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Here are two biopsy results of 2 lumps removed in separate surgeries from the area of the most posterior (inguinal) nipples of an 11 year old female spayed at the age of 7. The first was cancerous, the second benign. She is now 15 (2011) and while an additional mammary lump is being monitored it is unchanging and no further surgeries are contemplated.
Biopsy Single Tissue
HISTOLOGY NUMBER 7-13374
GROSS DESCRIPTION: Received a 4.6 x 1.4 cm section of haired skin and associated mammary tissue. Multiple small firm masses were noted.
MAMMARY GLAND: Involving the mammary gland, there are multiple, variably-sized, moderately cellular, unencapsulated, and well-defined masses. The masses appear to be composed of multiple ductular structures that contain proliferating and disorganized epithelial cells. The cells are cuboidal to polygonal with distinct cell margins and a moderate amount of eosinophilic cytoplasm. The nuclei are cenral, oval, and have finely stippled chromatin and 1-2 prominent eosinophilic nucleoli. Individual cells show prominent karyomegaly and 4-fold anisokaryosis. Frequently within the centers of these lesions, necrosis is a feature. The mitotic rate is variable but in some high power fields, up to 5 mitotic figures are noted. These lesions are encircled by a modest amount of fibrous stroma. Numerous inflammatory cells are noted and include lymphocytes and plasma cells. Small areas of squamous differentiation are seen.
MAMMARY MASS: MAMMARY CARCINOMA WITH SQUAMOUS DIFFERENTIATION
COMMENT: The mass is interpreted to be a malignancy arising within the mammary tissue. Based on histopathology alone, it is difficult to know if there are multiple mammary carcinomas that are developing independently within the mammary ducts or whether this represents infiltrative behavior of a solitary mass. Based on the sections examined, this lesion may have been completely removed but changes do extend close to the tissue margins. For this reason, you may want to periodically monitor this site for recurrence. The owner should also periodically monitor the remainder of the mammary tissue for development of additional masses as dogs that develop one type of mammary tumor frequently go on to develop additional lesions. In the sections of tissue examined, lymphatic invasion is not identified but it still may be prudent to assess the regional lymph nodes. You may also want to consider thoracic radiographs.
Biopsy Single Tissue
HISTOLOGY NUMBER 7-12619
One brown smooth firm fatty irregular mass 2.5 x 2.5 cm.
Two sections of the mass were examined and both exhibit similar findings. There is a large mass of multilobulated well-differentiated adipose tissue interspersed with areas of acute hemorrhage. At one margin of the biopsy is a focus of well-differentiated mammary ducts.
Histopathological changes observed today are compatible with LIPOMA. Lipomas are benign connective tissue tumors composed of histologically normal adipose tissue. It has been postulated that lipomas may represent regions of nodular hyperplasia or altered lipocyte metabolism rather than true neoplasia. Because lipomas have no defined microscopic borders, gross inspection at the time of surgery is a better judge of completeness of resection than microscopic examination. Development of additional lipomas is common. While excision is most often curative, these may recur locally. (References: Veterinary Dermatopathology. pp. 430-431, 1992. Tumors in Domestic Animals. 4th ed. P31. 2001)
Information presented in the “Living With…” sections of the SCARF website represent the personal viewpoint of the individual who made the journal entry and do not represent the opinions, positions, or viewpoints of SCARF or the veterinary community. There may be discussions of drugs, devices, additives, foods, vitamins, herbs or biologicals that have not been approved by the FDA/CVM for the particular use being discussed. SCARF assumes no liability for the accuracy or outcomes of any suggestions, advice or other information provided by the “Living With…” postings on the SCARF website. All treatment decisions should only be made after discussion with your pet’s veterinary health professional, and no changes in your pet’s treatments or diet should be made based on any information found on the SCARF website.