# Spontaneous Regression of Pediatric Osteochondroma: Clinical Case and Comprehensive Literature Review

## TL;DR

A child's benign bone tumor spontaneously regressed over six years, a rare occurrence that may avoid surgery in similar cases.

## Contribution

This paper presents a rare case of spontaneous regression in a pediatric osteochondroma and reviews existing literature to identify patterns and mechanisms.

## Key findings

- Spontaneous regression occurred in a six-year-old with a solitary osteochondroma of the distal femur.
- Regression was observed predominantly in skeletally immature males with solitary lesions.
- Physeal remodeling is proposed as a likely mechanism for regression in such cases.

## Abstract

Osteochondromas are the most common benign bone tumors in children, typically arising in the metaphyseal regions of long bones. While most lesions remain asymptomatic and stable, their natural history is not fully understood, and spontaneous regression is exceptionally rare. We present the case of a six-year-old boy with a solitary pedunculated osteochondroma of the distal femur who was managed conservatively. Initial radiographs demonstrated a stalk-like exostosis arising from the medial aspect of the distal femur without features of hereditary multiple exostoses. The patient remained clinically stable, and serial imaging revealed progressive reduction in tumor size, with marked regression noted at three years and near-complete resolution by six years. Throughout follow-up, the patient reported no pain or functional limitation.

A review of 38 published cases, including the present case, showed that regression occurs predominantly in skeletally immature patients, with a male predominance (76.3%), solitary lesions in most cases (97.4%), and the distal femur and proximal humerus as the most frequent sites. The mean regression period was 4.2 years. Proposed mechanisms include physeal remodeling, fracture-induced remodeling, and vascular compromise, with physeal remodeling most consistent with the present case. Recognition of this rare phenomenon is important because observation with regular follow-up may be a safe alternative to surgery in asymptomatic children, thereby avoiding operative risks.