Mammoth Giant Cell Tumor of the First Metacarpal: A Case Report and Management Trends

Giant cell tumor (GCT) is classically described as a locally aggressive, epiphyseo-metaphyseal osteolytic tumor occurring in young adults. They are mostly seen in long bones while some are also found in the iliac bone and spine and a very small proportion occurs in hand bones. Due to the rarity of GCT in metacarpal, there is a paucity of treatment options available. In an extensive literature search on PubMed, Embase, Medline, and Ovid from 2004 till date, very few cases were reported. The various treatment options available are intralesional curettage with or without adjuvant therapy, wide resection, free osteoarticular metatarsal transfer, and, occasionally, ray amputation may also be done. After simple curettage, a reasonably high recurrence rate also imposes comprehensive en-bloc excision, but still, there are many case reports of recurrence. Experience with a case of GCT of the whole first metacarpal extending from the carpometacarpal to the metacarpophalangeal joint is not thoroughly described in the literature. We hereby report a mammoth GCT of the first metacarpal treated by excision and reconstruction by free fibular graft and adjacent joint fusion with an excellent functional outcome at one-year follow-up.


Introduction
Giant cell tumor (GCT) is described as a locally aggressive, osteolytic tumor occurring in young adults at the epiphyseal region. Around 80%-90% of giant cell tumors are seen in long bones, 4% in the iliac spine and iliac bone, and only 2% of giant cell tumors are described in hand. (the phalanges, rarely, are located within the thumb and metacarpals). Unni reports an incidence of 1.7% for giant cell tumors of metacarpals [1]. According to Averill et al., less than 1.5% of giant cell tumors are reported in metacarpal [2]. Due to the rarity of GCT in metacarpal, there is a paucity of treatment options available. In an extensive literature search from 2004 till date, only 22 cases were reported.
The various treatment options available are intralesional curettage with or without adjuvant therapy, wide resection of the tumor, followed by joint reconstruction by allograft or arthroplasty, joint arthrodesis augmented with bone graft, free osteoarticular metatarsal transfer, and, occasionally, ray amputation. Initially, after curettage followed by autologous bone graft, around 90% of recurrence was reported [3], leading to extensive en block excision of the tumor as the only option [4]. We hereby report our experience with a case of GCT of the whole first metacarpal extending from carpometacarpal to metacarpophalangeal joint and discussing all possible treatment options available for metacarpal GCT.
Most of the GCT of the first metacarpal is small and retractable. We are reporting a case of mammoth GCT of the first metacarpal, which was treated by excision and reconstruction by free fibular graft and adjacent joint fusion.

Case Presentation
A 29-year-old female came to the orthopedic outpatients' department (OPD) with a complaint of swelling of her left thumb with global restriction of thumb movement. The swelling was gradually progressive and associated with pain. There was no history of any constitutional symptoms or any injury. Initially, the patient had taken an indigenous system of treatment in the form of local ointment and heat application and developed a skin reaction; thereafter, the patient came to the orthopedics department. The patient had undergone a core needle biopsy with the diagnosis of GCT on histopathology. On physical examination, there was localized swelling over the right first metacarpal, of size around 10 x 7 x 4.5 cm, with variable consistency. The overlying skin was scarred with adhesion on the needle biopsy site, and the movements of the metacarpophalangeal (MCP) and trapeziometacarpal joints were painful and restricted. Roentgenogram revealed an expansile osteolytic lesion of the first metacarpal in totality with a pathological fracture ( Figure 1, panel d). A magnetic resonance scan (Figure 1, panel c) showed a 7.6 x 6.6 x 4.2 cm mass, which involved the whole first metacarpal in totality. The swelling was adherent to the skin and lesion on the biopsy site near the MCP joint. It was decided to excise the involved metacarpal in totality and reconstruct the thumb by a free fibula graft and adjacent joint fusion. A dorsal longitudinal incision was given, extending from the first carpal metacarpal joint to the first proximal phalanx, crossing over the center of swelling. The skin and tendons over the swelling were retracted and extension tendons were cleared by a sharp knife and thermocautery. En-block resection of the tumor was done. The same length of the diaphyseal fibula was excised from the middle one-third of the left leg. To promote the union process, the articular surface of the trapezium was shoveled to expose good cancellous bone for fusion. A free fibular graft of size of the first metacarpal was fixed between proximal phalanx and trapezium in 40-degree abduction and flexion with the help of 2.6 mm transarticular Kirschner wire to achieve arthrodesis of the trapezium and proximal phalanx with fibula graft (Figure 2) in the functional position. The fibula graft was covered by the surrounding interosseous muscles and the incision site was closed in layers. A unilateral thumb spica slab was given postoperatively and was replaced by a spica cast after suture removal on the 14th day after surgery.

IITV: image intensifying television
Postoperatively, the excised specimen was confirmed as GCT on histopathological examination. The Kirschner wire, along with a thumb spica cast, was removed three months after the surgery. Thumb and wrist range of motion exercises were then started. Postoperative radiograph at 12 months showed a well-accepted fibula graft fused distally with first proximal phalanx and proximally with trapezium, with not a radiological sign of tumor recurrence and the patient has an optimum functional thumb ( Figure 3).

Discussion
Giant cell tumor accounts for about 4%-5% of all bone tumors and around 20% of benign bone malignancies. Most GCT are locally aggressive, but their course of progression is unpredictable, as many cases of distal metastasis are also reported in the literature [5]. GCT is mainly seen in long bone (around 75%-90% in the distal femur followed by 25% in the upper end of tibia, distal radius, and humerus [1] and only 1.7% to 4% in hand bones [1][2][3].
GCT of the hand are more locally aggressive, so in comparison to other long bone giant cell tumors, the signs and symptoms appear rapidly and expound even in the younger patients.
GCT usually present with clinical features of swelling and pain. It affects typically the epiphysis and epiphysis metaphysis region of the metacarpal. The differentials include aneurysmal bone cyst (ABC), nonossifying fibroma, and osteosarcoma [6][7]. A management protocol of the giant cell tumor in metacarpal has not progressed very much in the past few decades, due to the less availability of cases in the literature. Versatile modalities available with us are intralesional curettage with or without adjuvant therapy, wide resection, joint reconstruction techniques, including total joint replacement, allograft reconstruction, joint arthrodesis augmented with bone graft, free osteoarticular metatarsal transfer, and, occasionally, ray amputation.
We reviewed 23 (27 patients  In 2012, Jin Chang Moon et al. reported a rare case of second metacarpal GCT in a 54-year-old patient, which was managed with chemotherapy with excellent results [17]. In the same year, Keith Jackson et al. reported one case of recurrence of fourth metacarpal GCT after 43 years of initial treatment, representing the versatility of GCT [18].
After curettage followed by autologous bone graft, around 90% of recurrence was reported [3], leading to extensive en-block excision of the tumor as the only option [4]. Procedures like local resection or ray amputation are used to eradicate the disease but long-term follow-up results are still not available in the literature.
Maini et al. tried to preserve the joint function of the fifth metacarpal giant cell tumor; they did en-bloc resection of the tumor with the fifth metacarpal and regained joint function with free osteoarticular metatarsal with the joint capsule, synovium, and ligaments transfer in a single-stage surgery. They hypothesized that the synovial layer of the proximal phalanx provides continuous nutrition to cartilage and metatarsal head, which enhances graft uptake [19].
Patrick S et al. used an autologous tricortical iliac graft after ray amputation of metacarpal giant cell tumor [14]; similarly, Manfrini et al. managed recurrent giant cell tumor by en-block resection and autologous fibula graft with implant arthroplasty at the metacarpophalangeal joint and observed excellent hand function in eight-year follow-up [9]. We reported a rare case of entire first metacarpal GCT in an around 29year-old female, which was managed with en-block resection of the tumor with interposition of free fibular bone graft and MCP and carpometacarpal joint arthrodesis. This option allowed salvage of the patient's native thumb with functional use as a stable post, to which she can pinch and grasp objects.
In contrast to implants, heavy plates, and screws interfering with tendon gliding, we could achieve adjacent metacarpophalangeal and carpometacarpal joint fusion with the help of only K wire and supplemented plaster support. We are reporting the case for its size (mammoth), total excision of the thumb metacarpal, fibula graft reconstruction, transarticular K wire arthrodesis, and its rarity.

Conclusions
Giant cell tumor of the metacarpal is a rare type, with rapid progression of signs and symptoms even in young patients. They are osteolytic locally aggressive tumors with a high incidence of metastasis and recurrence. En-bloc resections of tumors with a 1 cm safe margin prevent recurrence in most cases. But the loss of hand function cannot be exigent. We proposed single-stage surgical resection of the first metacarpal and reconstruction by free fibular graft reconstruction. The short-term result is very encouraging with respect to both the function and absence of recurrence and are awaiting long-term follow-up.

Additional Information Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.