Navigating the unusual: A case of osteoid osteoma on the external skull table

INTRODUCTION

Osteomas are rare, benign bone tumors that typically develop in the paranasal sinuses and skull. These slow-growing lesions are often asymptomatic but may cause functional or cosmetic issues when they grow large enough. Surgical removal is the treatment of choice, particularly when the osteoma interferes with normal function, leads to neurological symptoms or poses aesthetic concerns.^[1] While osteomas can be removed using various surgical techniques, the use of conventional tools like a chisel and mallet remains effective in certain cases, especially when the tumour is easily accessible. This case report presents the successful excision of an osteoma from the external table of the skull using this traditional approach.^[2]

CASE REPORT

A 48-year-old female patient presented with a longstanding swelling over the right side of her forehead. The swelling was initially pea-sized when first noticed about 20 years ago and had gradually increased over time. The patient had been undergoing Ayurvedic treatment for joint pain during the progression of the swelling, but no other significant medical history was noted.

On clinical examination, a swelling approximately 2 × 2 cm in size was observed over the right frontal region [Figure 1]. The lesion was well-defined, non-tender and bony hard in nature. It was firm, non-fluctuant and fixed to the underlying bone. There were no signs of inflammation or skin changes over the swelling, and the overlying skin appeared normal.

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Figure 1:

Pre-operative image showing the frontal swelling indicative of the osteoma, highlighting the area to be surgically accessed for excision. The lesion is clearly demarcated for accurate planning of the incision and approach.

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Incision and exposure

A curvilinear incision was made over the dome of the swelling to ensure optimal exposure of the lesion while minimising post-operative scarring. The subcutaneous tissues and underlying soft tissues were carefully dissected to access the periosteum, which covered the bone and the lesion [Figure 2].

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Figure 2:

Intraoperative image showing the curvilinear incision made over the dome of the swelling, with careful dissection of the subcutaneous and soft tissues to expose the periosteum covering the osteoma.

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Excision

The osteoma was excised, and careful attention was paid to ensure the complete removal of the lesion while preserving the integrity of the surrounding bone. After excision, the bony bed was inspected to confirm that no residual growth remained [Figure 3].

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Figure 3:

Post-excision image of the osteoma confirming the complete removal of the lesion.

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Closure

The wound was closed in layers. The periosteum was approximated using absorbable sutures, and the skin was closed with a subcuticular stitch using 3-0 Vicryl to minimise scarring and provide a neat appearance. The closure was done carefully to ensure optimal healing and cosmetic results [Figure 4].

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Figure 4:

Image showing the final closure of the wound in layers, with the periosteum approximated using absorbable sutures and the skin closed with a subcuticular stitch using 3-0 Vicryl for optimal cosmetic results.

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DISCUSSION

Osteomas are slow-growing, benign osseous tumours that typically affect the paranasal sinuses and skull. They are usually found by chance during radiological examinations and are asymptomatic. However, depending on their size and location, osteomas can occasionally exhibit clinical signs such as pain, swelling or neurological abnormalities. The frontal and parietal bones are most frequently affected, and osteomas frequently occur on the external table of the skull. The excision of these tumours is sometimes recommended for cosmetic purposes, to relieve symptoms or to avoid potential problems, including infection or strain on underlying structures, even though they seldom develop into malignant transformation.^[3]

In this case report, we present a patient who had an osteoma over the frontal area on the external table of the skull. Clinical assessment was used to identify the mass, and radiographic imaging was used to confirm it. The imaging showed that the mass had the characteristic radiopaque look of an osteoma. A chisel and mallet technique, a time-honoured method that can still be successful and dependable in some situations, particularly in superficial skull lesions, was used to execute the surgical excision.^[4]

Using a chisel and mallet gives the surgeon direct mechanical control, which is one benefit. The chisel enables the osteoma to be removed more slowly and carefully than power instruments, which might produce too much heat and run the danger of unintentionally damaging nearby soft tissues. The chisel is given a regulated force by the mallet, which facilitates the removal of the tumour without needlessly injuring the surrounding cranium. Furthermore, even in situations when access is restricted or the osteoma is located close to significant anatomical markers like the dural layer or major blood arteries, the chisel and mallet technique can be applied successfully.^[5]

The recurrence rate of osteoid osteomas following complete surgical excision is extremely low. Literature suggests recurrence occurs in <1% of cases when the lesion is entirely removed, particularly when the nidus is fully excised. This supports the long-term effectiveness of surgical management for such benign skull tumours and correlates with the favourable outcome observed in this case.

CONCLUSION

Surgically excising osteomas from the skull’s external table with a chisel and mallet method is still a safe, dependable and efficient method, especially for lesions that are easily accessible and clearly delineated. Even though there are many contemporary methods for removing bone, the old-fashioned chisel and mallet approach still has its uses in some therapeutic settings because it provides good control and a low risk of problems. The effectiveness of this approach in treating benign skull tumours is demonstrated by this case, which offers positive results with low morbidity.