The Natural Evolution of Spontaneously Regressing and Disappearing Bone Tumors and Tumor-Like Lesions

Purpose or Learning Objective: To review the literature on bone tumors and tumor-like lesions that have the potential to undergo spontaneous regression. Entity-specific information is provided about the potential, likelihood, and frequency of spontaneous remission under various conditions, offering guidance to clinicians on the potential for a “watchful waiting” or “do-not-touch” approach. The study does not seek to establish the biological mechanisms underlying tumor regression but rather to compile existing case-based evidence supporting the relatively rare phenomenon.

Methods or Background: A comprehensive literature review was conducted using PubMed and case presentations published on Radiopaedia and in major radiologic conference archives (European Congress of Radiology, European Society of Musculoskeletal Radiology, International Society of Radiology, and Radiological Society of North America). Search terms were combinations of “spontaneous,” “regression,” “remission,” “natural course,” “disappearing,” and “healing” with bone tumor–related keywords such as “bone lesion,” “bone neoplasm,” and “tumor-like lesion.” Articles reviewed included case collections, individual case reports, and review articles in English. Abstracts were screened for evidence of complete regression, with full-text articles assessed when abstracts lacked definitive terminology. Inclusion criteria required evidence of complete tumor resolution on cross-sectional imaging (computed tomography and/or magnetic resonance imaging). Regression was defined as the disappearance of more than two thirds of the original tumor abnormality. Entities with at least three documented cases meeting these criteria were included in the review.

Results or Findings: A total of 25 publications were analyzed. The review identified multiple benign bone tumors and tumor-like lesions that demonstrated spontaneous regression, including but not limited to osteochondromas, enchondromas, eosinophilic granulomas, simple bone cysts, (osteo-) fibrous dysplasia, osteoid osteomas, aneurysmal bone cysts, and giant cell tumors. Factors associated with regression included skeletal maturity, anatomical locations, mechanical stress (e.g., fractures), and minor (nontherapeutic) surgical interventions such as needle biopsy. Cross-sectional imaging confirmed regression in all included cases, with radiographs alone deemed insufficient for definitive assessment.

Conclusion: Spontaneous regression of certain benign bone tumors and tumor-like lesions is well documented but often underappreciated. Awareness of this phenomenon can help clinicians and radiologists avoid unnecessary interventions and opt for surveillance when appropriate. Further research is needed to elucidate the biological and biomechanical factors initiating and influencing tumor regression.

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Artikel online veröffentlicht:
02. Juni 2025