A 36-year-old man presents to your office with persistent fever, bleeding gums, and a sore throat.  Peripheral blood microscopy findings are shown in the image below.

These cells contain structures that would stain positive for which of the following?

A 63-year-old man comes to the emergency department due to abdominal pain.  Physical examination shows abdominal tenderness without guarding or rebound.  His laboratory test results are as follows:

On further investigation, magnetic resonance angiography of the abdomen reveals mesenteric vein thrombosis.  Flow cytometry shows absence of CD55 on the surface of red blood cells.  Which of the following is the most likely pathologic renal finding in this patient?

A 64-year-old man comes to the office due to 3 months of constant, dull, low back pain that is worse with movement.  The patient has also had intermittent episodes of difficult urination over the last year.  He has no other medical conditions and takes no medications.  The patient smoked a pack of cigarettes daily for 15 years but quit 10 years ago.  Vital signs are within normal limits.  On physical examination, the lungs are clear and heart sounds are normal.  The abdomen is soft and nontender with no hepatosplenomegaly.  Digital rectal examination shows a diffusely enlarged prostate with no nodules.  Laboratory testing reveals a serum creatinine level of 1.9 mg/dL.  Urine dipstick testing is within normal limits, but 24-hour urinary protein excretion is elevated.  Urine microscopy shows waxy, laminated casts.  Imaging of the spine demonstrates diffuse osteopenia and multiple irregular, radiolucent lesions in the thoracic and lumbar vertebrae.  Which of the following histopathologic findings is most likely associated with the development of this patient’s bone lesions?

A 7-year-old boy is brought to the office due to easy bruising and frequent epistaxis for 2 weeks.  Temperature is 36.7 C (98 F), blood pressure is 106/60 mm Hg, pulse is 94/min, and respirations are 18/min.  Examination shows pale lips with mucositis in the oropharynx.  The neck is supple.  The abdomen is soft, and pulses are 2+.  Laboratory results are as follows:

Findings from a bone marrow biopsy are shown in the image below:

Which of the following is the most likely diagnosis?

A 26-year-old woman is being evaluated for glomerulonephritis, a photosensitive skin rash, and arthralgia.  Rapid plasma reagin (RPR) test is repeatedly positive despite negative Treponema pallidum enzyme immunoassay (TP-EIA) testing.  Coagulation study results are as follows:

This patient is at greatest risk for which of the following complications?

A 25-year-old woman comes to the office due to significant fatigue.  Several weeks ago, the patient had a weeklong episode of intermittent fever and severe body aches.  Over the last 2 weeks, she has been too tired to complete her normal jogging routine in the mornings and has had to take naps after returning home from work.  The patient has no chronic medical conditions and takes no medications.  Temperature is 37.2 C (99 F), pulse is 110/min, and respirations are 20/min.  Examination shows pale lips and conjunctivae.  The abdomen is soft and there is no hepatosplenomegaly.  Examination of the extremities is unremarkable, and no lymphadenopathy is present.  Laboratory results are as follows:

Peripheral blood smear reveals normocytic, normochromic red blood cells, and other cell types appear morphologically normal.  This patient’s bone marrow biopsy would most likely show which of the following patterns?

A 6-year-old boy is brought to the emergency department due to bleeding after a dental extraction earlier this morning.  The patient’s past medical history is significant for painful swelling of his knee joints after minor trauma.  Aspiration of the joints during several occasions yielded frank blood, and he was diagnosed with hemarthrosis.  He has no known allergies.  Currently, hemostasis in this patient most likely can be achieved by the administration of which of the following?

A 59-year-old woman comes to the office due to progressive fatigue and occasional heart palpitations over the last 6 months.  The patient has been under a lot of stress recently due to problems at work.  She has no dietary restrictions, eats out at restaurants frequently, and drinks 2 or 3 cans of beer on the weekends.  The patient is postmenopausal and has not noticed any uterine bleeding, dark stools, or bleeding with bowel movements.  Her BMI is 25 kg/m².  Hemoglobin is 8.5 g/dL.  Peripheral blood smear reveals pale, microcytic erythrocytes.  Which of the following is the most likely underlying cause of this patient’s abnormal laboratory findings?

A 45-year-old man comes to the office for progressive weakness and fatigue over the last year.  The patient was adopted and does not know his family history.  After a comprehensive physical examination and laboratory evaluation, the patient undergoes genetic testing.  A loss of expression mutation is identified in a gene coding for a protein found on the basolateral surface of hepatocytes and enterocytes.  The protein is known to interact with the transferrin receptor.  Which of the following conditions is this patient at greatest risk of developing?

A 59-year-old man comes to the office due to 3 months of progressive fatigue and back pain.  The back pain occurs mainly with movement or positional changes.  Physical examination reveals midline tenderness over the middle and lower back.  Laboratory evaluation shows a hemoglobin level of 10.2 g/dL and serum calcium level of 12 mg/dL.  A bone marrow aspirate is performed, and the histopathologic findings are shown below.

This patient is at greatest risk for developing which of the following conditions?

A 25-year-old woman comes to the office due to arthralgias in her hands for the last several months.  The pain frequently involves her wrists and proximal finger joints bilaterally, and alternates between being worse in the wrists versus in the hands.  The patient has no other medical problems and takes no medications.  Complete blood count results are as follows:

Further evaluation reveals proteinuria and red blood cell casts.  Which of the following is the most likely diagnosis?

A 45-year-old man comes to the office due to a week of purulent nasal discharge, headache, sore throat, and nonproductive cough.  He has no significant past medical history except for an episode of infectious mononucleosis at age 22.  The patient smokes a pack of cigarettes daily.  His temperature is 38 C (100.4 F).  He has maxillary sinus tenderness, pharyngeal erythema, and tender anterior cervical lymphadenopathy.  Laboratory results are as follows:

The leukocyte alkaline phosphatase score is low.  Which of the following is the most likely diagnosis?

A 35-year-old woman comes to the hospital due to sudden-onset numbness in her left arm and face.  The patient has had generalized headache, dyspnea on exertion, and easy fatigability for several days but no weakness.  She has a history of well-controlled asthma.  Temperature is 37.7 C (99.9 F), blood pressure is 110/60 mm Hg, and pulse is 80/min.  Light touch sensation is decreased in the left upper extremity and the lower left side of the face.  Strength and reflexes are normal.  Cardiopulmonary and abdominal examinations are unremarkable.  There is no skin rash.  Laboratory results are as follows:

PT and PTT are normal.  Peripheral blood smear shows numerous schistocytes.  Urinalysis is positive for mild proteinuria.  Which of the following is the most likely underlying cause of this patient’s current condition?

A 4-year-old boy is admitted to the hospital due to shock and subsequently dies from overwhelming sepsis.  Examination during autopsy shows hepatosplenomegaly.  Clumps of erythroid precursor cells are seen in the liver and spleen.  The presence of these precursor cells is most likely due to which of the following underlying conditions?

A 2-week-old girl is brought to her primary care provider for a routine visit.  The patient was born by normal spontaneous vaginal delivery at 39 weeks gestation.  The mother is breastfeeding exclusively, and the infant has regained her birth weight.  Newborn screening results from hemoglobin electrophoresis are as follows:

The patient’s mother has sickle cell trait, and a maternal cousin has sickle cell anemia.  Examination shows a well-appearing infant with no pallor or splenomegaly.  Which of the following is most likely true about this patient?

A 12-year-old girl is brought to the emergency department due to several days of worsening exertional dyspnea and lethargy.  The patient has a history of sickle cell disease and takes hydroxyurea.  Physical examination shows mucosal pallor and a systolic ejection murmur.  Laboratory studies reveal a hemoglobin level of 5.6 g/dL.  Bone marrow biopsy is performed and demonstrates decreased erythroid precursors and giant pronormoblasts containing inclusions, as shown below.

Which of the following is the most likely cause of this patient’s current condition?

A 63-year-old man comes to the office due to fatigue and easy bruising.  He has no lymphadenopathy on physical examination.  Laboratory results are as follows:

The patient’s peripheral blood smear is shown in the image below:

Which of the following is the most likely diagnosis?

A 52-year-old man comes to the physician complaining of dizziness, headaches, and pruritus after showering.  He has smoked half a pack of cigarettes daily for the past fifteen years and drinks alcohol socially.  Physical examination shows a reddish facial complexion and mild splenomegaly.  Laboratory results are as follows:

Which of the following is the most likely cause of this patient’s findings?

A 24-year-old, previously healthy woman comes to the hospital due to a 3-day history of fever, dyspnea, and cough productive of yellow sputum.  Temperature is 38.8 C (101.8 F), blood pressure is 110/66 mm Hg, and pulse is 110/min.  The patient has bronchial breath sounds and crackles over the right lower lung.  Laboratory results are as follows:

The leukocyte alkaline phosphatase test score is elevated.  Which of the following is the most likely finding on this patient’s peripheral blood smear?

A 54-year-old previously healthy man comes to the clinic after 2 months of progressive, generalized weakness and easy fatigability.  He also has abdominal discomfort and early satiety.  The patient works as a security advisor and has not traveled recently.  He is afebrile and other vitals signs are normal.  On examination, he has pallor, abdominal distension, and massive splenomegaly with the spleen tip crossing the midline.  No peripheral lymphadenopathy is present.  Peripheral blood cell count shows pancytopenia.  Bone marrow aspiration is attempted, but no marrow can be aspirated.  Which of the following findings is most likely to be seen in this patient?

A 16-year-old girl comes to the office due to fatigue for the past few months.  She attends high school and plays on the school soccer team but says that her endurance has decreased.  The patient sleeps 9 hours a night and has been a vegetarian for the past 6 months.  She reached menarche at age 13 and has had regular menses for the past 6 months.  Blood pressure is 110/60 mm Hg, pulse is 70/min, and BMI is 21 kg/m².  Physical examination shows a well-nourished teenage girl with pale conjunctivae.  Hemoglobin is 9.2 g/dL.  Which of the following sets of additional laboratory findings are most likely to be seen in this patient?

A 61-year-old man comes to the office due to 4 months of easy fatigability, anorexia, and a 4.5-kg (10-lb) unintentional weight loss.  His stool occult blood testing is positive, and laboratory studies show microcytic hypochromic anemia.  Colonoscopy reveals a 6-cm (2.4-in) mass in the descending colon.  Biopsy samples obtained during the procedure are consistent with adenocarcinoma.  A subsequent CT scan of the abdomen shows multiple metastatic liver lesions.  Therapy with monoclonal antibodies that bind to epidermal growth factor receptors on the malignant cells is considered.  An activating mutation in which of the following will most likely make this therapy ineffective?

A 26-year-old woman, gravida 2 para 1, at 8 weeks gestation comes to the office due to pain and swelling of her left leg for the past day.  The patient had a pulmonary embolism during her previous pregnancy, and prophylactic low-molecular-weight heparin therapy was initiated 6 days ago.  She has no other medical conditions and takes prenatal vitamins.  Physical examination shows left lower extremity edema and calf tenderness but no other abnormalities.  Venous duplex ultrasonography reveals acute left femoral vein thrombosis.  Platelet count, which was normal prior to anticoagulant therapy initiation, is 84,000/mm³.  Other blood cell counts and renal and liver function studies are within normal limits.  Which of the following most likely predisposed this patient to her current condition?

A 72-year-old woman comes to the office for a routine follow-up appointment.  She has no symptoms and her past medical history is insignificant.  Her temperature is 36.7 C (98 F), blood pressure is 110/80 mm Hg, and pulse is 76/min and irregular.  ECG shows atrial fibrillation with no ischemic changes.  Anticoagulation therapy with warfarin is initiated for stroke prevention.  Two days later, the patient is hospitalized with severe skin and subcutaneous fat necrosis.  Drug effects on which of the following processes are most likely responsible for this patient’s skin findings?