Infantile desmoid-type fibromatosis in an Akita puppy

Mammary fibromatosis in a female dog: case report

Fibromatosis, or desmoid tumour, is characterized by excessive and infiltrative proliferation of connective tissue originating from aponeurotic muscle structures. Mammary fibromatosis is rare in humans and animals and its precise aetiology is unknown. A 10-year-old mixed-breed female dog developed a mass in the right cranial thoracic mammary gland (M1) and underwent lumpectomy. The mass was firm, with an irregular surface and distinct limits. Microscopically, it was a neoplastic proliferation of fusiform cells with low atypia, interspersed with abundant dense collagenous tissue, confirmed by histochemical staining with Gomori's trichrome and Masson's trichrome and immunopositivity for vimentin and smooth muscle actin, confirming mammary fibromatosis. Mammary fibromatosis in dogs needs further studies to elucidate its clinical, epidemiological and aetiopathogenic aspects.

Abdominal wall mass and hemoabdomen in a Haflinger mare

A 6-year-old Haflinger mare was presented with a history of recurrent hemoabdomen. On necropsy, a firm infiltrative multinodular yellow mass was observed in the wall of the posterior abdomen. Histopathologic examination revealed a proliferation of fibroblastic cells, which were positive for α-smooth muscle actin and vimentin.

Diagnostic features of feline restrictive orbital myofibroblastic sarcoma

A progressive debilitating disease of the orbit and adjacent connective tissues of cats has historically been called feline orbital pseudotumor. The authors reviewed clinical, histopathologic, and diagnostic imaging features of this disease in 12 cases from the Comparative Ocular Pathology Laboratory of Wisconsin. The cats' ages ranged from 7 to 16 years (mean, 10.8 years). All cats had a history of severely restricted mobility of the globe and eyelids with secondary corneal disease. Eleven cats (92%) had concurrent involvement of the contralateral eye and/or the oral cavity. Diffuse scleral or episcleral thickening was seen with computed tomography in all clinically affected eyes. Histologically, an insidious infiltration of neoplastic spindle cells in the orbit, eyelids, and periorbital skin and soft tissues, with collagen deposition and a few perivascular lymphocytes, led to entrapment and restricted mobility of the eyelids and orbital tissues. The tumor failed to form a discrete mass, and it spread along fascial planes to the contralateral orbit and eyelids and/or the lips and oral cavity. In all tested cases (n = 10), neoplastic cells were immunohistochemically positive for vimentin, S100 protein, and smooth muscle actin. The authors adopted the term feline restrictive orbital myofibroblastic sarcoma to reflect the restricted mobility of the eyelids and globe and the imaging and histologic features of an invasive yet low-grade myofibroblastic sarcoma.

Fibromatosis in a Young Bernese Mountain Dog: Clinical, Imaging, and Histopathological Findings

A young, intact, male Bernese Mountain Dog was presented to the animal hospital for lameness and diffuse thickening of the soft tissue in the right hind limb. Magnetic resonance imaging revealed multiple, multilobular, space-occupying lesions within and between the muscles of the right femur. Biopsies taken from the lesions revealed an infiltrative mass composed mainly of collagen fibers and a low density of benign-appearing fibroblasts. These findings were compatible with a diagnosis of a fibromatosis. Taking the age of onset into account, infantile fibromatosis was most likely. A deep fibromatosis, similar to that seen in adults, could not be excluded based on histology.