A 36-year-old woman arrives at the office after becoming aware of small lumps beneath her arm as she dressed. She says that she feels well and is symptom-free. The significance of her medical history for hypothyroidism. Negative family history. Her body mass index, as determined by a physical examination, is 24 kg/m². An examination of the breast reveals non-tender left axillary lymphadenopathy. An ultrasound-guided biopsy is performed on the patient. Microscopy of the tissue specimen shows clumps of cells that have positive immunohistochemical staining for cytokeratin. These cells most likely belong to which of the following lineages?

Question

Quizplus · Accepted Answer

Eductional Objective: The proteins known as cytokeratins aid in the formation of the intermediate filaments that include keratin and make up the cytoskeleton of practically all epithelial cells. Keratin proteins are relatively numerous in exposed stratified squamous epithelium, including the oral mucosa and epidermis, and less prevalent but still present in simple epithelium, including that found in the liver, intestine, and pancreas. Consequently, cytokeratin is a frequently employed immunohistochemical marker for malignancies arising from epithelial cells, such as breast cancer. The main protein in both hair and nails is keratin.

A 36-Year-Old Woman Arrives at the Office After Becoming Aware