Unusual distal tibia BCOR sarcoma: A case report and review of imaging features

Puja Bharucha

doi:10.33118/oaj.rep.2019.01.008

Abstract

Ewing’s sarcoma is a common pediatric sarcoma. There is a subset of tumors similar to Ewing’s sarcoma in several aspects, but negative for all known translocations. The BCOR sarcoma is one example. There are limited descriptions of the radiologic imaging findings. Previous reports describe the radiologic features as “aggressive” and “similar” to Ewing’s sarcoma. This implies a permeative lesion centered in the diaphysis. Our case was geographic with a well-defined border and sharp zone of transition. Keywords: Ewing’s sarcoma, BCOR sarcoma, Imaging.

Highlights

Ewing’s sarcoma is one of the most common primary round cell sarcomas in the pediatric population
The BCOR sarcoma is similar to Ewing’s sarcoma in several clinical and morphological aspects. These include a predilection for long bones in a pediatric and young adult population with a shift towards a slightly older patient population relative to Ewing’s sarcoma [1, 8]
The majority of BCOR sarcomas that have been reported to date are bone-based tumors; there have been many cases of discrete soft tissue based tumor [1, 6, 7, 9, 10]

Summary

Introduction

Ewing’s sarcoma is one of the most common primary round cell sarcomas in the pediatric population. A - High power image from initial biopsy (hematoxylin and eosin stain, 40x) shows a highly cellular tumor composed of round to ovoid blue cells with marked size variation, atypical mitotic figures, and no distinct architectural pattern, arranged in a loose collagenous stroma. Subsequent pathological evaluation of the below the knee amputation specimen of the right lower extremity (Fig. 5) demonstrated that the tumor measured 6.5 x 3.4 x 2.7 cm and was centered in the metaphysis of the distal tibia extending to the distal diaphysis, epiphysis, medullary cavity, and regional soft tissues between the distal tibia and fibula.

Results

Conclusion