# Hypertrophic Osteopathy Concurrent with an Aberrant Right Subclavian Artery in a Dog

## TL;DR

A dog with bone swelling and a rare blood vessel anomaly showed improvement with pain medication but no surgery.

## Contribution

This is the first reported case of hypertrophic osteopathy concurrent with an aberrant right subclanian artery in dogs.

## Key findings

- Computed tomographic angiography identified an aberrant right subclavian artery as a potential cause of hypertrophic osteopathy.
- Palliative treatment with NSAIDs improved intermittent lameness but did not significantly alter hypertrophic osteopathy progression.
- No neoplastic or intrathoracic lesions were found, and gastrointestinal symptoms were absent despite esophageal compression.

## Abstract

Hypertrophic osteopathy (HO) is a rare bone disease characterized by abnormal new bone formation and soft-tissue swelling in the limbs. In veterinary medicine, HO is mainly linked to different underlying disorders, and its development mechanisms are unclear. In this case, report, the only remarkable finding was an aberrant right subclavian artery (ARSA), which is a rare form of vascular ring anomaly in dogs, identified by computed tomographic angiography. This anomalous vessel induced mild dilation of the esophagus above it. Although ARSAs may be a possible cause of HO, the owner declined surgical correction because of potential complications after surgery. After palliative treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief, intermittent lameness improved; however, no significant changes were observed in HO during the follow-up period.

A 13-year-old spayed female cocker spaniel was presented with a 2-month history of swelling in several digits and intermittent hindlimb lameness. Radiographs revealed marked soft-tissue swelling and periosteal new bone formation without cortical bone destruction, characteristic of hypertrophic osteopathy (HO), in the distal parts of all extremities except for the right forelimb. However, no notable findings were detected in thoracic radiographs. An ultrasonography indicated cranial bladder wall thickening, which resolved following antibiotic therapy. Computed tomographic angiography identified a potential underlying cause as an aberrant right subclavian artery (ARSA) originating from the aortic arch, compressing the esophagus and causing mild esophageal cranial dilation to the aberrant vessel. No other intrathoracic or neoplastic lesions were observed. Gastrointestinal symptoms, such as regurgitation, were absent. Although an ARSA was likely the cause of HO, surgical correction was declined by the owner. To the best of our knowledge, this is the first reported case of HO concurrent with ARSA in dogs.