CLINICAL RESEARCH

 

Large Osteochondromas During Growth: A Case Series and Literature Review

 

Patricio P. Manzone,* Claudio A. Fernández,** Marta Salom,# María Emilia Moreiro,## Nuria Amarilla,§ Claudio Silveri,§§ Pablo Stoppiello,§§ Gottardo Bianchi,§§ Nicolás Casales,§§ Leticia Gaiero,§§ Pablo Amador,I Silvana Fiscina,II

Sergio InnocentiII

*Nicolás Andry” Center, Resistencia, Chaco, Argentina

**School of Medical Science, National University of La Plata, La Plata, Buenos Aires, Argentina

#Pediatric Orthopedic and Trauma Surgery Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain

##Pediatric Orthopedics and Traumatology Service, Hospital de Niños “Sor María Ludovica”, La Plata, Buenos Aires, Argentina

§Orthopedics and Traumatology Service, Hospital General “Dr. Julio C. Perrando”, Resistencia, Chaco, Argentina

§§UPOME - Musculoskeletal Oncology Unit, Universidad de la República, Montevideo, Uruguay

IOrthopedics and Traumatology Service, Hospital San Bernardo, Salta, Argentina

IIOrthopedics and Traumatology Service, Hospital Nacional de Pediatría S.A.M.I.C. “Prof. Dr. Juan P. Garrahan”, Autonomous City of Buenos Aires, Argentina

 

ABSTRACT

Introduction: Osteochondromas are the most common benign osteochondral tumors. Their size is rarely an indication for surgery, and large osteochondromas are usually reported as isolated cases. However, although rare, the potential for malignant transformation exists. We present a series of large osteochondromas in a pediatric population treated surgically, along with a review of the literature. Materials and Methods: A retrospective, multicenter cohort study was conducted in skeletally immature patients with large osteochondromas who underwent surgical treatment. Tumor volume was assessed using preoperative imaging. Demographic and surgical variables were analyzed. Results: Twenty patients (16 males and 4 females) from eight sites were included; four had multiple osteochondromatosis and the mean age at surgery was 14 years. Nineteen patients had lesions in the extremities, and one had an extraspinal osteochondroma. Four patients were asymptomatic. Magnetic resonance imaging was used to determine tumor volume; the mean volume was 65 cmS (range: 43.75–904.78 cmS). Surgical treatment included marginal resection in 10 cases, wide resection in 8, and intralesional resection in 2. Mean follow-up was 4 years and 8 months. There were two immediate postoperative complications, two late complications, and one recurrence. Conclusions: Surgical removal of large osteochondromas in the extremities and in extraspinal locations should be considered even in asymptomatic patients due to the risk of malignant transformation. Intralesional resection should be avoided because of the risk of recurrence. Marginal resection is the preferred approach, although selected cases may require wide resection with reconstruction.

Keywords: Osteochondroma; pediatric; staging; surgical treatment.

Level of Evidence: IV

 

Osteocondromas voluminosos durante el crecimiento: serie de casos y revisión bibliográfica

 

RESUMEN

Introducción: Los osteocondromas son los tumores osteocartilaginosos benignos más frecuentes. Raramente su volumen es indicación de cirugía y los osteocondromas voluminosos, en general, se comunican como casos aislados. La posibilidad de malignización, aunque excepcional, existe. Se presenta una serie de osteocondromas voluminosos en una población pediátrica tratados quirúrgicamente, y se revisa la bibliografía. Materiales y Métodos: Investigación retrospectiva de cohorte multicéntrica de pacientes inmaduros esqueléticamente con osteocondromas voluminosos operados. Se evaluó el volumen en imágenes preoperatorias. Se analizaron diferentes variables demográficas y quirúrgicas. Resultados: Se incluyó a 20 pacientes (16 varones y 4 niñas) con una edad media al operarse de 14 años, provenientes de 8 centros, 4 con osteocondromatosis múltiple. Diecinueve tenían osteocondromas en las extremidades y uno, un osteocondroma extracanal en el raquis. Cuatro eran asintomáticos. Se usaron las imágenes preoperatorias de resonancia magnética para definir el volumen; el volumen general promedio fue 65 cm3 (43,75-904,78 cm3). La cirugía incluyó resección marginal (10 casos), amplia (8 casos) e intralesional (2 casos). Tiempo medio de seguimiento: 4 años y 8 meses. Hubo 2 complicaciones posoperatorias inmediatas, y 2 complicaciones posoperatorias alejadas y una recidiva. Conclusiones: Considerar la ablación quirúrgica de osteocondromas voluminosos de extremidades y extracanalares raquídeos, aun sin síntomas, ante la posibilidad de malignización. Evitar la ablación intralesional por los riesgos de recidiva. El procedimiento adecuado es la resección marginal; algunos casos seleccionados requieren resección amplia con reconstrucción. Palabras clave: Osteocondroma voluminoso; niños; estadificación; tratamiento quirúrgico.

Nivel de Evidencia: IV

 

INTRODUCTION

Osteochondromas are the most common benign osteocartilaginous tumors1 and are typically located in the lower extremities, with an estimated prevalence ranging from 0.44% to 4.5%.2 Surgical resection is indicated when lesions are symptomatic, when associated complications are present, for cosmetic reasons, or when malignant transformation is suspected.3 Size alone is rarely an indication for surgery in skeletally immature patients.

Reports of large osteochondromas are generally limited to isolated cases, and surgical management is relatively uncommon.4–6

The aim of this study was to evaluate our own case series of large osteochondromas in a skeletally immature population undergoing surgery, to analyze their main characteristics and the treatments performed, as well as shortand mid-term outcomes, and to conduct a literature review.

 

MATERIALS AND METHODS

A multicenter, retrospective cohort study was conducted across Orthopedic and Traumatology Departments in three countries (8 sites), through review of cases recorded over the past 20 years (2004–2023).

Patients <18 years of age or skeletally immature (based on bone age), with large osteochondromas who underwent surgical treatment and had a minimum follow-up of one year, were included. To be eligible, patients were required to have osteochondromas with a volume >40 cmG; this threshold was selected because a pedunculated osteochondroma of the knee typically has a smaller volume.

Patients with intraspinal osteochondromas were excluded. However, patients with extraspinal vertebral osteochondromas without neurological risk were included if they met the specified volume criterion. Table 1 summarizes the variables analyzed in each case.

As this was a multicenter observational study, each participating institution’s Ethics Committee determined that formal approval was not required. Nevertheless, all parents, legal guardians, or patients (depending on age, clinical context, and local regulations) provided informed consent for participation in the study and for publication of their data and images, ensuring preservation of patient confidentiality.

 

Statistical Analysis

Parametric variables were analyzed using Student’s t test, and nonparametric variables using the chi-square test. Preoperative tumor volume was estimated as an approximation of the actual volume based on the best available imaging study: tumor shape was matched to the closest geometric form, and volume was subsequently calculated mathematically (Figure 1). Although these measurements were approximate rather than exact, they were close to the true values.

 

 

 

 

 

 

 

 

 

RESULTS

A total of 20 patients (16 males and 4 females) with a mean age of 14 years at the time of surgery (range 10 years 8 months-18 years) from eight sites in three countries were included (Table 2).

 

 

 

 

 

 

 

Five patients had associated conditions (4 with multiple osteochondromatosis and 1 with Down syndrome). The anatomical locations are shown in Figure 2: 12 lesions were in the lower extremities, 7 in the upper extremities, and 1 in the spine. No statistically significant differences were found between sex and age (p = 0.6), nor between sex and anatomical location (p = 0.53).

 

 

 

 

 

 

 

Four patients were asymptomatic preoperatively; in these cases, the indication for surgery was based on tumor volume or patient and family concern. In the remaining 16 cases, symptoms included pain (12 cases) (Figure 3), progressive deformity or mass (4 cases), limitation of joint motion (3 cases), and neurological symptoms (regional paresthesia in 2 cases).

 

 

 

 

 

 

 

All patients underwent plain radiographs; all but one also underwent magnetic resonance imaging (MRI), and 12 additionally underwent computed tomography (CT). MRI was primarily used to assess tumor volume. The mean tumor volume was 65 cmG (range 43.75-904.78). No statistically significant differences were found in tumor volume between sexes (p = 0.51), nor between osteochondromas of the upper and lower extremities (p = 0.27).

Only three patients underwent image-guided percutaneous biopsy prior to resection; histopathological findings were consistent with the final surgical specimen.

Ten patients were treated with marginal resection, eight with wide resection, and two with intralesional ablation. All tumors were sessile osteochondromas on histopathological examination, with no evidence of malignancy or soft tissue invasion, and a cartilage cap thickness ≥3 cm.

The most performed procedure was simple tumor resection (16 cases: 15 in the extremities and 1 in the spine), either en bloc or piecemeal; reconstruction was required in only four cases. In the spinal osteochondroma, the procedure was supplemented with arthrodesis and pedicle instrumentation, without reconstruction.

Two early minor postoperative complications occurred, both in patients with extremity osteochondromas, and both resolved completely: one case of joint stiffness and one case of transient common fibular nerve deficit. No patient required additional treatment.

The mean follow-up was 4 years and 8 months (range 1–24 years), and the mean age at follow-up was 17 years and 2 months (range 12–22 years). Two late complications were observed: one case of proximal humeral pseudarthrosis that was not treated because it did not affect activities of daily living (patient with Down syndrome and significant cognitive impairment) (Figure 4), and one case of persistent pain in the adductor region, which resolved with injections and tenotomies.

 

 

 

 

 

 

Considering both early and late complications together, for extremity osteochondromas (n = 19), no statistically significant differences were found between upper and lower extremities (p = 0.53).

One recurrence occurred after incomplete resection, and the patient received expectant management (case 18). Two patients had residual sequelae: one with limited active shoulder abduction (case of proximal humeral pseudarthrosis), and another with mild right thoracic scoliosis (12°), secondary to ablation; neither required further treatment.

 

DISCUSSION

The surgical indications for excision of osteochondromas in the immature skeleton are well established in the literature.7 Tumor volume alone does not justify surgical resection; however, an increase in size after completion of skeletal growth has been associated with a higher risk of malignant transformation, although this relationship has not been clearly defined.7

We did not identify published case series of large osteochondromas treated surgically similar to this cohort, nor reliable methods for volumetric measurement on imaging studies. Therefore, preoperative tumor volume (CT, MRI) was estimated by approximating tumor morphology to the closest geometric shape.

Large osteochondromas of the extremities usually produce symptoms depending on their location; however, four patients in our series were referred while asymptomatic after incidental detection of a mass. In contrast, spinal osteochondromas are typically exophytic lesions arising from the posterior elements (Case 9, Table 2; Figure 5) and extending outside the spinal canal. They usually present as a palpable mass and rarely cause symptoms or neurological compromise.8 In some cases, they may lead to secondary deformity.9 However, growth toward the spinal canal, regardless of size, may result in severe neurological deficits, particularly in the cervical and thoracic regions.10

Biopsy is generally not required in cases of typical osteochondromas. In three patients in our series, biopsy was performed due to suspicion of malignant transformation based on rapid growth, although cartilage cap thickness and morphology remained within benign parameters.

Although spontaneous regression of osteochondromas has been described in children,11 complete excision with free margins remains the treatment of choice.

 

 

 

 

 

 

In large or rapidly growing tumors, the main concern, although uncommon, is malignant transformation into chondrosarcoma; osteosarcoma and other neoplasms have also been reported.12,13 The risk of malignant transformation to chondrosarcoma is estimated to be <1% in solitary osteochondromas and 2–5% in multiple osteochondromatosis.14,15 Four patients in our series had multiple osteochondromatosis. Although malignant transformation is more common in adults, pediatric cases have been reported;13 secondary chondrosarcomas account for more than half of cases in children and adolescents.15

In addition to tumor growth and multiplicity, the literature consistently highlights an increased risk of malignant transformation in lesions located in the spine and in the girdles (shoulder and pelvic), as well as in recurrent tumors.15

The differential diagnosis between osteochondroma and low-grade chondrosarcoma is based on clinical presentation (pain and progressive enlargement suggest malignancy) and imaging findings: size >5 cm, irregular margins, cortical disruption, soft tissue invasion, and cartilage cap thickness >2–3 cm should raise suspicion of malignant transformation.3,16 We consider MRI an essential imaging modality for this evaluation.

Rapid tumor growth and a large mass in skeletally immature patients support surgical excision, even in the absence of symptoms. When malignant transformation is suspected, wide resection should be performed.17,18 Image-guided percutaneous biopsy may not be representative in large tumors, as it may miss areas of histological atypia.19 Furthermore, the differential diagnosis with low-grade chondrosarcoma is often challenging, which reinforces the indication for wide surgical resection.16

Most cases in this series were symptomatic or showed rapid growth, justifying surgical treatment. Four asymptomatic patients underwent surgery due to tumor volume and family concern.

There is no consensus on classifying osteochondromas of the extremities as active or aggressive according to the Enneking system; however, wide resection is generally accepted for aggressive lesions and marginal resection for active ones,20 and marginal resection is adequate for most osteochondromas.7 Wide resections may require reconstruction and tailored osteosynthesis (cases 1, 2, 3, and 4, Table 2).

In this cohort, the decision to perform wide resection was based on the following principles: (1) in very large osteochondromas, limited resection may fail to include occult atypical areas;18 (2) as all tumors were sessile, margins were established through healthy tissue to reduce the risk of recurrence; and (3) when the tumor base involves a large portion of the bone circumference, excision may result in postoperative structural weakness or spinal instability (cases 1, 2, 3, 4, and 9; Figures 3, 4, and 5). Therefore, associated osteosynthesis with reconstruction or arthrodesis is essential in these cases.

In general, long-term functional outcomes are excellent for osteochondromas around the knee treated with marginal resection alone (cases 5, 6, and 13).21 However, resection of osteochondromas located at the proximal fibula carries a risk of injury to the common fibular nerve (Figure 6).22 One patient in our series developed a transient deficit following wide resection (case 14).

 

 

 

 

 

 

We found no reports describing recurrence or prolonged postoperative pain in proximal humeral osteochondromas. However, one patient in our series developed proximal humeral pseudarthrosis following a postoperative fracture, despite osteosynthesis and reconstruction (Figure 3). In such cases, intramedullary nailing appears to be a more appropriate option (Figure 7).5

 

 

 

 

 

In general, symptom resolution exceeds 90% when resection is complete in limb osteochondromas.23 Intracanal spinal osteochondromas frequently cause neurological deficits, even when small. In such cases, the indication for surgery depends on location rather than size.24

The postoperative recurrence rate is reported to be <2% after complete resection.3 The only recurrence in our series occurred after intralesional resection (case 18; volume 46.8 cmG). The patient with a large exophytic thoracic vertebral osteochondroma (case 9; volume 103 cmG) showed no recurrence (Figure 5). Recurrence does not appear to be related to Enneking staging system stage, as it has been described even in latent lesions.25 These findings suggest that recurrence is more closely related to intralesional resection than to tumor volume or stage. The main limitations of this study are its retrospective design and the relatively small sample size, despite its multicenter nature. However, this cohort is highly specific, involving large osteochondromas in skeletally immature patients, and the number of cases appears sufficient for analysis. We found no comparable studies; most published data consist of case reports. The international multicenter nature of this series, including 20 patients, reflects both the rarity of large osteochondromas and current variability in diagnostic and therapeutic approaches.

 

CONCLUSIONS

Surgical resection of large osteochondromas of the extremities should be considered, particularly those located in the girdles (shoulder and pelvic) or in proximal regions, as well as large extracanal spinal osteochondromas, even in the absence of symptoms, given the potential for malignant transformation.

Intralesional resection of large osteochondromas should be avoided due to the risk of recurrence or residual tumor. Marginal resection is usually sufficient; however, in selected cases, wide excision may be indicated.

 

 

 

 

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C. A. Fernández ORCID ID: https://orcid.org/0000-0003-2350-3885

M. Salom ORCID ID: https://orcid.org/0000-0002-8626-2401

M. E. Moreiro ORCID ID: https://orcid.org/0009-0000-5590-9738

N. Amarilla ORCID ID: https://orcid.org/0009-0009-9432-7605

C. Silveri ORCID ID: https://orcid.org/0000-0002-2607-7749

P. Stoppiello ORCID ID: https://orcid.org/0000-0003-2085-6968

G. Bianchi ORCID ID: https://orcid.org/0000-0001-8222-4435

N. Casales ORCID ID: https://orcid.org/0000-0003-0318-8654

L. Gaiero ORCID ID: https://orcid.org/0000-0002-1182-1627

P. Amador ORCID ID: https://orcid.org/0009-0001-2888-7569

S. Fiscina ORCID ID: https://orcid.org/0000-0003-2655-4063

S. Innocenti ORCID ID: https://orcid.org/0000-0001-5650-1056

 

Received on April 22nd, 2025. Accepted after evaluation on September 26th, 2025 • Dr. PATRICIO P. MANZONE • manzonepatricio@hotmail.com • https://orcid.org/0000-0002-3987-267X

 

How to cite this article: Manzone PP, Fernández CA, Salom M, Moreiro ME, Amarilla N, Silveri C, et al. Large Osteochondromas During Growth: A Case Series and Literature Review. Rev Asoc Argent Ortop Traumatol 2026;91(2):92-102. https://doi.org/10.15417/issn.1852-7434.2026.91.2.2156

 

 

Article Info

Identification: https://doi.org/10.15417/issn.1852-7434.2026.91.2.2156

Published: April, 2026

Conflict of interests: The authors declare no conflicts of interest.

Copyright: © 2026, Revista de la Asociación Argentina de Ortopedia y Traumatología.

License: This article is under Attribution-NonCommertial-ShareAlike 4.0 International Creative Commons License (CC-BY-NC-SA 4.0).