# A Systematic Review of Cutaneous Involvement in Metastatic Bone Sarcomas: Insights from 102 Reported Cases

## TL;DR

This study reviews 102 cases to better understand rare skin metastases from bone sarcomas, revealing distinct patterns and outcomes by sarcoma type.

## Contribution

The study provides the first systematic analysis of cutaneous metastases in different bone sarcoma types, highlighting their varied clinical behaviors.

## Key findings

- Osteosarcoma and Ewing sarcoma often show skin involvement with poor prognosis due to widespread disease.
- Chordoma frequently presents with slower-progressing skin metastases and occasional long-term survival.
- Cutaneous metastases in bone sarcomas vary significantly by histology, affecting diagnosis and treatment approaches.

## Abstract

Cutaneous metastases from primary bone sarcomas are very rare and not well understood, often leading to diagnostic delays or misinterpretation. This review analyzes over 100 reported cases to describe their clinical patterns, including location, timing, appearance, and outcomes across different sarcoma types. We found distinct behaviors: osteosarcoma and Ewing sarcoma typically show skin involvement as part of widespread disease with poor prognosis, while chordoma more often has skin-only or skin-dominant metastases with slower progression and occasional long-term survival. These findings highlight the need for greater awareness among clinicians to recognize unusual skin lesions in bone sarcoma patients, potentially enabling earlier diagnosis and better management.

Background/Objectives: Cutaneous metastases from primary bone sarcomas are exceedingly rare and poorly characterized, often posing diagnostic challenges due to their atypical presentation. This systematic review aimed to describe the clinical patterns, temporal relationships, and prognostic implications of cutaneous metastases across major bone sarcoma histologies. Methods: A comprehensive literature search was conducted to identify all reported cases of cutaneous metastases from osteosarcoma, chondrosarcoma, Ewing sarcoma, and chordoma. Data on patient demographics, primary tumor site, cutaneous lesion characteristics, latency periods, synchronous metastases, morphology, and clinical outcome were extracted and analyzed descriptively. Results: 102 cases were identified, with chordoma representing the most frequent histology. Cutaneous metastases showed histology-specific patterns: osteosarcoma and Ewing sarcoma typically presented with multiple lesions in the context of widespread systemic disease and poor prognosis, whereas chordoma more often exhibited solitary or skin-dominant metastases with longer latency and occasional favorable outcomes, including complete responses after local treatment. Conclusions: Cutaneous metastases in bone sarcomas display heterogeneous behavior, with chordoma demonstrating a more indolent and potentially manageable pattern compared to other histologies. Increased clinical awareness is essential to avoid diagnostic delays and optimize management.