Lingual Granular Cell tumour in a dog

These are sections taken from a mass in the tongue of 10-year-old male Labrador.

Fig 1. The subepithelial stroma and underlying muscle of the tongue are infiltrated by patternless spindle to polygonal neoplastic cells separated by a fine collagenous stroma.
Fig 2. The neoplastic cells contain moderate amounts of coarsely granular pale eosinophilic cytoplasm, a key feature of this tumour. Nuclei are bland with indistinct nucleoli. Cellular pleomorphism and variation in nuclear size are mild. Mitoses are rare.
Fig 3. The neoplastic cells can be seen infiltrating the muscle bundles.

Final Diagnosis

Granular cell tumour


These tumours tend to be slowly progressive and are believed to be neural in origin. In dogs, the tongue is the most commonly affected site and so this is an important differential diagnosis for a tumour affecting the tongue. Currently, the rate of recurrence following complete excision and the risk of metastasis are believed to be low.