Question 57 — Cerebral Embolism, Vessel Occluded

Question 58 — Right Eye Ptosis + Diplopia Differential

• Diplopia is intermittent, variable, and not confined to a single cranial nerve distribution
• Pupils are always normal (distinguishing it from CN III palsy)
• Fatigable ptosis on sustained upgaze is characteristic
• Many patients have purely ocular MG without systemic weakness
• Confirmed classically by edrophonium (Tensilon) test or anti-AChR antibodies

• Lambert-Eaton causes proximal limb weakness, not prominent ptosis/diplopia; autonomic features present; caused by anti-VGCC antibodies (paraneoplastic)
• Thyrotoxic myopathy causes proximal muscle weakness, not ptosis + diplopia as a primary feature
• Alcohol myopathy causes proximal limb weakness, no ocular involvement

Question 59 — Spindle Cells in Herringbone Pattern

• Rhabdomyosarcoma: shows rhabdomyoblasts with eosinophilic cytoplasm; embryonal type shows small round cells; alveolar type has alveolar pattern
• Liposarcoma: shows lipoblasts (cells with scalloped, indented nucleus by cytoplasmic lipid vacuoles)
• Angiosarcoma: shows anastomosing vascular channels lined by atypical endothelial cells

Question 60 — True Statement About Gout

• A. Langhans giant cells: seen in tuberculosis and other granulomatous diseases; gout has foreign-body type giant cells, not Langhans giant cells
• B. Calcium pyrophosphate deposit: this describes pseudogout (calcium pyrophosphate deposition disease / CPPD), not gout
• D. Proliferation of mononuclear cells: while mononuclear cells participate in tophus formation, this is not a characteristic/defining feature of gout; it is nonspecific

Question 61 — Rib Tumor: Sclerotic Ring, Ground Glass, Chinese Character Trabeculae

• Cemento-ossifying fibroma: has osteoblastic rimming around trabeculae (distinguishing it from fibrous dysplasia); occurs predominantly in jaw bones
• Desmoplastic fibroma: locally aggressive fibromatosis of bone; shows dense collagen bundles with bland spindle fibroblasts, no woven bone trabeculae
• Nonossifying fibroma: shows storiform pattern of spindle cells with scattered multinucleated giant cells and foamy histiocytes; purely lytic on imaging, no bone formation

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q57 — Cerebral Embolism

Robbins notes that the MCA is the most frequently occluded vessel in embolic stroke, and that rheumatic heart disease with AF is a classic cardioembolic etiology producing left atrial thrombi that embolize to the cerebral circulation.

Q58 — Ptosis + Diplopia Differential

• Ptosis and diplopia are the most common initial presentation (ocular MG)
• Fatigability — weakness worsens with repeated use, improves with rest
• Pupils are spared (purely motor end-plate disease)
• Thymoma or thymic hyperplasia is associated

Q59 — Herringbone Pattern, Spindle Cells

• Spindle-shaped fibroblastic cells arranged in interlacing fascicles
• Herringbone (fascicular/chevron) pattern — the pathognomonic arrangement where alternating bundles intersect at acute angles
• Variable collagen production between cells
• Minimal pleomorphism in well-differentiated forms

Q60 — True Statement About Gout

Tophi are deposits of monosodium urate (MSU) monohydrate crystals surrounded by a granulomatous reaction of foreign-body giant cells, mononuclear cells, and fibrosis. They occur in soft tissues, periarticular structures, synovium, and cartilage.

• A. Langhans giant cells: These are multinucleated giant cells with peripheral nuclear arrangement seen in tuberculosis and sarcoidosis. Gout has foreign-body type giant cells (nuclei scattered centrally), not Langhans type.
• B. Calcium pyrophosphate deposit: This is the defining feature of pseudogout (CPPD disease), not gout. Gout deposits monosodium urate.
• D. Proliferation of mononuclear cells: Nonspecific; not a defining or characteristic feature of gout.

Q61 — Rib Tumor: Ground Glass, Sclerotic Rim, Chinese Character Trabeculae

Fibrous dysplasia is characterized by replacement of normal bone and marrow by fibrous tissue containing irregular trabeculae of immature woven bone. The bony trabeculae lack osteoblastic rimming and are described as resembling "Chinese letters" or alphabet soup due to their curvilinear, irregular arrangement.

• Ground-glass appearance — due to the mixture of fibrous tissue and mineralized matrix
• Sclerotic rind/shell — reactive peripheral sclerosis
• Well-defined border

Summary

Note: Robbins Textbook of Pathology was not available as a retrievable document in the medical database at the time of this query. These answers are drawn from the well-established content of Robbins & Cotran Pathologic Basis of Disease (10th edition) from my training knowledge, with concepts that are consistent across editions.

Robbins Textbook of Pathology — Referenced Answers

Q63 — Osteosarcoma: Which Statement is NOT TRUE?

Q64 — Osteoarthritis: Underlying Mechanism

Repeated mechanical stress causes chondrocyte injury and release of cartilage matrix fragments. These fragments stimulate chondrocytes and synovial cells to secrete matrix metalloproteinases (MMPs) — especially collagenases (MMP-1, MMP-13) and aggrecanases (ADAMTS-5) — which progressively degrade the extracellular matrix of hyaline cartilage, leading to fibrillation, fissuring, and eventual erosion.

Q65 — COPD Encompasses Which Two Conditions?

1. Emphysema — permanent, abnormal enlargement of airspaces distal to the terminal bronchiole, with destruction of alveolar walls, without obvious fibrosis
2. Chronic Bronchitis — clinically defined as persistent productive cough for at least 3 consecutive months in at least 2 consecutive years, caused by mucous gland hypertrophy (Reid index >0.5) and goblet cell metaplasia in bronchioles

• Asthma is a separate obstructive disease characterized by reversible airflow obstruction and airway hyperreactivity — it is not classically included under COPD
• Chronic Bronchiolitis and Chronic Pneumonia are not the standard WHO/Robbins COPD components

Q66 — Red Hepatization of Lobar Pneumonia

• A → Red Hepatization ✓ (correct answer)
• B → Congestion stage
• C → Grey Hepatization
• D → Resolution stage

Q67 — Miner Found Dead: Black Discolorations in Lungs

• Mine worker (coal mine) → chronic inhalation of carbon/coal dust
• Black discolorations on lung surface and cut sections = carbon pigment deposits in macrophages and lymphatics
• Robbins describes anthracosis as the most common form of pneumoconiosis, occurring to some degree in virtually all urban dwellers and smokers

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q68 — Type of Emphysema in a Heavy Smoker

The pursed-lip breathing and hunched-forward "pink puffer" posture are classic features Robbins associates with emphysema — specifically the centriacinar type in smokers.

Q69 — Horner Syndrome in a Heavy Smoker

Note: Historically squamous cell carcinoma was the classic Pancoast tumor, but Robbins and current literature recognize adenocarcinoma as increasingly common at the apex. Among the given choices, only option C places the tumor at the apex — the required anatomical location for Horner syndrome.

Q70 — Pneumothorax: Mediastinal Position

Robbins: In tension pneumothorax, increased intrapleural pressure on the affected side displaces the mediastinum contralaterally, compressing the opposite lung and great vessels.

• Simple/traumatic pneumothorax: mediastinum shifts left (away from right-sided air)
• If tension pneumothorax develops: the shift is more dramatic and compromises venous return

Q71 — MI at 24–48 Hours: Histological Findings

• A. Granulation tissue → weeks 1–3
• C. Plasma cell infiltrates → not a typical MI feature (plasma cells = chronic immune reaction)
• D. Fibroblastic proliferation → weeks 1–3

Q72 — Friable, Bulky, Bacteria-Laden Vegetations

Robbins: The hallmark of infective endocarditis is bulky, destructive vegetations composed of necrotic debris, thrombus, and masses of organisms, capable of causing valve perforation and systemic septic emboli.

Q73 — Best Serum Markers to Exclude Acute MI

• Troponin I has the highest sensitivity and specificity for myocardial necrosis; elevated levels persist for days, helping diagnose even delayed presentations
• CK-MB provides early confirmation and helps time the infarct
• Together, a normal Troponin I + normal CK-MB effectively excludes AMI

• Myoglobin: rises earliest but is non-specific (present in skeletal muscle); alone insufficient to exclude MI
• CK-BB: brain isoform — not used in cardiac evaluation
• Troponin I + CK-BB: CK-BB adds no cardiac diagnostic value

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q74 — Congo Red "Salmon Pink" Deposits in Cardiac Tissue

Robbins: Amyloidosis of the heart manifests as restrictive cardiomyopathy. Congo red stain demonstrates the amorphous eosinophilic (salmon pink) deposits; under polarized light they exhibit apple-green birefringence.

Q75 — Tearing Back Pain, Aortic Regurgitation, Hypotension: Pathogenesis

Robbins: Hypertension (present in ~70% of dissection patients) combined with intrinsic medial weakness from cystic medial degeneration allows blood to dissect through the aortic wall layers.

Q76 — Cyanotic Infant, Boot-Shaped Heart

Robbins: The boot-shaped cardiac silhouette results from RVH causing upward displacement and rounding of the cardiac apex, combined with a concave pulmonary artery segment (due to reduced pulmonary flow).

• B lists ASD (not VSD) — ToF has VSD, not ASD
• C describes LVH — ToF produces right ventricular hypertrophy
• D lists ASD and LVH — both incorrect for ToF

Q77 — "Piecemeal Necrosis" Definition

The destruction of the limiting plate — the single layer of hepatocytes that borders the portal tract — with progressive necrosis of periportal hepatocytes extending into the lobule. It is the hallmark histological feature of chronic active hepatitis (autoimmune hepatitis, chronic viral hepatitis B and C).

Q78 — Hirschsprung Disease: Location of Aganglionic Segment

The aganglionic segment lacks peristaltic activity and remains in a state of tonic contraction, causing a functional obstruction. The bowel proximal to this segment becomes massively dilated and hypertrophied (the "megacolon") due to accumulation of feces. The dilated portion is ganglionic (normal); the narrow, contracted, distal segment is aganglionic (abnormal).

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q79 — True Statement Regarding Omphalocele

Robbins key distinction: Omphalocele = sac present; Gastroschisis = no sac (organs free in amniotic fluid).

Q80 — Gastric Mass: CD117 Positive, SMA Negative, Spindle Cells

• Spindle-shaped cells
• CD117 (c-kit) positivity
• SMA (smooth muscle actin) negativity

• Leiomyoma: SMA positive, CD117 negative — a smooth muscle tumor
• Diffuse Large B Cell Lymphoma: lymphoid cells, not spindle cells; CD20+
• Carcinoid tumor: neuroendocrine; chromogranin/synaptophysin positive; not spindle cells with CD117

Q81 — Hepatic Vein Thrombosis with RUQ Pain, Hepatomegaly, Ascites

1. Hepatomegaly (congestive)
2. Ascites (portal hypertension)
3. Abdominal pain (RUQ)
4. Hematemesis (from esophageal varices due to portal hypertension)

Q82 — Well-Demarcated Liver Lesion with Central Stellate Scar and Bile Duct Proliferation

A well-demarcated, non-encapsulated liver mass with a central stellate fibrous scar containing a large artery with eccentric fibrous thickening. Radiating fibrous septa divide the lesion into hepatic nodules. Proliferating bile ducts within the fibrous septa are a key histological feature. No malignant cells are present.

Q83 — Dark Urine After OCPs, Jaundice, Elevated Direct Bilirubin, Pigmented Hepatocyte Globules, MRP2 Mutation

• Autosomal recessive
• Mutation in MRP2 (ABCC2) gene — the multidrug resistance protein 2 responsible for transporting conjugated bilirubin (bilirubin glucuronide) across the hepatocyte canalicular membrane into bile
• Result: impaired excretion of conjugated bilirubin → elevated serum direct (conjugated) bilirubin → conjugated bilirubinuria (dark urine)
• Pathognomonic finding: coarse, dark brown/black pigmented granules in hepatocyte cytoplasm (melanin-like pigment)
• Triggered/worsened by oral contraceptives or pregnancy (which increase bilirubin load)

Robbins: MRP2 mutation → failure of canalicular conjugated bilirubin excretion → conjugated hyperbilirubinemia with characteristic hepatocyte pigmentation.

• A. GGT synthesis unaffected — MRP2 is a transporter, not a synthetic enzyme
• C. Albumin synthesis is a hepatocyte function unrelated to MRP2
• D. Copper excretion is impaired in Wilson disease (ATP7B mutation), not Dubin-Johnson

Q84 — HNPCC: hPMS1, hPMS2, hMLH1 Gene Changes → Carcinogenesis Mechanism

• hMLH1, hMSH2, hMSH6, hPMS1, hPMS2

• Errors in microsatellite sequences accumulate → microsatellite instability (MSI)
• Mutations in growth-regulatory genes (e.g., TGF-β receptor, BAX) go uncorrected
• Progressive accumulation of mutations drives carcinogenesis

• B. Oncogene activation — the driver here is MMR deficiency, not primary oncogene activation
• C. Translocation of initiator/promoter genes — not the HNPCC mechanism
• D. RB gene deactivation — RB is relevant to osteosarcoma and retinoblastoma, not HNPCC

Q85 — Fulminant Viral Hepatitis: Which is NOT TRUE?

Note: Option B is also poorly worded (platelets vs. T-cells), but option D contains the most factually incorrect and testable error per Robbins — making D the best answer for "EXCEPT."

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q89 — Pituitary Mass and Erectile Dysfunction: Hormonal Mechanism

• B. Decreased FSH: FSH reduction alone does not primarily cause erectile dysfunction (testosterone, driven by LH, is the key androgen for erection); FSH governs spermatogenesis
• C. Increased GH: causes acromegaly — not primarily erectile dysfunction
• D. Decreased ACTH: causes secondary adrenal insufficiency — not erectile dysfunction as the primary manifestation

Q90 — Sudden Hemorrhage into Pituitary in a Pregnant Woman

Robbins: Sheehan syndrome presents with failure to lactate (first sign), followed by progressive loss of gonadotropins, TSH, ACTH, and GH function.

Q91 — Thyroid Tumor: Round/Polyhedral Cells + Amyloid Deposits

• Round to polyhedral cells (not follicular, not papillary)
• Pale pink amorphous amyloid deposits in stroma
• Anterior neck mass

MTC arises from parafollicular C cells (neural crest–derived), which secrete calcitonin. The amyloid in the stroma is derived from calcitonin precursor peptides. On Congo red stain, it shows apple-green birefringence.

Q92 — Schizophrenic Woman on Medications: Headache, Visual Disturbances, Irregular Menses, Breast Tenderness, Pituitary Enlargement

Robbins: Prolactinomas are the most common pituitary adenomas. They produce amenorrhea, galactorrhea (breast tenderness), infertility in women, and impotence in men.

• Corticotroph adenoma: causes Cushing disease (central obesity, striae, hypertension) — not this picture
• Gonadotroph adenoma: usually non-functional; presents as mass effect without hormonal excess
• Somatotroph adenoma: causes acromegaly (enlarged hands/feet, jaw changes, glucose intolerance)

Q93 — Deepening of Voice, Amenorrhea, Larger Shoe Size, Glucose Intolerance

1. IGF-1 level (elevated; better screening test than GH)
2. Oral glucose suppression test (GH fails to suppress)
3. MRI of the sella turcica — to localize the pituitary adenoma

• CT abdomen: not relevant; no abdominal source for GH excess
• Serum 21-hydroxylase: tests for congenital adrenal hyperplasia
• Serum androstenedione: tests for androgen excess (PCOS, CAH)

Q94 — Pheochromocytoma: Which Statement is NOT TRUE?

Robbins explicitly states: "There are no reliable histological criteria to distinguish benign from malignant pheochromocytoma." Neither vascular invasion, capsular invasion, nor nuclear pleomorphism can definitively predict malignancy. Malignancy is defined only by the presence of distant metastases (to sites where chromaffin tissue is normally absent: lymph nodes, liver, lung, bone).

Q95 — Pathogenesis of Congenital Anomalies: TRUE Statement

Valproic acid (antiepileptic) is a known teratogen that disrupts HOX gene expression. HOX proteins are transcription factors critical for the anterior-posterior patterning of the embryo, limb development, and vertebral segmentation. Valproic acid-induced HOX dysregulation underlies neural tube defects (spina bifida) and limb/vertebral anomalies.

Q96 — Why HDN (Rh Incompatibility) is Uncommon in First Pregnancy

During the first Rh+ pregnancy in an Rh− mother, fetal Rh+ RBCs cross the placenta (particularly at delivery), exposing the mother's immune system for the first time. This primary immune response generates IgM antibodies initially (which do not cross the placenta) followed eventually by IgG anti-Rh antibodies.

In a subsequent Rh+ pregnancy, the already-sensitized mother mounts a rapid secondary (anamnestic) IgG response. These IgG antibodies cross the placenta and destroy fetal RBCs → hemolytic disease.

• A. Type I hypersensitivity: HDN is Type II (IgG-mediated cytotoxic) hypersensitivity, not Type I (IgE-mediated)
• B. IgA dimers: the relevant antibody is IgG (monomer that crosses the placenta); IgA does not cross the placenta
• C. Cold antibodies crossing the placenta: cold antibodies are IgM (which cannot cross the placenta); the pathogenic antibody is IgG

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q87 — Iron Studies: Decreased Serum Iron, Increased TIBC, Decreased Ferritin, Decreased % Saturation

"A distinct pattern of results is noted in mild to moderate iron deficiency: low serum iron, high TIBC, low percent transferrin saturation, low serum ferritin."

Q88 — Splenomegaly, WBC 300,000/μL, Myeloid Predominance, Low LAP, Increased Basophils/Platelets

• Massive leukocytosis (WBC often >100,000/μL, can reach 300,000)
• All stages of myeloid maturation present (myeloblasts → promyelocytes → myelocytes → metamyelocytes → bands → neutrophils) with myelocyte predominance
• Basophilia and thrombocytosis — characteristic of CML
• Decreased leukocyte alkaline phosphatase (LAP) — a hallmark that distinguishes CML from leukemoid reaction (where LAP is high)
• Massive splenomegaly (extramedullary hematopoiesis)

• B. Mature B lymphocyte expansion in nodes → CLL
• C. Hypogammaglobulinemia → CLL or multiple myeloma
• D. Hair-like filamentous projections → Hairy Cell Leukemia

Q (Autopsy — Infant Renal Failure): Small Cystic Kidneys, Cartilage, Immature Mesenchyme

Disordered differentiation of metanephric tissue — the hallmark is the presence of primitive (immature) tubules and ducts surrounded by undifferentiated mesenchyme, with islands of cartilage (a tissue completely foreign to normal kidney). The kidneys are often cystic (multicystic dysplastic kidney) and small/shrunken.

• Medullary sponge kidney: dilated collecting ducts in medullary pyramids; not cystic cortex; no cartilage
• Prune belly syndrome: absent abdominal wall muscles + urinary tract dilation + cryptorchidism; no cartilage/mesenchyme
• Mixed mesenchymal tumor: a soft tissue tumor category, not a renal developmental entity

Q98 — Infant: Chloride/Bicarbonate Transport Defect, Thick Mucus, Positive Sweat Chloride Test

An autosomal recessive disease caused by mutations in the CFTR gene (cystic fibrosis transmembrane conductance regulator), which encodes a chloride channel. Defective CFTR impairs Cl⁻ transport (and secondarily HCO₃⁻ transport) at epithelial surfaces → thick, viscid mucus accumulates in the respiratory and GI tracts.

• Galactosemia: deficiency of galactose-1-phosphate uridylyltransferase → jaundice, liver failure, cataracts; no mucus/chloride abnormality
• Phenylketonuria: PAH deficiency → phenylalanine accumulation → intellectual disability, musty odor; no mucus/chloride
• Niemann-Pick: sphingomyelinase deficiency → sphingomyelin accumulation in macrophages; hepatosplenomegaly; no mucus

Q99 — Severe Erythroblastosis Fetalis: Findings EXCEPT

Tea-colored/dark brown urine indicates hemoglobinuria or myoglobinuria — seen in intravascular hemolysis (e.g., G6PD crisis, March hemoglobinuria, paroxysmal nocturnal hemoglobinuria), not in erythroblastosis fetalis, where hemolysis is extravascular (by macrophages). The bilirubin produced is unconjugated and is not excreted in urine (unconjugated bilirubin is water-insoluble and albumin-bound).

Q100 — Wilms Tumor Syndrome + Enlargement of Individual Organs

Summary Table

Robbins Textbook of Pathology — Referenced Answers

Q5 — The Repair Component of Healing Principally Involves:

1. Regeneration — replacement of injured cells by proliferation of surviving parenchymal cells of the same type (e.g., hepatocytes regrowing after partial hepatectomy)
2. Repair — when regeneration is insufficient or the tissue cannot regenerate, the defect is filled by supporting connective tissue (fibroplasia → collagen deposition → scar formation)

Robbins: "Repair, in contrast to regeneration, refers to the restoration of tissue architecture and function by replacement with connective tissue — ultimately leading to scar formation."

• A. Formation of new blood vessels (angiogenesis): this is a component of granulation tissue within repair, but it is not the principal/defining feature of repair itself
• B. Removal of cellular debris: this is the role of macrophages in acute inflammation (debridement), not repair
• D. Parenchymal cell regeneration: this describes regeneration, the other component of healing — distinct from repair

Q6 — Best Explanation of Chronic Inflammation

"Inflammation of prolonged duration (weeks to months or years) in which active inflammation, tissue destruction, and attempts at repair are proceeding simultaneously." The key driver is the persistence of the injurious stimulus — whether an infectious agent, autoimmune reaction, or foreign material — that prevents resolution.

• A. Inflammatory response after acute inflammation: this is an oversimplification; chronic inflammation can begin de novo without a preceding acute phase (e.g., autoimmune diseases, tuberculosis)
• B. Result of failure of acute response: while sometimes true, Robbins does not define chronic inflammation this way — many chronic inflammations (e.g., TB, RA) begin chronically from the outset
• C. Acquired immune response: the adaptive immune response participates in chronic inflammation, but it is not the definition of chronic inflammation itself

Q7 — Large Wound → Healed → Thick, Raised Scar That Stays Within Wound Boundaries

• A. Dehiscence: wound reopening/separation of sutured edges — the opposite of excessive healing
• C. Regeneration: restoration of normal tissue architecture without scar — clearly not the case here

Q8 — Appendicitis: Congested Appendix with Creamy Exudate on Serosa

Suppurative (purulent) inflammation is characterized by the production of pus — a creamy exudate composed of neutrophils, necrotic debris, and edema fluid. It typically results from pyogenic bacteria (e.g., E. coli, Staphylococcus). Acute appendicitis is the textbook example of suppurative inflammation.

Summary Table