A 55-yeаr-оld pоstmenоpаusаl woman is evaluated for therapy after a recent diagnosis of breast cancer. She is postmenopausal, and a screening mammogram reveals a new 2.0-cm area of microcalcification in the left breast without any associated mass. She underwent a stereotactic biopsy that showed a moderately differentiated estrogen receptor-negative, progesterone receptor-negative, and HER2-negative infiltrating ductal carcinoma. Her medical history is otherwise negative and she takes no medications. On physical examination, vital signs are normal. There is mild discoloration of the skin resulting from bleeding underneath (ecchymosis) at the site of the breast biopsy but no other palpable masses or detectable left axillary lymphadenopathy. Which of the following is the most appropriate next step in management?
Pleаse use the fоllоwing pаtient vignette tо аnswer questions 18-20. A previously healthy 14-year-old boy is evaluated for acute onset of fever, shaking chills, fatigue, and shortness of breath on exertion. The patient also presents with an occasional, productive cough with thick, purulent sputum. He takes no medications. He is febrile and has tachycardia; the remaining vital signs are normal. Auscultation of the chest reveals inspiratory crackles and bronchial breath sounds. Physical examination of the abdomen is normal, as is the neurological screening examination. Large bruises are observed on both arms and on one of the legs. A radiograph of the chest shows lobar consolidation consistent with pneumonia. Culture of expectorated sputum is positive for S. pneumonia bacteria. Laboratory studies are significant for anemia, and a peripheral blood smear shows greatly increased numbers of immature blast cells. A bone marrow biopsy reveals that 28% of cells are lymphoblastic (reference range: 8-11%). Which of the following is most likely responsible for pneumonia in this patient?