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.

Intramuscular desmoid tumor (musculoaponeurotic fibromatosis) in two horses

Intramuscular desmoid tumors (musculoaponeurotic fibromatosis) were discovered in two young adult horses. The tumor in one horse was in the lateral cervical musculature, and that in the second horse occurred in the pectoral musculature. Histopathologic features were similar in both horses and included proliferation of fibroblasts and cells expressing muscle actin (myofibroblasts), with extensive dissecting fibrosis within muscle. These features are similar to those of desmoid tumors in humans, particularly those also known as musculoaponeurotic fibromatosis. Dissection of these lesions revealed a single central (horse No. 1) or multiple central (horse No. 2) fluid-filled cavities with associated sterile inflammation. The presence of these cavities supports the hypothesis that equine desmoid tumors are traumatic in origin, possibly occurring at sites of injections or bursal rupture. Surgical excision of the tumor in horse No. 1 was apparently curative, but the extent of the tumor in horse No. 2 precluded surgical excision.

Infantile desmoid-type fibromatosis in an Akita puppy

A 10-week-old Akita puppy was evaluated for a reported umbilical hernia. Repair of the hernia had been attempted three times prior to referral. A defect in the ventral abdominal wall with an associated soft-tissue mass was identified on abdominal radiographs. Exploratory surgery was performed; the mass was resected and the abdominal wall defect was repaired. Histopathological evaluation of the mass was consistent with infantile desmoid-type fibromatosis.

[First description of a desmoid tumor in a goat and comparative observations to human fibromatosis. Case report]

The macroscopical, histological, and ultrastructural aspects of the abdominal and extra-abdominal desmoid tumour are reported in a 1 1/2-year old goat (breed: Nera-Verzasca, Tessin mountain goat). Macroscopically, the disease was characterized by glassy, whitish, very hard, plate-forming masses found in the abdominal wall and in the medial aspect of the upper hind limbs. Histologically, the masses consisted of well differentiated fibroblasts which locally infiltrated the surrounding tissues. No capsule formation was found. On electron microscopy, the cells appeared to be active, young, collagen-producing fibroblasts. The pathogenesis of this disease is unknown.