CLASSIC LAB/FINDINGS III

Question 1

Sheets of medium-sized lymphoid cells with scattered
pale, tingible body–laden macrophages (“starry sky”
histology)

Answer 1

Burkitt lymphoma (t[8:14] c-myc activation, associated
with EBV; “starry sky” made up of malignant cells)

Question 2

Lytic (“punched-out”) bone lesions on x-ray

Answer 2

Multiple myeloma

Question 3

Monoclonal antibody spike

Answer 3

Multiple myeloma (usually IgG or IgA)

Monoclonal gammopathy of undetermined significance (MGUS consequence of aging)

Waldenström (M protein = IgM) macroglobulinemia

Primary amyloidosis

Question 4

Stacks of RBCs

Answer 4

Rouleaux formation (high ESR, multiple myeloma)

Question 5

Azurophilic peroxidase ⊕ granular inclusions in

granulocytes and myeloblasts

Answer 5

Auer rods (AML, especially the promyelocytic [M3] type)

Question 6

WBCs that look “smudged”

Answer 6

CLL (almost always B cell)

Question 7

“Tennis racket”-shaped cytoplasmic organelles (EM) in

Langerhans cells

Answer 7

Birbeck granules (Langerhans cell histiocytosis)

Question 8

“Brown” tumor of bone

Answer 8

Hyperparathyroidism or osteitis fibrosa cystica (deposited

hemosiderin from hemorrhage gives brown color)

Question 9

“Soap bubble” in femur or tibia on x-ray

Answer 9

Giant cell tumor of bone (generally benign) 464

Question 10

Raised periosteum (creating a “Codman triangle”)

Answer 10

Aggressive bone lesion (eg, osteosarcoma, Ewing sarcoma, osteomyelitis)

Question 11

“Onion skin” periosteal reaction

Answer 11

Ewing sarcoma (malignant small blue cell tumor)

Question 12

Anti-IgG antibodies

Answer 12

Rheumatoid arthritis (systemic inflammation, joint pannus, boutonniere and swan neck deformities)

Question 13

Rhomboid crystals, ⊕ birefringent

Answer 13

Pseudogout (calcium pyrophosphate dihydrate crystals)

Question 14

Needle-shaped, ⊝ birefringent crystals

Answer 14

Gout (monosodium urate crystals)

Question 15

increase uric acid levels

Answer 15

Gout, Lesch-Nyhan syndrome, tumor lysis syndrome, loop and thiazide diuretics

Question 16

“Bamboo spine” on x-ray

Answer 16

Ankylosing spondylitis (chronic inflammatory arthritis: HLA-B27)

Question 17

Antinuclear antibodies (ANAs: anti-Smith and anti-
dsDNA)

Answer 17

SLE (type III hypersensitivity)

Question 18

Anti-histone antibodies

Answer 18

Drug-induced SLE (eg, hydralazine, isoniazid, phenytoin, procainamide)

Question 19

Anti-topoisomerase antibodies

Answer 19

Diffuse scleroderma

Question 20

Keratin pearls on a skin biopsy

Answer 20

Squamous cell carcinoma

Question 21

Bloody or yellow tap on lumbar puncture

Answer 21

Xanthochromia (due to subarachnoid hemorrhage)

Question 22

Eosinophilic cytoplasmic inclusion in neuron

Answer 22

Lewy body (Parkinson disease and Lewy body dementia)

Question 23

Extracellular amyloid deposition in gray matter of brain

Answer 23

Senile plaques (Alzheimer disease)

Question 24

Depigmentation of neurons in substantia nigra

Answer 24

Parkinson disease (basal ganglia disorder: rigidity, resting tremor, bradykinesia)

Question 25

Protein aggregates in neurons from hyperphosphorylation

of tau protein

Answer 25

Neurofibrillary tangles (Alzheimer disease) and Pick
bodies (Pick disease)

Question 26

Silver-staining spherical aggregation of tau proteins in

neurons

Answer 26

Pick bodies (Pick disease: progressive dementia, changes in personality)