BACKGROUND: 1% of all bone tumors are Chondroblastomas. Chondroblastomas, initially considered to be an osteoclastoma variant are benign, cartilaginous tumors which usually occur in the epiphysis of long bones, especially in the humerus, tibia, and femur, most common in children and young adults between the ages of 10 and 20 years. 4% of all chondroblastomas settle in the talus whereas cuneiform and other tarsal bones are very rare sites for the development of this benign chondroid lesion.

CASE REPORT: A case of chondroblastoma involving the medial cuneiform of the left foot of a 32 year old woman is described. The patient presented with moderate localized pain and tenderness over the medial aspect of her left foot. Radiographs showed a lytic expansile lesion within the right cuneiform bone indicating a bone tumor. Biopsy demonstrated cellular areas made up of round, polygonal cells, with round-oval nucleus and chondroblasts that appear with a thin calcification rim. Intralesional curettage and synthetic bone grafting with PRP (Platelet-Rich Plasma) application was performed for its treatment. After 18 month follow up, osteointegration was observed with the defect completely filled and the patient was free of disease and pain.

CONCLUSIONS: A painful, expansile, thin, sclerotic lesion detected at the cuneiform should arise suspicion for chondroblastoma even at age over 20 years. Meticulous curettage of the lesion from a small window with removal of the lesion followed by injectable phosphocalcic cement application with autologous PRP can be considered as a curative and technically simple treatment method.

Keywords: Bone Neoplasms - diagnosis, Biopsy, Chondroblastoma - diagnosis, Diagnosis, Differential, Tarsal Bones