Characterizing Pain in Peripheral Nerve Tumors: Interim Results from a Prospective Bicenter Cohort.

Background/Objectives: This prospective study used a standardized preoperative assessment to characterize the full spectrum of pain in patients with peripheral nerve tumors, addressing the lack of structured pain phenotyping in this population. Methods: Between June 2024 and October 2025, preoperative pain symptoms were assessed in 91 patients, representing 16% of the Peripheral Nerve Tumor Registry (PNTR) cohort, using the PainDETECT questionnaire (0-38) at two centers: University Hospital Ulm, Günzburg (n = 72), and University Hospital Essen (n = 19). Results: Ninety-one patients (61.5% male; mean age, 49 years) were included. Most tumors were located in the lower extremity (54.9%). PainDETECT scores were ≤12 in 51.6%, 13-18 in 24.1%, and ≥19 in 21.9% of patients. Malignant tumors (6.5%) had the highest mean score (17), but benign tumors also showed a relevant pain burden (mean 11.9). Hybrid peripheral nerve sheath tumors and neurofibromas had numerically higher mean scores than schwannomas, although the difference was not statistically significant. Pain severity was not associated with tumor size, depth, or affected nerve. The most common sensory features were electric-shock-like and pressure-related pain, as reflected by a positive Tinel sign in 86.8% of patients. The most frequent pain pattern was intermittent attacks with pain-free intervals (46%). Conclusions: These interim results indicate that pain is common even in benign peripheral nerve tumors, challenging the assumption that these lesions are often asymptomatic. Malignant tumors showed the highest pain scores. The heterogeneous pain phenotypes highlight the need for individualized assessment and management. Expansion to a multicenter evaluation within the framework of the PNTR is planned.