Grossly the animals revealed poor body condition and a large growth in abdomen (Fig 1a). On necropsy examination it was found that the observed growth were solid and about 2-3cm across (Fig 1a) and had large, dark patches resembling hemorrhages (Fig 1a and b). On cutting the tumor masses there was oozing of copious amounts of dark colored blood.
@figure1
The H & E stained section of the tumor revealed variable histopathological manifestations in different region. Some of the region revealed atypical acinar pattern composed of small clusters of cells organized around a small lumen. Faint evidence of secretions was also there in these acini. The cells and their nuclei revealed remarkable pleomorphism (Fig 2). This region could be classified as Dunn type-A mammary tumor with acinar pattern (
Dunn, 1959;
Sass and Dunn, 1979) or by Annapolis nomenclature as adenoma/carcinoma of mammary gland
(Cardiff et al., 2000). While in some parts the tumor parenchyma revealed solid cords of pleomorphic tumor cells with little, but generally no gland formation. The nuclei were large, extremely pleomorphic, vesicular and had multiple nucleoli (Fig 3). This region could be classified as Dunn type B tumor or solid mammary carcinoma, low grade
(Dunn, 1959;
Sass and Dunn, 1979), while by Annapolis nomenclature it was classified as solid tumor of mammary gland
(Cardiff et al., 2000).
@figure2
@figure3
Most remarkable finding was presence of cavernous hemangioma (Fig 4 and 5). In some regions of the mammary tumor there were numerous large atypical endothelium lined cavernous spaces filled with pink staining homogenous hyaline plasma and few erythrocytes embedded in them (Fig 5). They were numerous and variable in size but all had pinkish homogenous hyaline content (plasma) with few embedded erythrocytes in them. In certain foci only a thin line of endothelium was partitioning a cavern.
@figure4
@figure5
The gross morphology of mammary tumor was very similar to earlier reported mammary tumor in other rodents (
Percy and Barthold, 2007;
Thangapandiya et al., 2011). On histopathological analysis some parts of the mammary tumors could be diagnosed as Dunn type-A mammary tumor with acinar pattern (
Dunn, 1959;
Sass and Dunn, 1979) and by Annapolis nomenclature as adenoma/carcinoma of mammary gland
(Cardiff et al., 2000). While in some other parts Dunn type B tumor or solid mammary carcinoma, low grade (
Dunn, 1959;
Sass and Dunn, 1979) and by Annapolis nomenclature as solid tumor of mammary gland
(Cardiff et al., 2000) could be diagnosed. This finding reinforces that a single tumor mass may show variable differentiation in different parts.
Hemangioma of mammary glands with or without breast cancer have been reported in human beings
(Kim et al., 2006; Kawatra et al., 2009; Rajdeo et al., 2015). The hemangiomas are often described as ´blood blisters’ especially if they are superficial. In a case of concurrent breast fibroadenoma and hemangioma in human female, they appeared as severely congested areas of brown color
(Kawatra et al., 2009). While in another case there was oozing of dark colored blood on attempting the biopsy
(Kim et al., 2006). The studied mice tumors revealed similar gross findings of large dark patches on surface like blood blisters and blood filled cavities.
A cavernous hemangioma is histopathologically characterized by large cavernous spaces filled with RBCs embedded in fibrinous matrix or coagulated plasma. The wall of the cavernous structure can be lined by a single layer of endothelial cells or sometime the cells of affected organ. The cavernous space may reveal thrombosis. Depending of duration and trauma the hemangioma shows progressive fibrosis of the walls. In later stages numerous anastomosing caverns are developed with thick fibrosed walls (
Winer. 1952). Accordingly, the presented case reveals cavernous hemangioma lined with only thin layer of endothelium as earlier reported in cutaneous and ovarian tumors of human beings (
Winer, 1952;
Dahal et al., 2018). Perusal of available literature did not reveal any report of hemangioma in mouse mammary gland, but the observed histomorphology of cavernous hemangiomas was similar to earlier published reports (
Winer, 1952;
Booth and Sundberg, 1995;
Hardisty et al., 2007; Dahal et al., 2018). However, it was found that natural and induced hemangiomas in mice had been reported associated with skin, liver, pancreas, stomach, intestines, adipose tissue, sub-cutis, uterus, seminal vesicles, muscle tissue, bone marrow, spleen and cerebellum (
Booth and Sundberg, 1995;
Hardisty et al., 2007; Kakiuchi-Kiyota et al., 2013).
