# Atypical Early Presentation of Multicentric Carpotarsal Osteolysis: Ankle Pain and Cavovarus Deformity Without Osteolysis

## TL;DR

A rare bone disorder called MCTO presented with ankle pain and foot deformity in a child, diagnosed through genetic testing despite lack of typical bone loss.

## Contribution

Highlights an atypical early presentation of MCTO without visible bone loss, emphasizing the importance of genetic testing for accurate diagnosis.

## Key findings

- A 9-year-old female presented with ankle pain and cavovarus deformity but no visible osteolysis.
- Genetic testing confirmed a pathogenic MAFB variant, diagnosing MCTO despite atypical imaging findings.
- Early recognition of subtle symptoms can prevent misdiagnosis and unnecessary interventions.

## Abstract

Multicentric carpotarsal osteolysis (MCTO) is a rare skeletal dysplasia classically associated with carpal and tarsal osteolysis. Its presentation is highly variable, ranging from subtle musculoskeletal deformities to progressive bone loss and renal involvement. We report a nine-year-old female who presented with progressive ankle pain, cavovarus foot deformity, and gait disturbance. Initial radiographs demonstrated osteopenia and bilateral pes cavus without frank osteolysis. Genetic testing identified a pathogenic MAFB variant, confirming the diagnosis of MCTO.

This case highlights the broad clinical and radiologic spectrum of MCTO, in which early or atypical presentations may have subtle, nondiagnostic imaging findings. Recognizing these early features can raise clinical suspicion and prompt genetic evaluation, helping to avoid misdiagnosis and unnecessary interventions. Awareness of the broad spectrum of clinical and radiographic findings is essential for timely diagnosis and appropriate management.