Chondroblastoma-like osteosarcomas are extremely rare malignancies having varying clinical, radiological and histological features. Their rarity causes challenges in both diagnosis and clinical management. They are often misdiagnosed as benign lesions. Their accurate diagnosis is important because they require adequate treatment. Misdiagnosed lesions or undertreatment may result in recurrences. We report a case of chondroblastoma-like osteosarcoma arising in the left first metatarsal bone with tarsometatarsal joint involvement in a 10-year-old boy for whom surgery with an original technique was planned after a multidisciplinary diagnostic review.