Giant cell tumor (GCT) is an osteolytic benign aggressive tumor that presents with bone destruction soft-tissue impingements and has malignant potential, and rarely metastasizes to pulmonary tissues (<2%) [1, 2]. Sir Astley Cooper first described it in 1818. GCT most commonly occurs in young adults (20–30 years), approximately 4–9.5% of all primary osseous tumors and 18–23% of benign bone tumors [3, 4]. It occurs most commonly at epiphyses-metaphysis of long bones 85–90% such as the distal femur, proximal tibia, distal radius, and proximal humerus, does occur in the spine, and pelvis 4–5% and rarely in small bones such as hands and feet 1–2% ^[4]. Radiologically, a large eccentric geographic osteolytic with no matrix mineralization and a thinned-out cortical lesion, Cam Panacci grade (1–3) ^[5] and LodWick type 1b/1c [5-8] commonly called a soap bubble appearance is seen. On histopathology, multiple giant cell lesions based on the aggressivity of the tumor presentation are seen ^[9]. GCT in small bones rarely occurs it needs to be managed meticulously and aggressively as it has a high malignant potential and recurrence with 0–65%. Hence, it has been classified as stage 3 of Enneking’s benign bone tumors [5, 10]. Hence, these tumors should be managed with diagnostic fine needle aspiration cytology (FNAC) or TruCut biopsy and definite surgical intervention with extended curettage/high-speed burring, adjuvant Argon beam photocoagulation, intra-lesional hydrogen peroxide (H₂O₂) chemoablation plus auto/allogenous graft [11,12]. We have encountered one such rare case presentation of GCT 1^st metatarsal and managed with a unique reconstruction with autogenous fibular cortical strut graft.

A 23-year-old female presented with complaints of swelling over the dorsum of her left foot for the duration of 2 years and pain in that foot for 1 year. The swelling was insidious in onset and progressive. Pain was mild, dull, aching, intermittent type, aggravated on activities of daily living such as squatting, standing, walking, climbing stairs, and running, and relieved on taking analgesics and rest. No history of swelling elsewhere, no constitutional symptoms, and no members of the family both paternal and maternal had similar complaints. On examination, there was a localized ovoid swelling 8 × 5 cm over the dorsum of the left foot, over 1^st metatarsal area with well-defined margins, tender on deep palpation, firm in consistency, overlying skin was free, with shortening of 1^st ray, with no sinus, discharge, and discoloration (Fig. 1).

Radiographs revealed a large geographic expansile eccentric osteolytic lesion in the 1^st metatarsal. The classical “soap bubble appearance” is seen. Stage 3 Enneking, Cam Panacci Grade 2 and LodWick 1c. A chest X-ray anteroposterior view showed normal and was negative for parenchymal lung lesions (Fig. 2). Before planning for a biopsy, an FNAC was sent and was diagnosed as a giant cell lesion. Routine blood investigations include complete hemogram, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), liver and renal function tests were within normal limits and negative serology, with the patient and her attendant’s written consent taken for proposed surgical management.

Surgical procedure

An incision was taken over the dorsomedial approach on the left foot, extending from the head of the 1^st metatarsal to the navicular. The tumor site is exposed and the excision of the tumor with a distally preserved cuff of 1^st metatarsal articular cartilage (Fig. 3).

Intra-lesional H₂O₂ chemoablation was done to remove all the nidus sites and the 1^st metatarsal length measured from the contralateral foot and an ipsilateral fibular strut graft of 1 cm more than the measured length of the contralateral 1^st metatarsal is taken and inserted into the troughs created in medial cuneiform and preserved 1^st metatarsal distal articular cartilage and the specimen was sent for histopathological examination and inspected both proximally and distally (Fig. 4). 1^st metatarsal length was measured from the contralateral foot, and an ipsilateral fibular avascular stud graft of 1 cm more than the measured length of 1^st metatarsal was taken and inserted into the troughs created in medial cuneiform and preserved (Fig. 5).

1^st metatarsal normal articular cartilage and bone, fixed with intramedullary K-Wire and 10-hole re-construction plate with cortical screws from distal to proximal through normal viable 1^st metatarsal bone and cartilage to medial cuneiform extended till navicular (Fig. 6).

Histopathological examination

The report showed to be a multiple multinucleated benign giant cell lesion on both 10 and 40x (Fig. 7).

Follow-up protocol

Post-surgery, she was kept in below knee slab for 6 weeks and advised non-weight bearing. K-wire was removed after 6 weeks. She’s advised to mobilize after 6 weeks with touch-toe (partially weight bearing) and complete weight bearing after 3 months. At 12 weeks, we noticed graft union radiologically. At 1 year follow-up, she’s actively mobilizing and doing all the activities of daily living without hindrance with no signs of discharge/sinus (Fig. 8). Radiographs after 1 year showed good graft integration with no signs of recurrence (Fig. 9).

Giant cell tumor (GCT) are usually solitary lesions, but 1–2% can be synchronously or meta-synchronously multicentric [2, 13]. GCT in the small bones (i.e., metacarpals, metatarsals, phalanges) are very rare and are more malignant than other regions; hence, a thorough clinical history and examination of the hand and foot should be evaluated to rule out differential diagnoses such as an aneurysmal bone cyst, angiosarcoma, enchondromas, osteosarcoma, giant cell reparative granuloma, non-ossifying fibroma, brown tumor/hyperparathyroidism, metastatic tumor, and infective including acute/chronic osteomyelitis, and tubercular osteomyelitis [12,14- 17]. Investigations include radiographs of affected extremities/regions, complete blood examination including CRP and ESR, and histopathological examinations (i.e., FNAC and Biopsy [incisional and excisional]) [11,12,15,16,18] to know the etiology and its pathogenesis. GCT consists of 3 cell types: Neoplastic GCT stromal cells, represented as the proliferative population, mononuclear histiocytic cells recruited to the area, and multinucleated giant cells ^[9]. Genetic analysis of GCT of bone would reveal several cytogenetic abnormalities resulting from nonrandom translocations involving breakage and fusion of chromosome telomeres known as “telomeric associations” [14, 19]. The bone erosive tendencies of GCT of bone have been associated with the ability of tumor cells to express multiple cytokines. Stromal cells from excised GCT lesions in bone patients have demonstrated the production of vascular endothelial growth factor, a matrix metalloproteinase-9. Moreover, higher mRNA up-regulation (as detected by reverse transcriptase polymerase chain reaction) is evident in advanced-stage GCTs (stage II/III). This observation is also linked to increased bone destruction and the likelihood of local recurrence ^[20]. Aggressive treatment and meticulous excision are essential for managing GCT in the hand and foot ^[21]. Benign aggressive tumors like GCT in small bones demand careful management and thorough follow-up to monitor recurrence. Magnetic resonance imaging (MRI) of the foot can be utilized, if necessary, to detect soft tissue spillage, which could serve as a potential nidus for tumor recurrence. Over the years, management of GCTs of the metatarsal (area of interest) and small bones (Table 1).

To the best of our knowledge and information available in the various search standard databases gathered the area of interest studies from the past 10 years [11, 12, 15-18, 22-25], we noticed a unique way of reconstruction could be done, and all the above-mentioned techniques and procedures showed less signs of recurrence with good stability and better functional outcomes.

Limitation of our study

It needs long-term follow-up because the recurrence of small bone GCT does occur at 2–3 years ^[14]. MRI was not taken hence missing out on the soft-tissue involvement for the nidus or site of GCT other than 1^st metatarsal [11, 12, 20].

Benign aggressive bone tumors are managed with complete excision and reconstruction with autografts/allografts/bone cement for functional outcome and to prevent a recurrence. Our management showed the viability of the graft radiologically after 1 year with no recurrence and excellent functional foot outcome.

Benign aggressive bone tumors include GCTs and aneurysmal bone cysts. GCT in small bones has high rates of malignant potential that should be addressed with thorough pre-operative evaluation and planned surgical excision with either chemoablation or radio-ablation to kill all the tumor cells in the surrounding tissues, and carefully monitor the patient with repeated interval follow-ups, also fibula graft reconstruction is encouraged to provide structural stability and cosmetically acceptable.