# A Case Report of Hydatid Cyst Mimicking Thyroid Mass With Mediastinal Extension and Bony Erosion: A Successful Non-surgical Approach to Treatment

## TL;DR

A rare case of hydatid disease mimicking a thyroid mass was successfully treated with medication instead of surgery.

## Contribution

Demonstrates the successful non-surgical treatment of a complex hydatid cyst case with medical therapy.

## Key findings

- Hydatid disease can present as a thyroid-like mass with mediastinal extension and bony erosion.
- Medical management with anthelmintic therapy can be effective when surgery is not feasible.
- Positive Echinococcus serology confirmed the diagnosis after imaging and histopathology.

## Abstract

We report an unusual manifestation of hydatid disease, presenting as a progressively enlarging, painless swelling in the right infraclavicular region. Imaging studies revealed a large necrotic mass extending into the superior mediastinum with the destruction of the adjacent right sternoclavicular joint; this was initially suspected to be thyroidal in origin. However, histopathological examination was consistent with a ruptured hydatid cyst, and Echinococcus serology was positive. Due to anatomical considerations, surgical intervention was not pursued, and the patient was managed with oral anthelmintic therapy, resulting in partial radiological response after 12 weeks of therapy. This case underscores the importance of considering hydatid disease as a differential diagnosis, even with atypical anatomical involvement. It also highlights the potential role of medical management alone as a viable alternative when surgery is not feasible.