Dermatopathology Patterns and Direct Immunofluorescence Interpretation MCQs

Dermatology · 19 free questions with answers & explanations.

1. On direct immunofluorescence (DIF) of perilesional skin, intercellular IgG deposition in a 'fishnet/chicken-wire' pattern throughout the epidermis is MOST characteristic of:
2. In dermatitis herpetiformis (DH), the characteristic DIF finding is granular IgA in the dermal papillae. The antigen recognised by these IgA antibodies is:
3. Histology of a psoriatic plaque shows regular elongation of rete ridges, suprapapillary thinning, parakeratosis and collections of neutrophils within the stratum corneum. These neutrophilic collections are called:
4. On DIF of a patient with linear IgA bullous dermatosis, which pattern and immunoreactant is expected?
5. A skin biopsy from a patient with discoid lupus erythematosus (DLE) shows the 'lupus band' on DIF. This band consists of:
6. Skin biopsy of a patient with blistering disease shows: subepidermal blister, eosinophil-rich inflammatory infiltrate, and linear IgG + C3 along the basement membrane zone on DIF. Which diagnosis does this support?
7. A skin biopsy from a vesicular eruption over the elbows and buttocks shows neutrophilic microabscesses at the dermal papillary tips with subepidermal blistering. DIF reveals granular IgA deposits at dermal papillary tips. Which associated condition must be screened for?
8. In the lupus band test (DIF of non-lesional sun-protected skin), which immunoreactant pattern at the dermoepidermal junction is considered MOST specific for systemic lupus erythematosus?
9. Histopathology of a papulosquamous lesion shows hypergranulosis, 'saw-tooth' rete ridges, basal cell liquefaction, Civatte bodies, and colloid bodies with band-like lymphocytic infiltrate hugging the epidermis. What is the diagnosis?
10. In which blistering disease does indirect immunofluorescence (IIF) on rat oesophagus substrate give false-positive results, making monkey oesophagus the preferred substrate?
11. Direct immunofluorescence (DIF) of perilesional skin shows IgA deposits in a granular pattern at the dermal papillae tips. The patient has intensely pruritic papules and vesicles on elbows, knees, and buttocks. HLA-DQ2 is positive. Which enzyme is implicated in the autoimmune mechanism of this disease?
12. Skin biopsy from a patient with chronic prurigo-like lesions shows subepidermal blister with an infiltrate predominantly of eosinophils. DIF of perilesional skin shows linear IgG and C3 at the basement membrane zone (BMZ). Salt-split skin DIF localises the IgG to the epidermal side of the split. What is the diagnosis?
13. A skin biopsy shows basket-weave hyperkeratosis, hypergranulosis, and irregular acanthosis without parakeratosis. The rete ridges show a 'saw-tooth' appearance. There is a band-like lymphocytic infiltrate at the dermoepidermal junction with vacuolar change at the basal layer. Occasional civatte bodies (colloid bodies) are noted. DIF shows fibrinogen at the BMZ in a shaggy pattern. What is the diagnosis?
14. In pemphigus vulgaris, DIF of perilesional skin shows IgG and C3 in an intercellular (chicken-wire) pattern throughout the epidermis. The antibody titre correlates with disease activity. Using indirect immunofluorescence (IIF), the best substrate to detect these antibodies is:
15. A biopsy of a new plaque shows psoriasiform epidermal hyperplasia, but with small neutrophilic collections in the epidermis forming Kogoj spongiform pustules in addition to Munro microabscesses. Tortuous capillaries in dermal papillae are prominent. This pattern with spongiform pustules is most characteristic of which type of psoriasis?
16. A skin biopsy from a vesicle on the back shows linear IgG and C3 deposits along the basement membrane zone on direct immunofluorescence (DIF). Which layer does the blister form at on salt-split skin in bullous pemphigoid?
17. Direct immunofluorescence from lesional skin of dermatitis herpetiformis (DH) characteristically shows:
18. A biopsy from lesional skin shows interface dermatitis with a 'saw-tooth' pattern of epidermal hyperplasia, wedge-shaped hypergranulosis, and colloid bodies. The dermal infiltrate is band-like and 'hugs' the epidermis. This pattern is characteristic of:
19. A skin biopsy of a patch of erythema shows deep periadnexal and perivascular lymphocytic infiltrate extending into the reticular dermis, follicular plugging, basement membrane thickening on PAS stain, and mucin deposition. DIF shows granular IgM and C3 at the dermoepidermal junction. The diagnosis is: