LATEST PATHOLOGY - DERMATOPATHOLOGY
CERTIFICATION EXAM OFFERED BY
AMERICAN BOARD OF PATHOLOGY (ABMS) |
COMPLETE EXAM Q&A WITH RATIONALES
1. A 45-year-old man presents with a slowly growing,
pink, dome-shaped nodule on the face. Biopsy shows
a dermal proliferation of basaloid cells with
peripheral palisading, retraction artifact, and
mucinous stroma. There is no connection to the
overlying epidermis. What is the most likely
diagnosis?
A) Basal cell carcinoma, nodular type
B) Trichoepithelioma
C) Desmoplastic trichoepithelioma
D) Merkel cell carcinoma
Correct answer: A
Rationale: Nodular basal cell carcinoma shows
dermal islands of basaloid cells with peripheral
palisading, retraction (clefting) artifact, and
mucinous stroma. Lack of epidermal connection
favors BCC over trichoepithelioma (B).
,2. A 32-year-old woman presents with a pruritic,
annular, erythematous plaque on the trunk with a
trailing scale. Biopsy shows a psoriasiform dermatitis
with a mound of parakeratosis containing neutrophils
(Munro microabscesses). What is the most likely
diagnosis?
A) Pityriasis rosea
B) Psoriasis vulgaris
C) Eczema (spongiotic dermatitis)
D) Lichen planus
Correct answer: B
Rationale: Psoriasis vulgaris shows regular
acanthosis, parakeratosis (usually confluent),
neutrophils in the stratum corneum (Munro
microabscesses), and thinning of the suprapapillary
plates (F = Figure 2). Auspitz sign correlates.
3. A 55-year-old man presents with a
hyperpigmented, irregular macule on the sun-
exposed forearm. Biopsy shows atypical melanocytes
as single cells at the dermoepidermal junction and
nests that vary in size and shape (shoulder
phenomenon). Pagetoid spread is absent. What is the
most likely diagnosis?
A) Lentigo maligna (melanoma in situ)
,B) Dysplastic nevus
C) Superficial spreading melanoma
D) Solar lentigo
Correct answer: A
Rationale: Lentigo maligna (Hutchinson melanotic
freckle) occurs on sun-damaged skin of older adults.
Histology: atypical melanocytes along the basal layer
with confluence, sun elastosis, and variable pagetoid
spread (usually minimal). Solar lentigo (D) has no
atypia.
4. A 25-year-old man presents with multiple
violaceous, polygonal, flat-topped papules on the
wrists. Biopsy shows a band-like lymphocytic
infiltrate at the dermoepidermal junction, vacuolar
alteration of the basal layer, and wedge-shaped
hypergranulosis. What is the most likely diagnosis?
A) Lichen planus
B) Lupus erythematosus
C) Lichen simplex chronicus
D) Graft-versus-host disease
Correct answer: A
Rationale: Lichen planus shows a dense lymphocytic
band (lichenoid infiltrate), vacuolar interface change,
, "saw-tooth" rete ridges, wedge-shaped
hypergranulosis, and Civatte bodies (apoptotic
keratinocytes). Predilection for flexor wrists and oral
mucosa.
5. A 68-year-old man presents with an ulcerated,
bleeding nodule on the scalp. Biopsy shows a dermal
proliferation of atypical epithelioid cells with
pleomorphic nuclei, prominent nucleoli, and
numerous mitoses. The cells are positive for
cytokeratin, EMA, and BerEP4. They are negative for
S-100 and Melan-A. What is the most likely diagnosis?
A) Basal cell carcinoma
B) Squamous cell carcinoma
C) Merkel cell carcinoma
D) Melanoma
Correct answer: C
Rationale: Merkel cell carcinoma (primary cutaneous
neuroendocrine carcinoma) shows small blue cells
with finely granular chromatin, nuclear molding, and
high mitotic rate. It is CK20 positive (dot-like
perinuclear) and neuroendocrine marker positive
(synaptophysin, chromogranin). Negative for S-100
and Melan-A.
CERTIFICATION EXAM OFFERED BY
AMERICAN BOARD OF PATHOLOGY (ABMS) |
COMPLETE EXAM Q&A WITH RATIONALES
1. A 45-year-old man presents with a slowly growing,
pink, dome-shaped nodule on the face. Biopsy shows
a dermal proliferation of basaloid cells with
peripheral palisading, retraction artifact, and
mucinous stroma. There is no connection to the
overlying epidermis. What is the most likely
diagnosis?
A) Basal cell carcinoma, nodular type
B) Trichoepithelioma
C) Desmoplastic trichoepithelioma
D) Merkel cell carcinoma
Correct answer: A
Rationale: Nodular basal cell carcinoma shows
dermal islands of basaloid cells with peripheral
palisading, retraction (clefting) artifact, and
mucinous stroma. Lack of epidermal connection
favors BCC over trichoepithelioma (B).
,2. A 32-year-old woman presents with a pruritic,
annular, erythematous plaque on the trunk with a
trailing scale. Biopsy shows a psoriasiform dermatitis
with a mound of parakeratosis containing neutrophils
(Munro microabscesses). What is the most likely
diagnosis?
A) Pityriasis rosea
B) Psoriasis vulgaris
C) Eczema (spongiotic dermatitis)
D) Lichen planus
Correct answer: B
Rationale: Psoriasis vulgaris shows regular
acanthosis, parakeratosis (usually confluent),
neutrophils in the stratum corneum (Munro
microabscesses), and thinning of the suprapapillary
plates (F = Figure 2). Auspitz sign correlates.
3. A 55-year-old man presents with a
hyperpigmented, irregular macule on the sun-
exposed forearm. Biopsy shows atypical melanocytes
as single cells at the dermoepidermal junction and
nests that vary in size and shape (shoulder
phenomenon). Pagetoid spread is absent. What is the
most likely diagnosis?
A) Lentigo maligna (melanoma in situ)
,B) Dysplastic nevus
C) Superficial spreading melanoma
D) Solar lentigo
Correct answer: A
Rationale: Lentigo maligna (Hutchinson melanotic
freckle) occurs on sun-damaged skin of older adults.
Histology: atypical melanocytes along the basal layer
with confluence, sun elastosis, and variable pagetoid
spread (usually minimal). Solar lentigo (D) has no
atypia.
4. A 25-year-old man presents with multiple
violaceous, polygonal, flat-topped papules on the
wrists. Biopsy shows a band-like lymphocytic
infiltrate at the dermoepidermal junction, vacuolar
alteration of the basal layer, and wedge-shaped
hypergranulosis. What is the most likely diagnosis?
A) Lichen planus
B) Lupus erythematosus
C) Lichen simplex chronicus
D) Graft-versus-host disease
Correct answer: A
Rationale: Lichen planus shows a dense lymphocytic
band (lichenoid infiltrate), vacuolar interface change,
, "saw-tooth" rete ridges, wedge-shaped
hypergranulosis, and Civatte bodies (apoptotic
keratinocytes). Predilection for flexor wrists and oral
mucosa.
5. A 68-year-old man presents with an ulcerated,
bleeding nodule on the scalp. Biopsy shows a dermal
proliferation of atypical epithelioid cells with
pleomorphic nuclei, prominent nucleoli, and
numerous mitoses. The cells are positive for
cytokeratin, EMA, and BerEP4. They are negative for
S-100 and Melan-A. What is the most likely diagnosis?
A) Basal cell carcinoma
B) Squamous cell carcinoma
C) Merkel cell carcinoma
D) Melanoma
Correct answer: C
Rationale: Merkel cell carcinoma (primary cutaneous
neuroendocrine carcinoma) shows small blue cells
with finely granular chromatin, nuclear molding, and
high mitotic rate. It is CK20 positive (dot-like
perinuclear) and neuroendocrine marker positive
(synaptophysin, chromogranin). Negative for S-100
and Melan-A.
