A 42-year-old man who recently immigrated from Mexico presents to the clinic with fever, a productive cough streaked with blood, back pain, and night sweats. He was found to be HIV-positive 3 years ago but does not know his most recent CD4+ count. With further questioning, the patient notes that he had previously experienced these symptoms when he was in Mexico, but he has no recollection of taking any treatment. Which of the following characteristics would best describe the histology of a lung biopsy specimen obtained from this patient?
Q2
A 48-year-old man comes to the physician because of a 2-day history of fever, flank pain, and hematuria. He has chronic back pain, for which he has been taking meloxicam for the past 2 weeks. His temperature is 38.9°C (102°F). Physical examination shows a diffuse maculopapular rash over his trunk and extremities. Urinalysis shows 10–15 RBC/hpf, 20 WBC/hpf, and numerous eosinophils. Histologic examination of a kidney biopsy specimen is most likely to show which of the following findings?
Q3
A 3-year-old boy is brought to the physician for follow-up examination 5 days after sustaining a forehead laceration. Examination shows a linear, well-approximated laceration over the right temple. The wound is clean and dry with no exudate. There is a small amount of pink granulation tissue present. Microscopic examination of the wound is most likely to show which of the following?
Q4
A 9-year-old boy is brought to the hospital by his mother with complaints of fever and right flank pain for the past 3 days. His mom mentions that he has had these symptoms recurrently for the past 4 years. He was treated with antibiotics in the past and got better, but eventually, these symptoms recurred. On physical examination, he is warm to touch and there is tenderness over his right costovertebral angle. The vital signs include a blood pressure of 100/64 mm Hg, a pulse of 100/min, a temperature of 38.0°C (100.4°F), and a respiratory rate of 14/min. Complete blood count results are as follows:
Hemoglobin 12 g/dL
Red blood cell 5.1 million cells/µL
Hematocrit 45%
Total leukocyte count 8,500 cells/µL
Neutrophils 71%
Lymphocyte 24%
Monocytes 4%
Eosinophil 1%
Basophils 0%
Platelets 240,000 cells/µL
Urinalysis results:
pH 6.2
Color turbid yellow
RBC none
WBC 8–10/HPF
Protein trace
Cast WBC casts
Glucose absent
Crystal none
Ketone absent
Nitrite positive
A computed tomography scan shows renal scarring and multiple atrophy sites with compensatory hypertrophy of residual normal tissue. There is additional renal cortical thinning. Which of the following would be the most likely microscopic finding if a renal biopsy were to be done?
Q5
A 60-year-old man comes to the office because of an 8-month history of cough, night sweats, shortness of breath, and fatigue. He has also had a 9-kg (19.8-lb) weight loss during this time. He appears pale. Abdominal examination shows hepatosplenomegaly. His leukocyte count is 80,000/mm3 and his leukocyte alkaline phosphatase level is increased. A peripheral blood smear shows > 82% neutrophils with band forms and immature and mature neutrophil precursors. An x-ray of the chest shows a 9-mm right hilar nodule. Which of the following is the most likely cause of this patient's laboratory findings?
Q6
A 22-year-old man presents with multiple, target-like skin lesions on his right and left upper and lower limbs. He says that the lesions appeared 4 days ago and that, over the last 24 hours, they have extended to his torso. Past medical history is significant for pruritus and pain on the left border of his lower lip 1 week ago, followed by the development of an oral ulcerative lesion. On physical examination, multiple round erythematous papules with a central blister, a pale ring of edema surrounding a dark red inflammatory zone, and an erythematous halo are noted. Mucosal surfaces are free of any ulcerative and exudative lesions. Which of the following statements best explains the pathogenesis underlying this patient’s condition?
Q7
A 68-year-old woman with osteoarthritis comes to the physician because of a swollen and painful right knee for the past 2 days. Temperature is 37°C (98.6°F). Examination shows erythema and swelling of the right knee with a normal range of motion. An x-ray of the right knee shows punctate radiodensities in both menisci and in the joint capsule. Arthrocentesis of the right knee joint yields 5 mL of cloudy fluid with a leukocyte count of 27,000/mm3. Which of the following is the most likely underlying mechanism of this patient's knee pain?
Q8
A 36-year-old woman presents with thyroid swelling. She has been healthy until now and follows all the healthcare precautions except for missing a flu shot this year. On physical examination, the thyroid gland is diffusely enlarged and tender to palpation. Laboratory findings show a decreased serum TSH level and elevated erythrocyte sedimentation rate. Which of the following histopathologic findings would most likely be found in the thyroid gland of this patient?
Q9
A 32-year-old woman presents to her primary care provider complaining of a psoriatic flare that has worsened over the past 2 days. The patient states that her psoriasis is normally well-controlled. She also complains of some fatigue and states that she has recently developed pain and tenderness in the joints of her hands with the right hand being more tender than the left. Her hands are stiff in the morning, and sometimes her fingers swell up. She attributes these changes to her new job where she constantly uses her hands to manufacture cabinets. Physical exam reveals plaques with silvery scale on her elbows and knees. The distal joints of her right hand are mildly swollen and the nails on both hands appear pitted. What is the most likely pathogenesis of her joint pain?
Q10
A 14-year-old girl presents with pain in the right lower quadrant of her abdomen. She describes the pain as sudden, severe, colicky, and associated with nausea and vomiting. Physical exam reveals tachycardia and severe tenderness to palpation with rebound in the right iliac region. Emergency laparotomy is performed which reveals an inflamed appendix. A presurgical blood cell count shows an increase in the number of cells having a multilobed nucleus and multiple cytoplasmic granules as shown in the image below. Which of the following is the main function of these cells?
Inflammation US Medical PG Practice Questions and MCQs
Question 1: A 42-year-old man who recently immigrated from Mexico presents to the clinic with fever, a productive cough streaked with blood, back pain, and night sweats. He was found to be HIV-positive 3 years ago but does not know his most recent CD4+ count. With further questioning, the patient notes that he had previously experienced these symptoms when he was in Mexico, but he has no recollection of taking any treatment. Which of the following characteristics would best describe the histology of a lung biopsy specimen obtained from this patient?
A. Cells with increased nuclear-to-cytoplasmic ratio
B. Noncaseating granuloma
C. Cellular debris and macrophages followed by cystic spaces and cavitation
D. Macrophage filled with fungal microorganisms
E. Epithelioid cells with caseous necrosis surrounded by multinucleated giant cells and lymphocytes (Correct Answer)
Explanation: ***Epithelioid cells surrounded by multinucleated giant cells and lymphocytes***
- The patient's symptoms (fever, productive cough with hemoptysis, back pain, night sweats, HIV-positive status, and history of similar symptoms in Mexico) are highly suggestive of **reactivation tuberculosis (TB)**.
- The characteristic histological finding in **tuberculosis** is **caseating granulomas**, which are composed of epithelioid cells (activated macrophages) surrounded by lymphocytes and multinucleated giant cells (Langhans giant cells), with a central area of **caseous necrosis**.
*Cells with increased nuclear-to-cytoplasmic ratio*
- This description is typical of **malignant cells**, such as those seen in carcinoma, which is not the primary presentation given the historical and symptomatic context pointing towards infection.
- While lung cancer could cause some of these symptoms, the history of previous episodes and HIV points more strongly to an infectious etiology like TB.
*Noncaseating granuloma*
- **Noncaseating granulomas** are characteristic of diseases like **sarcoidosis** or **Crohn's disease**, which typically do not present with the described constitutional symptoms (e.g., night sweats) and hemoptysis in this context, especially with a history of HIV and prior infection.
- The presence of caseous necrosis is a key differentiator for tuberculosis granulomas.
*Cellular debris and macrophages followed by cystic spaces and cavitation*
- This describes the histological features of a **lung abscess** or extensive tissue destruction, which can be a complication of TB but is not the primary defining characteristic of the initial granuloma formation.
- While TB can lead to cavitation, the initial and most specific histological feature in active TB is the granulomatous inflammation.
*Macrophage filled with fungal microorganisms*
- This finding would suggest a **fungal infection** such as histoplasmosis or cryptococcosis, which can occur in HIV-positive individuals and present with similar symptoms.
- However, the strong clinical picture of prior similar illness in Mexico (an endemic area for TB), systemic symptoms, and hemoptysis, makes TB a more probable diagnosis, which is characterized by granulomas rather than direct macrophage colonization by fungi.
Question 2: A 48-year-old man comes to the physician because of a 2-day history of fever, flank pain, and hematuria. He has chronic back pain, for which he has been taking meloxicam for the past 2 weeks. His temperature is 38.9°C (102°F). Physical examination shows a diffuse maculopapular rash over his trunk and extremities. Urinalysis shows 10–15 RBC/hpf, 20 WBC/hpf, and numerous eosinophils. Histologic examination of a kidney biopsy specimen is most likely to show which of the following findings?
A. Interstitial T-cell infiltration (Correct Answer)
B. Cortical cyst formation
C. Glomerular crescent formation
D. Mesangial IgA deposition
E. Papillary necrosis
Explanation: ***Interstitial T-cell infiltration***
- This patient's presentation with **fever**, **rash**, **eosinophiluria**, and acute kidney injury following meloxicam use is highly characteristic of **acute interstitial nephritis (AIN)**.
- AIN is a **type IV hypersensitivity reaction** characterized by inflammation and edema of the renal interstitium, with a predominant infiltrate of **T lymphocytes and eosinophils**.
*Cortical cyst formation*
- **Cortical cysts** are typically associated with **polycystic kidney disease**, which is a genetic disorder presenting with multiple cysts in the renal cortex and medulla, often leading to progressive renal failure over time.
- This condition does not explain the acute onset of **fever, rash, eosinophilia**, and acute kidney injury seen in this patient.
*Glomerular crescent formation*
- **Glomerular crescent formation** is characteristic of **rapidly progressive glomerulonephritis (RPGN)**, indicating severe glomerular injury often due to autoimmune diseases like **Goodpasture syndrome**, vasculitis, or lupus.
- While RPGN can present with **hematuria** and acute kidney injury, the presence of **rash, fever**, and especially **eosinophiluria** strongly points away from a primary glomerular disease and towards an interstitial process.
*Mesangial IgA deposition*
- **Mesangial IgA deposition** is the hallmark of **IgA nephropathy (Berger's disease)**, which typically presents with recurrent episodes of gross or microscopic hematuria, often triggered by an infection.
- It does not usually involve **fever, rash, or significant eosinophilia**, and the acute kidney injury in this case is more indicative of an allergic drug reaction.
*Papillary necrosis*
- **Papillary necrosis** is commonly associated with chronic analgesic abuse (**NSAID use**), **sickle cell disease**, or **diabetes mellitus**.
- While the patient is taking meloxicam, the acute presentation with **fever, rash**, and prominent **eosinophiluria** is a stronger indicator of allergic interstitial nephritis rather than papillary necrosis, which usually presents with chronic pain and hematuria, often with sloughed papillae in the urine.
Question 3: A 3-year-old boy is brought to the physician for follow-up examination 5 days after sustaining a forehead laceration. Examination shows a linear, well-approximated laceration over the right temple. The wound is clean and dry with no exudate. There is a small amount of pink granulation tissue present. Microscopic examination of the wound is most likely to show which of the following?
A. Angiogenesis with type III collagen deposition (Correct Answer)
B. Macrophage infiltration and fibrin clot degradation
C. Fibroblast hyperplasia with disorganized collagen deposition
D. Capillary dilation with neutrophilic migration
E. Acellular tissue with type I collagen deposition
Explanation: ***Angiogenesis with type III collagen deposition***
- Five days post-laceration, the wound is in the **proliferative phase** of healing, characterized by the formation of **granulation tissue**.
- **Granulation tissue** consists of new blood vessels (**angiogenesis**) and proliferating fibroblasts that deposit **type III collagen** (which is later replaced by type I collagen).
*Macrophage infiltration and fibrin clot degradation*
- This describes events characteristic of the **inflammatory phase** (24-48 hours post-injury), where macrophages clean up debris and the initial fibrin clot.
- While some macrophages may still be present, the dominant microscopic feature at 5 days would be granulation tissue formation.
*Fibroblast hyperplasia with disorganized collagen deposition*
- Fibroblast proliferation and collagen deposition are indeed key features of the proliferative phase. However, specifying "disorganized collagen deposition" is somewhat less precise than angiogenesis and type III collagen, and **type III collagen** is characteristic of early granulation tissue rather than just general disorganized collagen.
- This option doesn't fully capture the active angiogenesis component which is prominent in granulation tissue.
*Capillary dilation with neutrophilic migration*
- This is characteristic of the **acute inflammatory response** occurring within the first 24-48 hours after injury.
- By day 5, neutrophils have largely been replaced by macrophages, and the inflammatory phase is transitioning into the proliferative phase.
*Acellular tissue with type I collagen deposition*
- **Type I collagen** deposition and scar maturation (leading to a more acellular tissue) occur much later, during the **remodeling phase** of wound healing, typically weeks to months after the injury.
- At 5 days, the tissue is highly cellular and vascular.
Question 4: A 9-year-old boy is brought to the hospital by his mother with complaints of fever and right flank pain for the past 3 days. His mom mentions that he has had these symptoms recurrently for the past 4 years. He was treated with antibiotics in the past and got better, but eventually, these symptoms recurred. On physical examination, he is warm to touch and there is tenderness over his right costovertebral angle. The vital signs include a blood pressure of 100/64 mm Hg, a pulse of 100/min, a temperature of 38.0°C (100.4°F), and a respiratory rate of 14/min. Complete blood count results are as follows:
Hemoglobin 12 g/dL
Red blood cell 5.1 million cells/µL
Hematocrit 45%
Total leukocyte count 8,500 cells/µL
Neutrophils 71%
Lymphocyte 24%
Monocytes 4%
Eosinophil 1%
Basophils 0%
Platelets 240,000 cells/µL
Urinalysis results:
pH 6.2
Color turbid yellow
RBC none
WBC 8–10/HPF
Protein trace
Cast WBC casts
Glucose absent
Crystal none
Ketone absent
Nitrite positive
A computed tomography scan shows renal scarring and multiple atrophy sites with compensatory hypertrophy of residual normal tissue. There is additional renal cortical thinning. Which of the following would be the most likely microscopic finding if a renal biopsy were to be done?
A. Sloughed tubular cells within tubular lumen
B. Segmental sclerosis and hyalinosis
C. Chronic interstitial inflammation with tubular atrophy and fibrosis (Correct Answer)
D. Tubules containing eosinophilic casts
E. Normal glomeruli with accumulated lipid in proximal convoluted tubular cells
Explanation: ***Chronic interstitial inflammation with tubular atrophy and fibrosis***
- The patient's history of recurrent fevers, flank pain, positive nitrites, WBCs, and WBC casts in urine, along with CT findings of renal scarring and atrophy, points towards **chronic pyelonephritis**.
- The hallmark microscopic findings of chronic pyelonephritis include **chronic interstitial inflammation** (lymphocytes and plasma cells infiltrating the interstitium), **tubular atrophy**, and **interstitial fibrosis**.
- These findings reflect the long-standing inflammatory process and structural damage characteristic of this condition.
*Tubules containing eosinophilic casts*
- This describes **thyroidization of tubules**, which is indeed seen in chronic pyelonephritis when dilated tubules become filled with eosinophilic colloid-like material.
- While this is a characteristic finding, it is more specific but less comprehensive than the broader description of chronic interstitial inflammation with tubular atrophy and fibrosis, which encompasses the fundamental pathologic process.
*Sloughed tubular cells within tubular lumen*
- This finding is characteristic of **acute tubular necrosis (ATN)**, typically seen in ischemic or nephrotoxic injury.
- The patient's presentation with recurrent infections and chronic structural changes is not consistent with ATN.
*Normal glomeruli with accumulated lipid in proximal convoluted tubular cells*
- This description is characteristic of **minimal change disease (lipoid nephrosis)**, a cause of nephrotic syndrome with heavy proteinuria and edema.
- The clinical picture of recurrent infections, flank pain, and localized scarring does not align with minimal change disease.
*Segmental sclerosis and hyalinosis*
- These findings are typical of **focal segmental glomerulosclerosis (FSGS)**, a glomerular disease often presenting with nephrotic syndrome.
- The recurrent infections and localized renal scarring with preserved glomerular function are not consistent with FSGS.
Question 5: A 60-year-old man comes to the office because of an 8-month history of cough, night sweats, shortness of breath, and fatigue. He has also had a 9-kg (19.8-lb) weight loss during this time. He appears pale. Abdominal examination shows hepatosplenomegaly. His leukocyte count is 80,000/mm3 and his leukocyte alkaline phosphatase level is increased. A peripheral blood smear shows > 82% neutrophils with band forms and immature and mature neutrophil precursors. An x-ray of the chest shows a 9-mm right hilar nodule. Which of the following is the most likely cause of this patient's laboratory findings?
A. Sarcoidosis
B. Acute lymphoblastic leukemia
C. Leukemoid reaction (Correct Answer)
D. Tuberculosis
E. Chronic myeloid leukemia
Explanation: ***Leukemoid reaction***
- The combination of **leukocytosis** (>50,000/mm³), **immature granulocytes**, and **elevated leukocyte alkaline phosphatase (LAP) score** in the presence of an underlying inflammatory or infectious process (such as the suspected lung lesion) strongly suggests a leukemoid reaction.
- A leukemoid reaction is a reactive **increase in white blood cells**, often in response to severe infection or malignancy, mimicking leukemia but distinct from it due to the high LAP score and lack of specific chromosomal translocations.
*Sarcoidosis*
- Sarcoidosis typically presents with **non-caseating granulomas**, often affecting the lungs and lymph nodes, but does not usually cause such a profound leukocytosis with immature forms.
- While a **hilar nodule** can be seen, the described hematological findings, especially the high LAP score and pronounced neutrophilia, are not characteristic of sarcoidosis.
*Acute lymphoblastic leukemia*
- This condition involves a proliferation of **lymphoblasts**, not mature or immature neutrophils; therefore, the peripheral smear would show a predominance of blasts and not mature neutrophil precursors.
- While it can cause leukocytosis, the specific cell types and the **elevated LAP score** (LAP is typically low in ALL) rule it out.
*Tuberculosis*
- Tuberculosis can cause fever, night sweats, weight loss, and lung findings, but it typically does not lead to a **leukocyte count of 80,000/mm³** with such a high proportion of immature neutrophils.
- While it can cause a **leukemoid reaction**, the LAP score and specific granulocyte morphology help differentiate it from other causes, and the primary diagnosis here is the reaction itself, which would be *caused* by something like TB.
*Chronic myeloid leukemia*
- CML also presents with marked leukocytosis and **immature myeloid cells** but is characterized by a **low leukocyte alkaline phosphatase (LAP) score** and the presence of the **Philadelphia chromosome (BCR-ABL1 fusion gene)**, which contradicts the elevated LAP score found in this patient.
- While hepatosplenomegaly and constitutional symptoms align, the LAP score is a key differentiating factor.
Question 6: A 22-year-old man presents with multiple, target-like skin lesions on his right and left upper and lower limbs. He says that the lesions appeared 4 days ago and that, over the last 24 hours, they have extended to his torso. Past medical history is significant for pruritus and pain on the left border of his lower lip 1 week ago, followed by the development of an oral ulcerative lesion. On physical examination, multiple round erythematous papules with a central blister, a pale ring of edema surrounding a dark red inflammatory zone, and an erythematous halo are noted. Mucosal surfaces are free of any ulcerative and exudative lesions. Which of the following statements best explains the pathogenesis underlying this patient’s condition?
A. Circulating anti-double-stranded DNA antibodies
B. Tumor necrosis factor (TNF) alpha production by CD4+ T cells in the skin
C. Circulating anti-desmoglein antibodies
D. IgA deposition in the papillary dermis
E. Interferon (IFN) gamma production by CD8+ T cells in the skin (Correct Answer)
Explanation: ***Interferon (IFN) gamma production by CD8+ T cells in the skin***
- This patient's presentation with **target-like skin lesions** following an oral lesion (likely **herpes simplex virus** reactivation) is characteristic of **erythema multiforme (EM)**.
- EM is a **Type IV hypersensitivity reaction** mediated primarily by **CD8+ cytotoxic T cells** that infiltrate the epidermis and cause keratinocyte apoptosis.
- **CD8+ T cells** produce **IFN-gamma** and use perforin/granzyme pathways to destroy virus-infected or antigen-expressing keratinocytes, leading to the distinctive target lesions.
*Circulating anti-double-stranded DNA antibodies*
- This is a hallmark of **Systemic Lupus Erythematosus (SLE)**, which typically presents with a **malar rash**, photosensitivity, arthritis, and organ involvement, none of which are described.
- While SLE can have skin manifestations, the classic target lesions of erythema multiforme are not typical, and the preceding herpes outbreak is not directly linked to SLE.
*Tumor necrosis factor (TNF) alpha production by CD4+ T cells in the skin*
- While **TNF-alpha** is an important pro-inflammatory cytokine involved in many dermatological conditions, it is not the primary cytokine or cellular mechanism driving the specific immune response in **erythema multiforme**.
- Conditions like **psoriasis** involve significant TNF-alpha activity from CD4+ T cells, but their clinical presentation differs significantly from target lesions.
- In EM, the primary effector cells are **CD8+ T cells**, not CD4+ T cells.
*Circulating anti-desmoglein antibodies*
- These antibodies are characteristic of **pemphigus vulgaris**, an autoimmune blistering disease that causes **flaccid bullae** and erosions, particularly on mucosal surfaces.
- The patient's lesions are described as target-like with a central blister, not flaccid bullae, and mucosal surfaces are explicitly stated to be free of lesions, ruling out pemphigus.
*IgA deposition in the papillary dermis*
- This finding is characteristic of **dermatitis herpetiformis**, a pruritic blistering disease associated with **celiac disease**.
- The lesions in dermatitis herpetiformis are typically grouped vesicles and papules, often on extensor surfaces, rather than the target lesions seen in this patient, and are intensely pruritic with no central blister.
Question 7: A 68-year-old woman with osteoarthritis comes to the physician because of a swollen and painful right knee for the past 2 days. Temperature is 37°C (98.6°F). Examination shows erythema and swelling of the right knee with a normal range of motion. An x-ray of the right knee shows punctate radiodensities in both menisci and in the joint capsule. Arthrocentesis of the right knee joint yields 5 mL of cloudy fluid with a leukocyte count of 27,000/mm3. Which of the following is the most likely underlying mechanism of this patient's knee pain?
A. Monosodium urate crystal precipitation
B. Gram-negative diplococci infection
C. Calcium pyrophosphate dihydrate crystal deposition (Correct Answer)
D. Immune complex deposition
E. Noncaseating granuloma formation
Explanation: ***Calcium pyrophosphate dihydrate crystal deposition***
- The presence of **punctate radiodensities** in the menisci and joint capsule on X-ray is characteristic of **chondrocalcinosis**, which is strongly associated with calcium pyrophosphate dihydrate (CPPD) crystal deposition disease (pseudogout).
- The acute onset of a **swollen, painful knee** with a high leukocyte count in the synovial fluid (27,000/mm³) in the context of underlying osteoarthritis is consistent with a pseudogout flare.
*Monosodium urate crystal precipitation*
- While gout (monosodium urate crystal precipitation) also causes acute, painful arthritis with high synovial fluid leukocyte counts, the X-ray finding of **chondrocalcinosis** is not typical.
- Gout commonly presents with abrupt onset pain and swelling, often involving the **first metatarsophalangeal joint**, which is not described here.
*Gram-negative diplococci infection*
- A synovial leukocyte count of 27,000/mm³ falls in a range that could be seen in both inflammatory arthritis and septic arthritis, though **bacterial septic arthritis typically exceeds 50,000/mm³**.
- The key feature distinguishing this case from septic arthritis is the **X-ray finding of chondrocalcinosis**, which is pathognomonic for CPPD deposition disease and not associated with infection.
- Additionally, the patient is **afebrile**, which makes acute bacterial infection less likely.
*Immune complex deposition*
- **Immune complex deposition** can cause inflammatory arthritis (e.g., rheumatoid arthritis, lupus), but these conditions usually involve a more chronic or migratory pattern, and are not directly associated with chondrocalcinosis on X-ray.
- The acute, monoarticular presentation with specific radiologic findings is less suggestive of a primary immune complex-mediated process.
*Noncaseating granuloma formation*
- **Noncaseating granulomas** are characteristic of conditions like sarcoidosis, which can cause arthritis, but this is usually a chronic, often polyarticular, condition.
- This mechanism does not explain the acute, severe monoarticular pain and swelling with chondrocalcinosis seen in this patient.
Question 8: A 36-year-old woman presents with thyroid swelling. She has been healthy until now and follows all the healthcare precautions except for missing a flu shot this year. On physical examination, the thyroid gland is diffusely enlarged and tender to palpation. Laboratory findings show a decreased serum TSH level and elevated erythrocyte sedimentation rate. Which of the following histopathologic findings would most likely be found in the thyroid gland of this patient?
A. Extensive fibrosis of the stroma
B. Mixed cellular infiltration with multinuclear giant cells (Correct Answer)
C. Lymphocytic infiltration with germinal centers
D. Orphan Annie nuclei with psammoma bodies
E. Sheets of polygonal cells in amyloid stroma
Explanation: ***Mixed cellular infiltration with multinuclear giant cells***
- The patient's symptoms of a **diffusely enlarged and tender thyroid**, suppressed **TSH**, elevated **ESR**, and a recent viral illness (missing flu shot) are classic for **subacute granulomatous (De Quervain's) thyroiditis**.
- Histopathologically, this condition is characterized by a **disruptive inflammatory infiltrate** with **multinucleated giant cells** engulfing colloid, surrounded by granulomatous inflammation.
*Extensive fibrosis of the stroma*
- This finding is characteristic of **Riedel's thyroiditis**, a rare form of chronic thyroiditis.
- Riedel's thyroiditis typically presents as a **hard, fixed, and painless goiter**, often leading to compressive symptoms, which does not match this patient's tender goiter.
*Lymphocytic infiltration with germinal centers*
- This pattern is typical of **Hashimoto's thyroiditis**, an **autoimmune thyroid disease**.
- Hashimoto's usually presents with a **painless goiter** and often leads to **hypothyroidism**, not the tender, hyperthyroid-like state seen here.
*Orphan Annie nuclei with psammoma bodies*
- These are hallmark features associated with **papillary thyroid carcinoma**.
- This patient's acute presentation with **tenderness, inflammation**, and temporary hyperthyroidism is inconsistent with a malignant thyroid neoplasm.
*Sheets of polygonal cells in amyloid stroma*
- This describes the histopathology of **medullary thyroid carcinoma**.
- Medullary thyroid carcinoma arises from parafollicular C-cells and is characterized by the production of **calcitonin** and often has a genetic predisposition, which is not suggested by the patient's presentation.
Question 9: A 32-year-old woman presents to her primary care provider complaining of a psoriatic flare that has worsened over the past 2 days. The patient states that her psoriasis is normally well-controlled. She also complains of some fatigue and states that she has recently developed pain and tenderness in the joints of her hands with the right hand being more tender than the left. Her hands are stiff in the morning, and sometimes her fingers swell up. She attributes these changes to her new job where she constantly uses her hands to manufacture cabinets. Physical exam reveals plaques with silvery scale on her elbows and knees. The distal joints of her right hand are mildly swollen and the nails on both hands appear pitted. What is the most likely pathogenesis of her joint pain?
A. Autoantibodies to the Fc portion of IgG
B. Local invasive infection of the joint space
C. Deposition of crystals in the joint space
D. Release of TNF and activation of RANKL pathway (Correct Answer)
E. Repetitive injury
Explanation: ***Release of TNF and activation of RANKL pathway***
- The patient's presentation with psoriasis, **nail pitting**, and **distal interphalangeal (DIP) joint involvement** (more tender on the right, swelling, morning stiffness) is classic for **psoriatic arthritis**.
- **Psoriatic arthritis** is a seronegative spondyloarthropathy characterized by inflammation driven by cytokines like **TNF-α**, which also activates the **RANKL pathway** leading to **bone erosion** and new bone formation.
*Autoantibodies to the Fc portion of IgG*
- This describes **rheumatoid factor (RF)**, which is characteristic of **rheumatoid arthritis (RA)**.
- While both psoriatic arthritis and RA cause joint pain and stiffness, psoriatic arthritis is typically **seronegative** for RF, and RA usually affects the **metacarpophalangeal (MCP)** and **proximal interphalangeal (PIP)** joints, sparing the DIP joints.
*Local invasive infection of the joint space*
- A **septic joint** would present with acute, severe pain, marked swelling, erythema, warmth, and potentially fever, which are not the primary features described here.
- While infection can exacerbate inflammatory conditions, the chronic, migratory, and patterned joint involvement points away from acute bacterial infection.
*Deposition of crystals in the joint space*
- This mechanism is characteristic of **gout** (uric acid crystals) or **pseudogout** (calcium pyrophosphate crystals).
- Crystal arthropathies typically present with severe, acute, monoarticular inflammation, which differs from the described pattern of morning stiffness, multiple joint involvement (even if asymmetric), and an underlying psoriatic flare.
*Repetitive injury*
- While her new job might cause some discomfort, the systemic nature of her symptoms, including a worsening **psoriatic flare**, **fatigue**, **nail pitting**, and **morning stiffness**, suggests an underlying **inflammatory arthropathy** rather than purely mechanical joint pain from overuse.
- **Osteoarthritis** due to repetitive injury typically lacks the inflammatory markers like morning stiffness and associated skin/nail changes seen in this patient.
Question 10: A 14-year-old girl presents with pain in the right lower quadrant of her abdomen. She describes the pain as sudden, severe, colicky, and associated with nausea and vomiting. Physical exam reveals tachycardia and severe tenderness to palpation with rebound in the right iliac region. Emergency laparotomy is performed which reveals an inflamed appendix. A presurgical blood cell count shows an increase in the number of cells having a multilobed nucleus and multiple cytoplasmic granules as shown in the image below. Which of the following is the main function of these cells?
A. Blood clotting
B. Transplant rejection
C. Allergic reaction
D. Phagocytosis (Correct Answer)
E. Antigen presentation
Explanation: ***Correct: Phagocytosis***
- The **multilobed nucleus** and **multiple cytoplasmic granules** are characteristic features of **neutrophils**, the most abundant white blood cells in acute inflammation.
- Neutrophils are the **primary phagocytic cells** in bacterial infections, engulfing and destroying bacteria and cellular debris.
- In acute appendicitis, neutrophilia (increased neutrophil count) is a hallmark finding, reflecting the body's response to bacterial infection.
- The cytoplasmic granules contain enzymes (e.g., myeloperoxidase, lysozyme) used to kill phagocytosed organisms.
*Incorrect: Blood clotting*
- This function is performed by **platelets** (thrombocytes) and clotting factors in the coagulation cascade.
- Platelets are anucleate cell fragments, not cells with multilobed nuclei.
*Incorrect: Transplant rejection*
- Primarily mediated by **T lymphocytes** (CD8+ cytotoxic T cells and CD4+ helper T cells) in cell-mediated immunity.
- This is an adaptive immune response, not the innate response characterized by neutrophil infiltration.
*Incorrect: Allergic reaction*
- Allergic reactions involve **mast cells** (releasing histamine) and **eosinophils** (which have bilobed nuclei, not multilobed).
- Eosinophils are associated with parasitic infections and allergic responses, not acute bacterial infections.
*Incorrect: Antigen presentation*
- Primarily performed by professional **antigen-presenting cells** (dendritic cells, macrophages, and B cells).
- These cells process and present antigens via MHC molecules to activate T cells.
- Neutrophils are **not efficient antigen-presenting cells**; their primary role is immediate pathogen destruction through phagocytosis.