Background

Giant cell tumour (GCT) of bones is one of the most common benign bone tumours and usually involves the metaphysis-epiphysis region of long bones, especially the distal femur, although occurrences in other regions have been reported.1 The hand is one of the rarest sites for bone GCT, but it has a high recurrence rate and can easily be misdiagnosed.2 3 Careful examination, complete investigation and optimum follow-up scheduling are key to avoiding a misdiagnosis.

Case presentation

A healthy, active, 49-year-old woman initially presented to our team in January 2017 with a history of pain, tenderness and swelling in the left middle finger following a minor trauma to her right hand 1 year previously. She denied any history of constitutional symptoms. Physical examination showed a swollen and tender mass with firm consistency at the middle phalanx of the middle finger of the left hand. Range of motion of the adjacent joints (distal interphalangeal and proximal interphalangeal joints) was preserved and capillary refill time was normal.

Investigations

Plain radiography showed a geographic osteolytic lesion on the shaft of the middle phalanx of the left middle finger with a well-defined sclerotic border; no periosteal reaction or fracture line were seen (arrow, figure 1). The long-term onset of clinical symptoms with occasional pain was compatible with repeated fracture and healing of the sclerotic rim. MRI was requested for local extension and primary carcinoma identification. Evaluation showed a hypointense solid intramedullary lesion with hyperintense surrounding soft tissue. Enchondroma with pathological fracture was considered the most likely diagnosis, and the patient was scheduled for follow-up in 6 months. At that 6-month follow-up, the patient showed no improvement in the swelling or pain. A plain radiograph showed progression of an expansile osteolytic lesion with articular involvement (arrow, figure 2) indicating an aggressive tumour with cortical extension and articular involvement. Repeat chest radiographs showed no evidence of pulmonary metastasis. An incisional biopsy was performed in July 2017, 6 months after the initial visit. Histopathology was compatible with giant cell bone tumour and was classified as Campanacci stage III.

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Figure 1

First visit: a well-defined geographic lesion with sclerotic border resembling enchondroma was described.

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Figure 2

Six-months follow-up: an expansile geographic osteolytic lesion was identified by radiographic study.

Differential diagnosis

Based on the Initially benign characteristics and epidemiology, there was a differential diagnosis at the 6-months follow-up. Based on radiography and the history of progression, GCT, chondrosarcoma (secondary to enchondroma) and acrometastasis were considered due to the tumour’s aggressiveness.

Treatment

Middle phalanx resection and interphalangeal joint arthrodesis with iliac bone graft were performed following the diagnosis. Since the lesion involved nearly the entire middle phalanx with some local invasion, tumour resection was chosen rather than the standard extended curettage to help insure there was no residual tumour. No immediate complications were observed. Since there was no evidence of metastasis, no systemic treatments were scheduled for this patient.

Outcome and follow-up

At the 1-year follow-up, the patient’s middle phalanx was pain-free with some functional attenuation due to phalangeal fusion. A plain radiograph revealed a union of the middle phalanx with no sign of GCT recurrence (figure 3).

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Figure 3

One-year follow-up: radiographic view of fused middle finger with no sign of recurrence.

Discussion

GCT of bone is one of the most common benign or locally aggressive bone tumours, especially in the epiphysis region.2 Peak incidence of GCT occurs in the third and fourth decades of life.4 GCT in the hand has been noted as a rare location, with only 2% of reported cases.2 3 Early radiographic signs can resemble enchondroma and are likely to be misdiagnosed by general practitioners or even by orthopaedists. However, the aggressive behaviour, for example, the progressiveness and painfulness, can help distinguish GCT from other benign tumours. Additionally, more rapid growth and a higher recurrence rate are observed in GCT in the hand region compared with conventional types.3 Clinical presentation includes pain with or without signs of inflammation. Since the natural history of this tumour is quite benign, most cases will have insidious and progressive localised pain.5 Range of motion can be limited if the lesion lies adjacent to a joint. Some cases, however, present with a pathological fracture but with no prior history.5 6 Once GCT of bone is suspected, plain radiography is the easiest and should be the first means of investigation. Radiography can highlight the expanding zone of radiolucency, usually in the end of a long bone between the metaphysis and the epiphysis. The lesions can be either well or poorly marginated without a sclerotic border. Periosteal reaction is rarely seen.1 Campanacci described three grades of disease using radiological findings. At the higher grade, a positive correlation with aggressiveness and high recurrence rate has been reported. Grade I is defined as having a well-defined margin with thin rim. In grade II, lesions involve a larger area and extend to the cortical layer without the breakage which is the defining feature of grade III.7

MRI is the tool of choice for investigating GCT since it is capable of demonstrating the extent of the lesion as well as identifying any extraosseous lesions. CT is also useful in structural evaluation. The thin sclerotic rim, visible in a CT scan, helps distinguish GCT from malignancy. To date, even with the most advanced techniques, imaging of features in GCT of bone in the hand is not sufficiently specific; images of GCT can resemble many other kinds of bone lesions, especially enchondroma which are more common in the hand region. For that reason, tissue diagnosis is mandatory.1 7 Gross pathology characteristics of GCT of bone usually include a dark brown colour and soft to firm consistency with an area of fibrosis and osteoid production. Blood-filled cystic lesions can be seen. The histopathological hallmark of GCT of bone is the classic multinucleated giant cells of the osteoclast from which osteoclastoma derives its name. Mitotic activity can be seen without nuclear atypia. Clinical presentation, imaging and tissue examination results should be correlated in making a diagnosis. A chest radiograph should be routinely requested as a preoperative requirement, and to check for pulmonary metastasis. CT can also help detect such lesions. Extended curettage with a high-speed burr is currently the treatment of choice for GCT.8 In addition, multiple modalities of cavitary adjuvant treatment are now widely used to achieve adequate local control, with a 6%–25% recurrence rate.8–10 Thermal adjuvants include freezing, eg, with liquid nitrogen, and heating, eg, with polymethyl methacrylate and argon beam cauterisation. Cytotoxic agents can be used as chemical adjuvants, eg, phenol.1 En bloc resection is reserved as the treatment of last resort in cases of uncontrolled recurrence.11

The local recurrence rate is highest in the first 24 months following treatment, ranging from 4% to 30%.12 Follow-up should be scheduled with serial physical examination and imaging of the surgical site as well as a routine chest radiograph. GCT of bone in the hand region has been recognised as having a higher recurrence rate compared with more usual sites.7 13 Treatment protocol, however, remains the same as for GCT of bone at the more common sites. Recurrence rates in the hand area have been reported to be as high as 20%–90% in some series.3 13 Several authors have reported success in recurrent cases with management using intralesional curettage with adjuvants, excision and reconstruction or ray amputation.3 14 In the present case, tumour resection and bone grafting were performed because adequate extended curettage could not be accomplished in such a small site. Regular follow-ups were scheduled. No signs of recurrence were detected at the first year follow-up. Due to the high rate of recurrence, regular close follow-up should be conducted. Systemic control can also be beneficial in both unresectable and metastatic cases. Monthly denosumab administration has shown promising results, with significant improvement in both gross and histopathological evaluations.15 16 Although intravenous bisphosphonate also reduces both systemic and local recurrences, denosumab was shown to be more effective in a phase III trial, making it the preferred choice.16

Clinical approaches to treating bone and soft tissue tumours should be based on clinical presentation, epidemiology and imaging as well as histopathology to obtain an accurate diagnosis before deciding on a course of treatment. However, as a practical matter, in many cases suspect benign lesions are not able to receive a complete investigation due to limited available resources. That makes this a most challenging situation, especially for a general orthopaedist who may lack experience in interpreting rare events such as this. This case report is an example of appropriate initial management. Symptoms duration, patient age and radiographic findings are important initial clues that can help narrow down the differential diagnosis. In this case, at the first visit a radiographic study showed a confined geographic osteolytic lesion in the shaft of the middle phalanx of the left middle finger without articular involvement. In combination with the insidious clinical symptoms, the radiological findings were most compatible with enchondroma, the most common benign tumour of the phalanges.17 However, other rare bone tumours, including acrometastasis of carcinoma, must be considered as a differential diagnosis. Therefore, a shorter follow-up period of 2–6 weeks after the initial presentation is strongly recommended for general orthopaedists facing a suspected ‘benign bone lesion’. Non-progression of the lesion at follow-up can indicate a slow progressing pathology. Aggressive behaviour of a benign lesion or other malignant lesion would be illustrated by progression in the radiographic study. A delay in progression detection of 1–2 months could change the entire direction of management. Action to detect metastatic lesions during the initial examination should be considered in patients older than 45 years due to the high prevalence of metastasis bone lesion in that age group.18 In such cases, complete physical examination and simple laboratory investigations should be standard procedure.

Short term follow-up with plain radiographic study and MRI is recommended for non-tissue diagnosis of benign-like bony lesions. However, tissue diagnosis should be performed if there are any suspicious clinical progression or imaging studies.