Primary cervical aggressive fibromatosis with spinal cord compression in a cat

Desmoid tumors, also known as aggressive fibromatosis, are benign neoplastic proliferations with a high capacity for invasion into adjacent tissues and are incapable of promoting metastasis. Despite being rare, it is well described in medicine, whereas only isolated reports exist in veterinary medicine. Herein, we describe a case of primary aggressive fibromatosis affecting the cervical region of a young cat and associated with spinal cord compression and neurological signs. Magnetic resonance imaging revealed spinal cord compression and hypointensity on pulse sequences, which guided localization and facilitated excisional biopsy of the lesion. Histopathological examination suggested aggressive fibromatosis due to the benign proliferation of well-differentiated spindle-shaped mesenchymal cells with an abundant collagen matrix and invasion into the adjacent muscle tissue. After the surgical procedure and spinal cord decompression, the neurological symptoms improved. To date, no clinical signs of recurrence have been observed in this patient. The objective of this report was to describe a case of aggressive fibromatosis associated with neurological signs in a domestic cat, with an emphasis on clinical and diagnostic aspects, as this disease is rare and there is limited information in the veterinary literature regarding it.