# Osteochondroma-like parosteal osteosarcoma: A case highlighting diagnostic challenge and surgical advances

## TL;DR

A rare bone tumor case shows how difficult diagnosis can be and highlights new surgical techniques using 3D printing.

## Contribution

Presents a rare osteochondroma-like parosteal osteosarcoma case and demonstrates the use of 3D printing in its surgical treatment.

## Key findings

- Needle biopsy misdiagnosed the tumor as cartilaginous, highlighting diagnostic challenges.
- Multidisciplinary discussions were crucial for accurate diagnosis and treatment planning.
- 3D printing technology was used to improve patient-specific surgical techniques.

## Abstract

Parosteal osteosarcomas are uncommon malignant bone tumors that arise from the bone surface. Their heterogenous components can present challenges in diagnosis. We present a case of a rare variant of this tumor known as an osteochondroma-like parosteal osteosarcoma, which was initially misdiagnosed as a cartilaginous tumor on core needle biopsy. Surgical resection of the tumor ultimately allowed for definitive diagnosis. Our case demonstrates the limitations of needle biopsy in diagnosing variants of parosteal osteosarcoma and the vital role of multidisciplinary discussions in guiding diagnosis and treatment. Furthermore, our case utilizes 3-dimensional printing technology in the surgical treatment, and illustrates the recent advances in patient-specific surgical techniques.