Vet Diagnosis: Liposarcoma
Outcome: Tumor was surgically removed
"The intact microchip was found completely embedded within the mass . . . [and] a diagnosis of low-grade liposarcoma was made." (p.188)
Prior to the surgery, the dog had shown no visible signs of cancer other than the unusual lump. Blood tests run on the dog, including a complete pre-operative blood count and serum biochemistry analysis, did not detect that the mass was malignant. Thoracic radiographs (chest X-rays) were also normal. Had there not been a microscopic evaluation of the unusual growth, the cancer might not have been
"Veterinary surgeons are . . . encouraged to check the microchips that have been implanted in pets at least annually, such as when they come in for vaccinations, and report any adverse reaction." (p. 190)
In April 2000, a male mixed-breed dog was implanted with a microchip for identification purposes. In November 2001 (19 months later) the dog's owner detected a firm, painless lump at the implant site measuring 10 x 6 cm (approximately 4 x 2.5 inches). The lump was examined by a veterinarian who determined that the microchip was completely embedded within the mass.
In April 2003, the tumor was surgically removed under general anesthesia. Upon microscopic examination, it was identified as a malignant liposarcoma, an aggressive and invasive type of cancer that can metastasize to the lungs, liver, and bone. The researchers note that liposarcoma is uncommon in dogs.
Vascellari et al., 2004. "Liposarcoma at the site of an implanted microchip in a dog." The Veterinary Journal. 2004;168:188—190.