A 33-year-old man presented with a slowly progressive swelling in the middle l/3rd of his right tibia. X-rays examination revealed multiple sharply demarcated radiolucent lesions separated by areas of dense and sclerotic bone. Microscopic examination of a biopsy specimen revealed island of epithelial cells in a fibrous stroma. Which of the following is the most probable diagnosis?

Ans- A Adamantinoma Adamantinoma characteristically presents in the tibial diaphysis of a middle aged person with mild to moderate discomfort, islands of epithelial cells in a fibrous stroma (hall mark) histologically, and bubbly bone destruction (radiolucent lesions separated by dense sclerotic bone) radiologically. Adamantinoma Key points Adamantine epithelioma or Lichtenstein dermal inclusion tumor. Almost exclusively found in tibial diaphysis Mild pain & palpable mass over anterior tibial border Islands of epithelial cells Bubble like defect in anterior tibial cortex, sometimes with thickening of surrounding bone Treatment is wide local excision Bone Tumor Most Common Site Unicameral/Solitary/Simple Bone cyst Metaphysis of proximal humerus > femur Aneurysmal Bone cyst Lower Limb Enchondroma Metaphysis of small bones of hands (& feet) Osteochondroma (Exostosis, m.c. benign bone tumor) Distal femur > upper tibia > proximal humerus Osteoid osteoma Femur> tibia (diaphysis) Osteosarcoma Distal femur > Upper tibia (metaphysis) Ewing's sarcoma Femur> Tibia (diaphysis) Fibrous dysplasia Upper end femur (22%) > Tibia (21%) > lower femur (12%) Chordroma Sacrum (most comnmon) > sphenooccipital region (clivus)> anterior vertebral body i.e. involves only axial skeleton Ivory osteoma or compact or Eburnated Osteoma Frontal sinus Adamantinoma Tibia (MC lone bone) Multiple myeloma Vertebrae Age predilection Tumor Age Range years) Ewing's tumor 5-15 Non ossifying fibroma Simple (unicameral) bone cyst 2-20 Aneurysmal bone cyst 5-20 Osteogenic sarcoma 10-20 Osteoclastoma (GCT) 20-40 Multiple myeloma Metastasis > 40