Cutaneous invasive micropapillary carcinoma of probable apocrine sweat gland origin in a cat

Abstract

Abstract. An invasive micropapillary carcinoma (IMC) occurred in the buccal skin of an 18-year-old female cat. Histologically, the tumor had a honeycomb pattern characterized by clusters of neoplastic epithelial cells that were surrounded by empty clear spaces and lined with fibrocollagenous stroma. On immunohistochemistry, the neoplastic cells were positive for cytokeratin (clone CAM5.2; pancytokeratin, clone AE1/AE3) and carcinoembryonic antigen (CEA) but negative for cytokeratin 14, vimentin, S100, smooth muscle actin, and p63. The CEA-positive staining reaction was present along the outermost rim of the neoplastic cell clusters consistent with an "inside-out" immunoreactivity pattern. Examination of the tumor cells by electron microscopy revealed microvilli on the outermost rim of neoplastic cells that were directed toward the surrounding vacant space. Based on histomorphological characteristics, the neoplasm was defined as an IMC of "pure-type." The location site and immunohistochemical features suggest the tumor was most likely derived from the apocrine sweat glands in the buccal skin.

What is your diagnosis? Fine needle aspirate from a cutaneous mass in a cat

“…2 On histopathology, apocrine carcinomas may form solid, tubular, papillary, acinar, or mixed patterns within the dermis, surrounded by a fibrovascular connective tissue stroma. 1,3,4 Surrounding macrophages contain golden-brown cytoplasmic granules composed of lipofuscinlike pigments that are the end-products of lysosomal degradation that are secreted by the apocrine glands. The neoplastic epithelial cells themselves are often pleomorphic with karyomegalic nuclei and lightly eosinophilic cytoplasm that contains secretory granules.…”

Protective Role of Surfactant Protein D in Ocular Staphylococcus aureus Infection

“…To confirm the epithelial cells in tear fluid, IHC analyses were performed with pancytokeratins AE1/AE3 antibody [ 43 , 44 ]. Cells in tear fluid were collected and mounted on slides as described above.…”

“…The cells were fixed with 4%paraformaldehyde for 10 min at room temperature. To perform IHC, the slides were washed with PBS and sequentially incubated at room temperature in PBS containing goat serum for 10 min, and then monoclonal pancytokeratin AE1/AE3 primary antibody at 1:50 dilution (DakoCytomation, Carpinteria, CA) for 1h [ 44 ]. After the reaction with the primary antibodies, the cells were incubated with biotinylated goat anti-rabbit IgG secondary antibodies.…”