Ch. 19 - Viral infections, helminths, and arthropods

Question 1

Verruca vulgaris

Answer 1

Exophytic papillomatous mass with compact eosinophilic hyperkeratosis. Koilocytes may be present.

Question 2

Myrmecia

Answer 2

Deep palmoplantar wart with anthill-like appearance. Associated with HPV-1.

Question 3

Verruca plana (flat wart)

Answer 3

Coarse basket-weave hyperkeratosis with hypergranulosis and “Bird’s eye” cells

Question 4

Epidermodysplasia verruciformis (EDV)

Answer 4

Widespread flat warts with foamy blue cytoplasm

Question 5

Condyloma acuminatum

Answer 5

Benign acanthoma on genital skin with vacuolated keratinocytes (true koilocytes are rare).

Question 6

Bowenoid papulosis

Answer 6

Discrete sessile genital lesion with full-thickness atypia. Associated with HPV-16.

Question 7

Heck’s disease

Answer 7

Focal oral hyperplasia. Hyperkeratosis with “round parakeratosis” and epithelial pallor. Associated with HPV-13 and -32.

Question 8

Verrucous cyst (cystic papilloma)

Answer 8

Cyst with wart-like lining. Resembles myrmecia on feet.

Question 9

Herpes simplex

Answer 9

Ballooning degeneration of keratinocytes with multinucleation and nuclear molding. Herpetic cytopathic effect. Mild leukocytoclastic vasculitis.

Question 10

Herpes zoster (VZV)

Answer 10

Ballooning degeneration of keratinocytes with multinucleation and cytopathic effect. Dramatic leukocytoclastic vasculitis.

Question 11

Chicken pox (VZV)

Answer 11

Ballooning degeneration of keratinocytes with multinucleation and cytopathic effect. Mild leukocytoclastic vasculitis.

Question 12

Verrucous VZV infection

Answer 12

Hyperkeratosis and papillomatosis with follicular herpetic cytopathic effect. Usually in HIV+ patients.

Question 13

Cytomegalovirus

Answer 13

Large endothelial cells with owl’s-eye nuclei.

Question 14

Smallpox (variola)

Answer 14

Epidermal necrosis with reticular degeneration, eosinophilic inclusions (Guarnieri bodies), and nuclear inclusions

Question 15

Monkey pox

Answer 15

Ballooning degeneration of basal keratinocytes with syncytia. Epidermal necrosis and spongiosis. Band-like and perivascular+periadnexal infiltrate.

Question 16

Molluscum contagiosum

Answer 16

Cup-shaped lesion with scalloped border. Contains Henderson-Paterson bodies.

Question 17

Orf and milker’s nodules

Answer 17

Epidermal necrosis with viral inclusion bodies. Long slender acanthosis?

Question 18

Gianotti-Crosti syndrome

Answer 18

Papular acrolocated syndrome with papillary dermal edema, crust, and perivascular lymphoid infiltrate. HPV/HBV.

Question 19

Hand, foot, and mouth syndrome

Answer 19

Oval vesicles with reticular and ballooning degeneration. Coxsackievirus.

Question 20

Schistosomiasis

(types?)

Answer 20

Ova with stippled contents and a mixed, often granulomatous inflammatory response.

• *Haematobium**: Thin wall, vertical spine
• *Mansoni**: Thick wall, lateral spine
• *Japonicum**: Thick wall, no spine

Question 21

Flatworms

Answer 21

Secretory tegument, rows of subtegumental cells. Calcareous bodies (waste), smooth muscle. No gut.

Question 22

Elephantiasis

Answer 22

Filarial roundworms within lymphatic vessels (inflammatory response causes lymphedema)

Question 23

Onchocercoma / microfilaria

Answer 23

Ball of male+female convoluted worms. Thin layer of striated muscle, corrugated cuticle. Large cephalic and caudal spaces.

Question 24

Dirofilariasis

Answer 24

Thick muscular layer interrupted by lateral cords. Internal chitinous ridge.

Question 25

Scabies

Answer 25

Mite, ova, or scybala in stratum cornea. Chitin scrolls/pigtails. Subepidermal bulla with eosinophils. Can mimic bullous pemphigoid or langerhans cell histiocytosis.

Question 26

Insect bite

Answer 26

Dense wedge-shaped perivascular lymphoid infiltrate with eosinophils and variable vascular damage / atypical lymphocytes.

Question 27

Insect sting

Answer 27

Highly variable. Often urticarial reaction followed by late stage fibrin/eosinophils/neutrophils.

Question 28

Tick, tick bite

Answer 28

Wedge-shaped inflammation and necrosis. Look for pigmented mouthparts, blood-filled gut.

Question 29

Myiasis

Answer 29

Fly larva with thick corrugated chitinous wall, pigmented setae, striated muscle, and gut.

Question 30

Tungiasis

Answer 30

Organism with red hollow tubules, gut, striated muscle in acral skin.

Question 31

Answer 31

Verruca vulgaris

Question 32

Answer 32

Myrmecia

Question 33

Answer 33

Verruca plana

Question 34

Answer 34

Condyloma acuminatum

Question 35

Answer 35

Bowenoid papulosis

Question 36

Answer 36

Verrucous cyst

Question 37

Answer 37

Herpes simplex

Question 38

Answer 38

Herpes zoster (shingles)

Question 39

Answer 39

Varicella (chicken pox)

Question 40

Answer 40

Verrucous zoster

Question 41

Answer 41

Cytomegalovirus

Question 42

Answer 42

Smallpox (variola)

Question 43

Answer 43

Monkeypox

Question 44

Answer 44

Molluscum contagiosum

Question 45

Answer 45

Orf nodule

Question 46

Answer 46

Gianotti-Crosti syndrome

Question 47

Answer 47

Hand, foot, and mouth disease

Question 48

Answer 48

Cutaneous schistosomiasis

Question 49

Answer 49

*Sparganum proliferum*

Question 50

Answer 50

Elephantiasis

Question 51

Answer 51

Onchocercoma

Question 52

Answer 52

*Onchocerca* microfilaria

Question 53

Answer 53

Subcutaneous dirofilariasis

Question 54

Answer 54

Scabies mite

Question 55

Answer 55

Insect bite

Question 56

Answer 56

Tick bite

Question 57

Answer 57

Myiasis

Question 58

Answer 58

Tungiasis