Osteochondromas are the most common benign bone tumors, accounting for approximately 35% of all benign bone tumors ^[1]. They commonly occur during the growth period, with a peak incidence between the ages of 10 and 20 years. Osteochondromas typically involve the metaphysis of long bones. However, their occurrence in the distal radius is rare, and presentation as carpal tunnel syndrome (CTS) symptoms is even rarer, especially in children ^[2]. CTS is a common medical condition that affects the hand and wrist. It occurs when the median nerve, which runs from the forearm to the hand, becomes compressed or irritated as it passes through the carpal tunnel, a narrow passageway in the wrist surrounded by bones and a tough retinaculum. It is most commonly seen in individuals between 30 and 60 years old. Several risk factors contribute to the development of CTS. These include repetitive hand and wrist motions, work-related factors, anatomical variations, underlying health conditions (such as rheumatoid arthritis, diabetes, and hypothyroidism), pregnancy, obesity, and wrist trauma or injury. The presence of an osteochondroma at the distal end of the radius can lead to the development of CTS through several mechanisms. First, the tumor can directly compress the median nerve as it traverses the carpal tunnel. This compression leads to the typical symptomatology, including pain, numbness, and tingling in the thumb, index, and middle fingers ^[3]. The nerve compression can also result in weakness in grip strength, which was observed in this case. In addition to direct compression, the growth of the osteochondroma can cause mechanical impingement on the surrounding structures within the carpal tunnel, such as the flexor tendons. This impingement further exacerbates the compression of the median nerve. The inflammation and swelling resulting from the mechanical impingement can increase the pressure within the carpal tunnel, amplifying the compression ^[4]. Diagnosing osteochondroma-associated CTS often involves a comprehensive evaluation, including clinical assessment, radiographic imaging, and electrophysiological studies. Radiographs are typically the initial diagnostic tool, providing valuable insights into the presence and characteristics of the bony outgrowth. In some cases, additional imaging modalities such as magnetic resonance imaging (MRI) and computed tomography (CT), may be required to assess the extent of the tumor and its relationship to surrounding structures and visualize and measure the cartilage cap. Treatment for osteochondroma-associated CTS generally involves surgical intervention. The primary objective of surgery is to remove the osteochondroma, thereby relieving the compression on the median nerve. Following surgery, rehabilitation is essential to restore hand function. This typically includes hand therapy and splinting to optimize recovery and promote optimal growth and development in affected children. The primary message of this case report is to raise awareness about the occurrence of osteochondromas in uncommon locations, such as the distal end of the radius, and their potential to cause CTS. By highlighting this unique case, the report emphasizes the importance of early recognition and appropriate surgical management to alleviate symptoms, prevent long-term complications, and restore hand function.

An 8-year-old female came to our outpatient department with complaints of progressive pain, tingling, and numbness in her right hand for 6 months. The symptoms were exacerbated during activities requiring fine motor skills, such as writing or drawing. There was no significant history. Examination revealed tenderness over the distal end of the right radius, and Tinel’s sign was positive over the carpal tunnel area. The patient exhibited decreased sensation over the thumb, index, and middle fingers. Motor strength was preserved, and there were no signs of muscle atrophy. The contralateral hand and upper extremities were normal. Radiographic imaging of the right hand revealed a well-defined bony outgrowth from the radius’s distal end, consistent with an osteochondroma (Fig. 1). An MRI of the right wrist was performed to assess the extent of tumor involvement and evaluate the adjacent soft tissues. MRI revealed a lobulated bony outgrowth (~20.5 × 17 × 12 mm) with a cartilaginous cap (~3.8 mm) arising from the distal metaphysis of the radius and protruding medially (Fig. 2). CT revealed a bony outgrowth from the surface of the distal end of the radius, continuous with the underlying bone (Fig. 3). Considering the patient’s symptoms, surgical excision of the osteochondroma was planned. Under general anesthesia, a volar approach to the distal end of the radius was used. A longitudinal incision was made over the volar aspect of the wrist, and careful dissection was performed to expose the osteochondroma (Fig. 4). It was found to cause a mass effect over the adjacent flexor muscles with significant edema. The mass was then meticulously dissected from the surrounding soft tissues and sent for histopathological examination. The closure was done in layers, and a below-elbow slab was given for 4 weeks to prevent a pathological fracture.

Following the surgical excision of the osteochondroma, the patient experienced immediate relief from pain and tingling sensations. Post-operative radiographic imaging confirmed the complete excision of the tumor (Fig. 5).

Histopathological examination confirmed the diagnosis of osteochondroma. The patient underwent a short physical therapy and rehabilitation period to regain hand strength and mobility. At the 1-year follow-up, the patient remained symptom-free, with complete resolution of her CTS (Fig. 6).

CTS is a relatively uncommon condition in children, and when it occurs, it is often associated with underlying factors such as congenital anomalies, trauma, or systemic diseases. However, in this unique case, an 8-year-old female presented with CTS caused by osteochondroma located at the distal radius. This atypical and rare case highlights the importance of considering unusual underlying factors when evaluating pediatric patients with CTS. Diagnosing osteochondroma-associated CTS in children requires a comprehensive evaluation. The initial step often involves a thorough clinical assessment, including a detailed history and examination. During the physical examination, decreased sensation in the affected fingers and weakness in grip strength can be observed. However, given the rarity of this condition, it may not be initially suspected. A comprehensive literature search was conducted in major scientific databases and identified limited cases reporting an osteochondroma presenting as CTS (Table 1). The age range of affected patients varied from 12 to 78 years, with only one pediatric case reported.

A 12-year-old male with a solitary mass on the volar aspect of the distal radius who presented clinically with CTS was reported by Kale et al. ^[11] Excision biopsy confirmed the diagnosis of osteochondroma and also relieved all symptoms. Though there are few reports of CTS due to osteochondroma in the literature, the current case is the youngest, which makes it unique in its presentation and worth reporting. By presenting this case, we hope to contribute to the existing literature and enhance clinicians’ understanding of the assessment and management of similar cases in the future.

In conclusion, osteochondroma of the distal end of the radius can uncommonly present as CTS in pediatric patients, even as young as an 8-year-old female. Although osteochondromas are typically benign bone tumors, their presence near the carpal tunnel can lead to compression of the median nerve, resulting in CTS symptoms.

Early intervention can help alleviate symptoms, preserve hand function, and ensure optimal development in affected pediatric patients.