Case Study

CT – Toe mass lesion with metaplastic changes of the horn in a 11 year old FS Schnauzer

This 11 year old FS Schnauzer has a plantar mass on the right hind 4th toe.

DX

The findings are consistent with the history of mass lesion at the fourth toe emerging from the paw pad with metaplastic changes of the horn

Image Interpretation

CT of the distal right limb –

At the plantar aspect of the fourth phalanx a soft tissue attenuating, irregular shaped mass is emerging from the digital pad, the mass measures 1.6 x 1.4 x 2.1cm. The transition between the mass and surrounding tissue is mildly ill defined. The normal hypoattenuating center of the digital pad is lost. The plantar surface of the pad presents multiple marked conically shaped protrusions. The bony architecture of the fourth phalanx is within normal limits. There is no evidence of osteolytic or osteproliferative processes. A smooth bridging osteophyte new bone formation is present onto the dorsal aspect of the second and third tarsal and the central tarsal bones.

Outcome

Possible differentials are adenoma, fibroma, squamous cell carcinoma, fibrosarcoma, other. Even though a benign lesion is considered more likely due to the lack of aggressive changes of the
bone, the biological behavior can only be determined by histopathology.
Amputation of the fourth toe of the right rear limb appears to be the treatment option of
choice. Full tumor staging should be obtained prior to surgery.