Diagnosis and Surgical Treatment Methods for Mammary Gland Carcinoma and Fibrosarcoma in Dogs
Mammary gland carcinoma and fibrosarcoma are two neoplastic diseases in dogs. Diagnosis is mainly based on histopathological changes, and treatment mainly relies on surgical excision.
1 Clinical symptoms
In September 2001, a Chow Chow dog owned by Li in Dongli District of Harbin City was brought in for examination. The affected dog was an 11-year-old female that had never given birth. Half a month earlier, a hard nodule had appeared in the left rear mammary gland, with irregular edges; a small amount of white fluid sometimes flowed from the nipple. Later the nipple became swollen, the mammary gland was itchy, and the affected dog frequently licked and bit at it. Two days before the examination, many hard nodules of varying sizes appeared in a band-like pattern on the skin extending from the affected mammary gland toward the left anterior scapula. The affected dog was emaciated, had a normal appetite, and preferred to lie down. On clinical examination, the body temperature was 39.3°C, the pulse was 78 beats/min, and the respiratory rate was 16 breaths/min.
2 Histopathological changes
2.1 Mammary gland induration
Diffuse infiltration of cancer cells was visible, with some forming tubular structures. The cancer cells were pleomorphic large cells, with oddly shaped nuclei, obvious mitotic figures, deeply stained nuclei, and cytoplasm that also stained darker than that of somatic cells, with most containing vacuoles. There was abundant collagenous stroma, and infiltration of neutrophils and lymphocytes was visible within the stroma. This mammary gland induration was mammary gland carcinoma.
2.2 Skin induration
A large amount of connective tissue fibers was visible among the tumor cells. The tumor cells were spindle-shaped, varied in size, and arranged in bundles. Individual tumor cells showed a multinucleated giant cell morphology, with deeply stained nuclei and obvious mitotic figures. This skin induration was fibrosarcoma.
3 Surgical treatment
The affected dog was anesthetized with 846 compound, at a dose of 0.1 mL/kg body weight. The surgical site was selected at the upper left part of the affected mammary gland, 1 cm from the mammary gland induration. The surgical site was first shaved, then routinely disinfected. A semicircular incision was made in the skin around the induration, the skin was separated from the induration, and then the connections between the induration and the muscle and fascia were separated. The induration was completely excised, with thorough hemostasis. The skin wound edges were apposed and sutured with interrupted sutures. A drainage tube and gauze drainage were placed at the lowest part of the surgical site.
After excising the mammary gland induration, the band-like skin indurations extending from the affected mammary gland toward the left anterior scapula were excised, and the skin wound edges were apposed and sutured with interrupted sutures.
The excised indurations were subjected to pathological sectioning to observe the histological changes and make a diagnosis.
Postoperative management: 200 mL of normal saline, 2.0 mL of 0.5% Qiang'erxin, 4 mL of ATP, 2.0 mg of dexamethasone, and 2.0 g of ampicillin were mixed and administered in a single intravenous injection for 5 consecutive days. On the 6th day, this was changed to intramuscular injection of Yantongning 2.0 mL per time, twice daily, for 5 consecutive days. The sutures were removed 10 days after surgery, and the wound healed by first intention. Two months later, the dog's owner reported back that the dog had died.
4 Summary
4.1 Mammary gland carcinoma and fibrosarcoma are common malignant tumors in dogs. Diagnosis is mainly based on histopathological changes. This dog developed two malignant tumors successively; the fibrosarcoma occurred after the mammary gland carcinoma, and the skin fibrosarcoma was connected to the mammary gland affected by carcinoma. From the above two points, it can be seen that the fibrosarcoma may have formed after metastasis of cancer cells from the mammary gland carcinoma.
4.2 The key to mammary gland excision is anesthesia and hemostasis. With general anesthesia, the dosage of the anesthetic must be well controlled, especially the initial dose. Along with general anesthesia, local infiltration anesthesia can also be used in combination. Due to the physiological role of the mammary gland, there are relatively many blood vessels connected to it. The vessels come from the lower abdomen, perineum, and groin. The vessels from the lower abdomen and perineum are located superficially and are easy to find, while the vessels from the groin are located deep. These vessels connected to the mammary gland should be found, ligated first, and then the mammary gland should be separated, finally peeling off the entire mammary gland. If hemostasis is not reliable, excessive blood loss during surgery may trigger hemorrhagic shock, which requires special attention.