Osteochondroma below the Infraorbital Rim - A Case Report

Abstract

Rationale:

Osteochondroma, a benign bony neoplasm that can develop in any part of the body, commonly appears in the ends of the long bones. It can also occur in the craniofacial region such as mandibular condyle and coronoid region. We describe the clinical presentation, diagnostic process, surgical management and post-operative outcomes in a 34-year-old male patient. Only few cases are reported in literature till now and often are mistaken as bony exostosis.

Patient Concerns:

The patient sought medical attention due to the cosmetic concerns.

Diagnosis:

Through clinical palpation and radiological interpretation. Provisional diagnosis of bony exostosis was made, which was later confirmed as osteochondroma on histopathological examination.

Treatment:

Surgical removal of the bony growth was performed.

Outcomes:

Follow-up was uneventful with no evidence of recurrence.

Take-away Lessons:

The report aims to raise awareness about this manifestation and to encourage further research to better understand aetiology, management and outcomes of osteochondroma in unusual locations.

INTRODUCTION

Osteochondromas are benign tumours characterised by the overgrowth of the bone and cartilage typically observed in the long bones, such as femur or humerus. They develop because of the epiphyseal cartilage outgrowth into the surrounding tissues. This theory, however, is unable to account for the presence of this tumour in the bone and soft tissue. The exact aetiology is still under controversy.[1,2]

The size of osteochondromas vary, ranging from small nodules to substantial bony protrusions. Large osteochondromas may cause aesthetic concerns, tending individuals to seek medical attention.[1] This case report presents a unique occurrence of osteochondroma below the infraorbital rim, which was misdiagnosed as bony exostosis.

CASE REPORT

A 34-year-old male patient presented with a swelling below the left eye for five years. The patient reported a history of asymptomatic swelling which had gradually increased in size and was causing discomfort when touched and during facial expression. In addition, the patient was distressed about the noticeable asymmetry of his face due to the growth. The history of trauma to the region was absent.

On clinical examination, there was the presence of a well-defined, firm and non-tender bony protuberance measuring approximately 2 cm in diameter, located below the left infraorbital rim slightly laterally extending along the zygomatic arch [Figure 1]. The overlying skin appeared normal without any signs of inflammation. The patient’s medical history was unremarkable, with no family history of similar conditions. The clinical presentation raised suspicions of bony exostosis, although rarity of condition below the infraorbital rim necessitated a comprehensive diagnostic evaluation.

Figure 1.

Bony growth in relation to the infraorbital rim

An imaging study with computed tomography scan was performed to visualise the extent and characteristics of bony prominence; the images confirmed a localised bony growth, distinct from the underlying zygomatic bone, below the left infraorbital rim extending to the zygomatic arch [Figure 2]. No signs of bone erosion or invasion into the adjacent structures was noted. Considering the patient’s aesthetic concerns and potential for growth progression, decision was made to surgically excise the bony growth. Routine laboratory investigations were within the normal limits. The patient provided informed consent, and the surgical procedure was performed under general anaesthesia.

Figure 2.

Computed tomography scan visualising the extent of growth

The patient was aseptically prepared, and tarsorrhaphy was done for the protection of the cornea during the operative procedure. Infraorbital incision was placed, and careful soft tissue dissection was carried out to expose the growth without causing damage to the adjacent structures [Figure 3]. The bony growth was meticulously removed from its pseudojoint with zygomatic bone using a handpiece with bur and bone chisel [Figure 4]. Active bleeding points on the bony surface after the removal were identified and cauterised. The bone was smoothened using a bone file. Debridement was done using saline to remove the bony debris [Figure 5]. Wound edges were aligned, and suturing was carried out (skin as well as subcutaneous layer) in such a way to minimise scarring and achieve an optimal cosmetic outcome [Figure 6]. No major bony defects were present that needed reconstruction. No topical medicine was prescribed for the sutured wound postoperatively.

Figure 3.

Infraorbital incision to expose the site

Figure 4.

Bony specimen after the removal

Figure 5.

Surgical site after the debridement

Figure 6.

Suturing

The specimen was sent for histopathological examination, and the analysis confirmed the features of osteochondroma revealing cartilaginous cap with underlying mature bone consistent with benign osteochondral proliferation. The margins of the excision were free from any malignant features. Post-operative follow-up of the patient showed uneventful healing with minimal swelling and discomfort in relation to the surgical site, and the patient expressed satisfaction with the aesthetic outcome and alleviation of discomfort [Figure 7]. There was no signs of recurrence or complications during the follow-up period.

Figure 7.

Post-operative follow-up

DISCUSSION

Osteochondromas are generally benign, firm, painless, non-tender, fixed or sessile growths; however, they require surgical intervention when they cause symptoms or aesthetic concerns for affected individuals or when they cause discomfort or compression to the surrounding structures. The occurrence of osteochondromas below the infraorbital rim is an extremely rare finding, with little literature evidence.[1,2]

The aetiology of osteochondromas, also known as osteocartilaginous exostoses, is not entirely understood, but is believed to involve a combination of genetic and developmental factors. Osteochondromas can be solitary (85%) or multiple osteochondromas (15%). Sizes can vary from few millimetres to several centimetres (<5 cm).[3,4]

Solitary osteochondromas are single bony growths that emerge from the metaphysis of the long bones such as femur, tibia or humerus or are present in the facial region (mandible and temporal bone area). They account for the majority of osteochondroma cases. Solitary osteochondromas are often asymptomatic and usually discovered incidentally. Symptoms when present may include a painless palpable mass, pain due to irritation to the surrounding tissues or mechanical issues such as restricted movement when present in areas like the mandible.[5]

Multiple osteochondromas are present in hereditary multiple osteochondromatosis. It is a genetic disorder inherited in an autosomal-dominant pattern and associated with mutations in EXT1 and EXT2 genes. Symptoms are similar to solitary osteochondromas but more severe due to multiple lesions. The patients experience more significant deformities, joint problems.[5] Developmental abnormalities in the growth plate (physis of the bones) can lead to the formation of bony growth with cartilaginous cap. Some osteochondromas may be triggered or exacerbated by trauma or injury to the affected bone.[5]

Diagnosing osteochondromas typically involves a thorough clinical examination, including palpation of the affected area. Imaging studies such as X-rays and cone-beam computed tomography are often performed to visualise and confirm the presence and characteristics of bony growth. Magnetic resonance imaging may be used to evaluate the extent and potential involvement of the adjacent soft tissues.[6]

The differential diagnosis of osteochondromas includes other bony growths such as bony exostosis, fibrous dysplasia, ossifying fibroma, chondroblastomas, enchondroma, periosteal chondroma, osteochondromyxoma, chondromyxoid fibroma and osteomas. Benign chondrogenic tumours such as osteochondromas and enchondromas have higher prevalence when compared to malignant tumours such as chondrosarcomas. Malignant bony tumours such as osteosarcomas or metastatic lesions should also be ruled out to ensure accurate diagnosis and appropriate management. Any bony growth with pain symptoms and increase in size >5 cm, showing bone expansion, should be considered in differential diagnosis as a malignancy. If there is penetration into the soft tissues, a differential diagnosis of chondrosarcoma should be considered.[7]

The management of osteochondromas depends on several factors including the size, its impact on the adjacent structures, patient symptoms or aesthetic concerns. Asymptomatic cases may not require immediate treatment and can be managed with regular monitoring. Although rare, there is a risk of osteochondromas transforming to chondrosarcoma. Regular monitoring and prompt biopsy of suspicious lesions is important; excision of osteochondromas along with corrective surgery to address the deformities is commonly employed as the treatment option if osteochondroma causes significant pain, functional impairment, nerve or vascular compression or cosmetic concerns. In case of multiple hereditary osteochondromatosis, identification of mutations in EXT1 and EXT2 genes to confirm the diagnosis is important.[5]

Surgical excision, as performed in this case, is the primary treatment modality for symptomatic or cosmetically concerning bony osteochondromas. The goal is to achieve complete removal of osteochondroma by careful removal of the growth with preservation of integrity of the zygomatic bone and surrounding tissues when minimising complications and ensuring favourable post-operative outcomes.[8,9] Histopathological evaluation is essential for confirming the diagnosis, ruling out malignancy and understanding the growth’s cellular composition.[1]

The prognosis for individuals with osteochondromas is generally favourable after successful surgical intervention. Most patients experience relief from symptoms and are satisfied with aesthetic results. Follow-up evaluations are crucial to monitor for any signs of recurrence and ensure long-term stability of the zygomatic bone.[9]

CONCLUSION

Successful surgical management and favourable aesthetic outcomes demonstrate the importance of early diagnosis and successful surgical outcomes. Further research and reporting of similar cases are necessary to broaden our understanding of this uncommon variant and its management.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.