# Bizarre Parosteal Osteochondromatous Proliferation (BPOP) of the Hand

## TL;DR

A rare benign hand tumor called BPOP is described, emphasizing its unique imaging features to avoid misdiagnosis.

## Contribution

A new clinical case of BPOP is presented, highlighting its diagnostic imaging characteristics.

## Key findings

- BPOP appeared as a slowly enlarging finger nodule over five years.
- Imaging showed a parosteal lesion without trabecular bone continuity, typical of BPOP.
- Histological confirmation confirmed the diagnosis of BPOP.

## Abstract

Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora lesion, is a rare benign condition that can mimic other pathologies. A case is described of a 66-year-old man with a slowly enlarging nodule on his finger over five years. Imaging showed a parosteal lesion without continuity with the trabecular bone, strongly suggestive of BPOP. The diagnosis was histologically confirmed. This case highlights the importance of recognizing the characteristic imaging features of BPOP.

Teaching point: BPOP may appear as a worrisome lesion on imaging, but its typical location and lack of continuity with the trabecular bone should raise awareness for BPOP.