Today’s case is a 6-year-old male neutered Labrador Retriever. Split nail for 4 months on right thoracic limb. Recently developed skin nodule on digit. What are your differentials?
Findings
There is multifocal lysis of the third phalanx of the second digit of the right thoracic limb. Soft tissue swelling surrounds this region and the nail is absent. The remainder of the metacarpal bones and phalanges are normal.
Differential Diagnosis
Aggressive osseous lesion of the third phalanx of the second digit.
- neoplasia (squamous cell carcinoma, melanoma)
- osteomyelitis
Diagnosis
Subungual melanoma
Discussion
Bone lysis of the digit is more commonly caused by malignant neoplasia (83%) than osteomyelitis (17%). Dogs with squamous cell carcinoma had bone lysis (80%) more often than dogs with melanoma (5%).
References
- Marino DJ, Matthiesen DT, Stefanacci JD, Moroff SD. Evaluation of dogs with digit masses: 117 cases (1981-1991). J Am Vet Med Assoc. 1995 Sep 15;207(6):726–8.