# Soft tissue recurrence in giant cell tumor of Bone: A comprehensive review of pathogenesis, imaging features, and clinical management

## TL;DR

Soft-tissue recurrence in giant cell tumors of bone is rare but distinct, with specific imaging patterns and treatment challenges requiring surgical excision and close monitoring.

## Contribution

This paper provides a comprehensive review of soft-tissue recurrence in GCTB, emphasizing its unique clinical and imaging features and management strategies.

## Key findings

- Soft-tissue recurrence occurs in 2–3% of GCTB cases, typically within the first postoperative year.
- Imaging reveals three distinct patterns: peripheral 'eggshell' ossification, central nodular calcification, and purely soft-tissue lesions.
- Surgical excision with clear margins is the main treatment, but up to 60% of patients experience multiple recurrences.

## Abstract

•Soft-tissue recurrence (STR) occurs in 2–3% of giant cell tumors of bone (GCTB), usually within the first postoperative year.•Major risk factors include curettage procedures, cortical breaches, and pathological fractures, which facilitate tumor cell seeding.•Imaging reveals three characteristic patterns: peripheral “eggshell” ossification, central nodular calcification, and purely soft-tissue lesions.•Histology and H3F3A mutation status in STR mirror primary GCTB, supporting its nature as a true recurrence.•Complete surgical excision with negative margins remains the mainstay of treatment, ensuring excellent functional outcomes.•Up to 60 % of patients experience multiple STRs, underscoring the need for close surveillance during the first 24 months.•Systemic therapies (denosumab, bisphosphonates) may be used off-label in selected cases, and radiotherapy is contraindicated due to malignant transformation risk.

Soft-tissue recurrence (STR) occurs in 2–3% of giant cell tumors of bone (GCTB), usually within the first postoperative year.

Major risk factors include curettage procedures, cortical breaches, and pathological fractures, which facilitate tumor cell seeding.

Imaging reveals three characteristic patterns: peripheral “eggshell” ossification, central nodular calcification, and purely soft-tissue lesions.

Histology and H3F3A mutation status in STR mirror primary GCTB, supporting its nature as a true recurrence.

Complete surgical excision with negative margins remains the mainstay of treatment, ensuring excellent functional outcomes.

Up to 60 % of patients experience multiple STRs, underscoring the need for close surveillance during the first 24 months.

Systemic therapies (denosumab, bisphosphonates) may be used off-label in selected cases, and radiotherapy is contraindicated due to malignant transformation risk.

Giant cell tumor of bone (GCTB) is a benign but locally aggressive neoplasm with a high risk of recurrence. Among its patterns of relapse, soft-tissue recurrence (STR) is an uncommon but clinically significant entity, often presenting as ossified or non-ossified perilesional nodules. Despite its rarity, STR poses diagnostic and therapeutic challenges that require clarification.

A comprehensive literature review was performed across PubMed, Embase, and Google Scholar from 1980 through January 2025, focusing on the epidemiology, pathogenesis, imaging features, histopathology, management, and outcomes of STR in GCTB. Case reports, series, and retrospective studies explicitly distinguishing STR from intraosseous recurrence were included, and findings were synthesized narratively.

STR occurs in approximately 2–3 % of GCTB cases, typically within 6–12 months after surgery. Major risk factors include curettage procedures, pathological fractures, cortical breaches, and unrecognized microscopic soft-tissue extension. Imaging reveals three distinct patterns: peripheral “eggshell” ossification, central nodular calcification, and purely soft-tissue lesions. Histology mirrors primary GCTB, often with osteogenic metaplasia, while molecular testing confirms retention of H3F3A mutations. Surgical excision with clear margins remains the mainstay of treatment, yielding excellent functional outcomes. However, up to 60 % of patients experience multiple recurrences, highlighting the need for vigilant surveillance. Systemic agents such as denosumab or bisphosphonates remain investigational, and radiotherapy is generally contraindicated due to malignant transformation risk.

STR represents a rare but distinct subset of GCTB recurrences. Awareness of risk factors, early imaging-based detection, and complete surgical excision are critical for optimal outcomes. Further multicenter studies are required to define surveillance protocols, validate molecular predictors, and clarify the role of systemic therapy in this challenging condition.