we retrospectively evaluated all patients biopsied and diagnosed with PCNSL at our institution over the last 16 years. Particular focus was placed on the influence of preoperative glucocorticoid therapy and the effect of anticoagulation and dual antiplatelet therapy on the validity of histological diagnosis.Abstract In patients with primary central nervous system lymphoma (PCNSL), the choice of surgical strategy for histopathologic assessments is still controversial, particularly in terms of preoperative corticosteroid (CS) therapy. To provide further evidence for clinical decision-making, we retrospectively analyzed data from 148 consecutive patients who underwent surgery at our institution. Although patients treated with corticosteroids preoperatively were significantly more likely to require a second or third biopsy (p = 0.049), it was only necessary in less than 10% of the cases with preoperative (but discontinued) corticosteroid treatment. Surprisingly, diagnostic accuracy was significantly lower when patients were treated with anticoagulation or dual antiplatelet therapy (p = 0.015). Preoperative CSF sampling did not provide additional information but was associated with delayed surgery (p = 0.02). In conclusion, preoperative CS therapy can challenge the histological diagnosis of PCNSL. At the same time, our data suggest that preoperative CS treatment only presents a relative contraindication for early surgical intervention. If a definitive diagnosis cannot be made after the first surgical intervention, the timing of a repeat biopsy after the discontinuation of CS remains a case-by-case decision. The effect of anticoagulation and dual antiplatelet therapy on diagnostic accuracy might have been underestimated and should be examined closely in future investigations.