A 45-year-old woman comes to the office for progressive itchiness and fatigue.  She also notes yellowing of the eyes and skin.  Physical examination shows scleral icterus, multiple excoriations on both the upper and the lower extremities, and hepatomegaly.  Laboratory results are as follows:

Liver biopsy reveals dense lymphocytic infiltration of the portal triads, as well as granulomatous destruction of interlobular bile ducts.  Which of the following is the most likely diagnosis?

A 46-year-old woman comes to the emergency department due to 3 days of persistent upper abdominal pain, nausea, and vomiting. The patient has had similar pain in the past, especially after fatty meals, which resolved spontaneously within several hours. Temperature is 38.6 C (101.5 F), blood pressure is 110/65 mm Hg, and pulse is 98/min. BMI is 33 kg/m2. Physical examination is notable for severe right upper quadrant tenderness. Leukocyte count is 21,000/mm3. Laparoscopic surgery is performed and reveals an erythematous, distended gallbladder with patchy necrosis. Which of the following events most likely initiated this patient’s condition?

A 52-year-old woman is evaluated for a 6-month history of progressive fatigue and generalized pruritus.  She has had no significant prior medical conditions or surgery and takes no medications.  The patient does not use tobacco, alcohol, or illicit drugs.  Her sister has Sjögren syndrome.  Physical examination shows skin excoriations and mild hepatomegaly.  Laboratory results are as follows.

The pathogenesis of this patient’s disease process most closely resembles that of which of the following conditions?

A 43-year-old man is evaluated for retrosternal discomfort and dysphagia for the past several months.  He smokes a pack of cigarettes daily and drinks alcohol on weekends.  His BMI is 32.8 kg/m2.  Physical examination is unremarkable.  Esophageal manometry is performed; after a single swallow of 5 mL of water, the tracings appear as shown in the image below.

Which of the following is the most likely diagnosis in this patient?

A 4-week-old boy is brought to the office for a routine well-baby visit.  The boy has been exclusively breastfeeding every 2-3 hours and is making 6 or 7 wet diapers a day.  His urine has appeared dark yellow, and he has had a few pale-colored stools.  His parents also noticed that his skin has appeared yellow for the past 2 weeks, but they were not concerned as they heard from friends that yellow skin is common with breastfeeding.  The patient was born full term without complications by vaginal delivery to a primigravida.  On physical examination, he is well-appearing with icteric sclerae and jaundice of the head and upper chest.  Abdominal examination reveals a mildly enlarged and firm liver.  Liver function results are as follows:

Which of the following is the most likely mechanism for the patient’s presentation?

A 74-year-old man comes to the office due to several months of choking spells, dysphagia, and cough.  He has also had recurrent episodes of pneumonia.  His other medical problems include hypertension and osteoarthritis.  Blood pressure is 130/70 mm Hg.  The patient has foul-smelling breath, but his oropharyngeal and neck examinations are normal.  Cardiopulmonary examination is also normal.  A barium swallow study is performed and reveals an abnormality in the upper esophagus, as shown in the image below.

Which of the following mechanisms is the most likely cause of his symptoms?

A 20-year-old man is evaluated in the clinic due to intermittent episodes of self-resolving jaundice.  His symptoms are not provoked by any particular circumstances or events.  The patient otherwise feels healthy and has no other symptoms.  He does not use tobacco, alcohol, or illicit drugs.  Complete blood count is within normal limits.  Liver function studies are as follows:

Liver biopsy shows abundant pigment inclusions in the lysosomes of the otherwise normal hepatocytes.  Electron spin resonance spectroscopy reveals that the pigment is composed of polymers of epinephrine metabolites.  Which of the following is the most likely cause of this patient’s jaundice?

A 27-year-old woman undergoes laparotomy for right lower quadrant pain and is found to have an inflamed terminal ileum.  The involved segment of the intestine is removed, and the lesion observed on light microscopy is seen in the image.

Which of the following cell types most likely mediated the formation of this patient’s lesion?

A 38-year-old woman comes to the hospital with 4 hours of abdominal pain, nausea, and vomiting.  The pain started in the periumbilical area and is now localized to the right lower quadrant.  Temperature is 38.3 C (100.9 F).  On examination, the patient has right lower quadrant tenderness with guarding.  An appendectomy is performed, and light microscopy of the appendix shows transmural neutrophilic inflammation, consistent with the diagnosis of acute appendicitis.  Further microscopic evaluation reveals abnormal islands of cells, as shown in the image below.

This lesion is most likely derived from which of the following?

A 65-year-old man comes to the office with dysphagia. For the last 3 months, he has relied on protein shakes and juices for nourishment as he has had difficulty swallowing solid foods. He has also had a diminished appetite and an estimated weight loss of 9.1 kg (20 lb). Medical history includes hyperlipidemia, emphysema, and previous episodes of pancreatitis. Family history includes lung cancer in his mother. The patient smoked a pack of cigarettes daily for 50 years but quit 2 years ago. He has been drinking a fifth (750 mL) of vodka weekly for the last decade. Vital signs are normal. BMI is 19.2 kg/m2. Temporal wasting is present but physical examination is otherwise unremarkable. Upper endoscopy reveals a 4-cm mass in the middle third of the esophagus, and several biopsies are taken. Thoracic imaging reveals mediastinal lymphadenopathy. Histologic evaluation of the biopsy specimens will most likely show which of the following in this patient?