A 62-year-old woman comes to the physician after finding a lump in her breast. Physical examination reveals a firm, immovable, irregularly shaped mass. Mammography is performed and shows a spiculated, calcified lesion that was not seen on prior studies. A tissue biopsy is diagnostic for infiltrating ductal carcinoma. Malignant tumors such as infiltrating ductal carcinoma are typically associated with varying degrees of disordered differentiation and maturation. Which of the following findings is most characteristic of an anaplastic tumor?

Question

A 62-year-old woman comes to the physician after finding a lump in her breast.  Physical examination reveals a firm, immovable, irregularly shaped mass.  Mammography is performed and shows a spiculated, calcified lesion that was not seen on prior studies.  A tissue biopsy is diagnostic for infiltrating ductal carcinoma.  Malignant tumors such as infiltrating ductal carcinoma are typically associated with varying degrees of disordered differentiation and maturation.  Which of the following findings is most characteristic of an anaplastic tumor?

Quizplus · Accepted Answer

Well differentiated (low-grade) tumors contain neoplastic cells that are morphologically and architecturally similar to normal cells in the tissue of origin. In contrast, poorly differentiated (high-grade) tumors contain neoplastic cells that lack most of the characteristic features of the original tissue. Neoplasms that contain cells in the midst of this spectrum are termed moderately differentiated (medium-grade). Neoplastic cells that demonstrate a complete lack of differentiation are termed anaplastic. Anaplastic tumors typically demonstrate the following features: (Choices B and E) The production of keratin pearls by skin tumor cells is an example of dysplasia (ie, disordered growth). The fact that they produce keratin means that the tumor cells are well differentiated. Bronchial epithelial cells can also produce keratin pearls after undergoing a phenotypic switch from columnar epithelium to squamous epithelium. The process of switching from one differentiated cell type to another is known as metaplasia and often occurs in response to irritants (eg, tobacco smoke or gastric acid). (Choices C and D) Cells in the colon normally form goblet cell-containing glands and cells in hepatic tissue normally synthesize bile. Therefore, the described tumor cells would be well-differentiated, not anaplastic. Educational objective: Undifferentiated (anaplastic) tumors bear no resemblance to the tissue of origin. They are composed of pleomorphic cells with large, hyperchromatic nuclei that grow in a disorganized fashion. Anaplastic tumors may also contain numerous, abnormal mitoses and giant tumor cells.

A 62-Year-Old Woman Comes to the Physician After Finding a Lump