An Unusual Case of Giant Cell Tumor of First Metatarsal: A Rare Case Report and Review of Literature.

INTRODUCTION: Giant cell tumor (GCT) or osteoclastoma is an osteolytic, mostly benign but locally aggressive tumor occurring in young adults at the epiphysis. Area of predilection is mainly long bones (85-90%). 4% of GCT are also found in iliac bone, spine and only 2% in hand (of which GCT phalanges are more common than metacarpal). GCT of metatarsal is a very rare occurrence with very few cases being reported so far. We report a case of GCT 1st metatarsal in a 40-year-old male which is a very rare entity. We shall discuss the clinical features, pathological and radiological hallmarks, and the various treatment modalities of such lesion.

CASE REPORT: A 40-year-old male presented with complain of swelling over the dorsum of left foot for the duration of 2 years and pain in that foot for 4 months. Swelling was insidious in onset and has progressively increased in size. Pain was mild to moderate in intensity, dull aching and continuous. On examination, there was a localized ovoid shaped swelling 7 by 4 cm over the dorsum of the left foot opposing 1st and 2nd metatarsal area with well-defined margins, tender on deep palpation, hard in consistency and the overlying skin was free. Radiographs revealed an expansile osteolytic lesion of entire 1st metatarsal involving the articular surface of tarsometatarsal joint and metatarsophalangeal joint with impingement on 1st metatarsal and cortical thinning. The classical "soap bubble appearance" was also present. Fine needle aspiration cytology was done to confirm our diagnosis of GCT. According to Campanacci et al ., the tumor was histologically graded as Grade II tumor. A reconstructive surgery with fusion of the Cuneiform metatarsa and metatarsophalangeal joint was planned. The tumor was carefully removed with a cuff of normal tissue and the proximal and distal joints were inspected. There was no articular cartilage of the Cuneiform metatarsa joint. A fibular graft was taken and was inserted into the troughs created in medial cuineform and proximal phalanx and fixed with K-wire, both proximally and distally. The patient was given a below knee cast for three months postoperatively. Full weight bearing was started after 3 months. After 9 months of follow-up, the graft was well taken up and there were no signs of recurrence both clinically and radiologically.

CONCLUSION: Local resection of the involved metatarsal with autograft or allograft replacement is the preferred surgical treatment for several reasons. First, no correlation has been found between the grade of GCT and the rate of recurrence. Therefore, all giant tumors of foot should be considered locally aggressive. In addition curettage with or without bone grafts has resulted in recurrence rates of about 90%. Thus curettage is an unacceptable form of treatment. Second, although amputation may prevent recurrence, it is cosmetically deforming and decreases the function of the foot.