Derm In Review - Dermatopathology Flashcards
What do eccrine glands stain positive for?
S-100 and CEA
What is giemsa stain used for?
Stains mast cell granules (heparin in the granules) and Leishmaniasis
The predominant location of the cleft in cicatricial pemphigoid is what?
BMZ
The histologic finding of “shoulder parakaratosis”, parakeratosis with prediliection for the follicular ostia, is characteristic of pityriasis rubra pilaris as well as what other skin condition?
Seborrheic dermatitis
Where is the inflammation in each of the following?
- Alopecia areata
- Discoid lupus
- Lichen planopilaris
- Alopecia areata → hair bulb
- Discoid lupus → isthmus
- Lichen planopilaris → infundibulum
Which marker helps to differentiate extranodal NK-T cell lymphoma from cutaneous gamma delta lymphoma?
EBV status
Both cutaneous gamma delta lymphoma and extranodal NK-T cell lymphoma are CD56+. However, only extranodal NK-T cell lymphoma is EBV + while cutaneous gamma delta lymphoma is EBV negative. Both these lymphomas have a 5-year survival rate that approaches 0%.
This tumor is vimentin+ and cytokeratin+.
Epithelioid sarcoma
Characteristic immunohistochemistry of epithelioid sarcoma is vimentin and cytokeratin positivity.
The pigment deposits in ochronosis are accentuated with what two stains?
Cresyl violet and methylene blue stains pigment deposits black
A patient presents with recurrent crops of papules that ulcerate and then spontaneously heal. What immunohistochemical stain would be helpful in making the diagnosis?
CD30
Lymphomatoid papulosis
The PDGF gene has been shown to be translocated into the collagen I gene in what skin lesion?
DFSP
Guarnieri bodies can be found associated with which of the following viral infections?
Variola (smallpox)
Guarnieri bodies are eosinophilic intracytoplasmic inclusions associated with variola infection (smallpox), however they can also be seen in infections with other pox viridae including vaccinia, cowpox, and parapox. These inclusions represent aggregates of viral particles.
The predominant location of the cleft in acropustulosis of infancy is where?
Subcorneal/granular layer
Mantle cell lymphoma is characteristically positive for what?
Bcl-1 (cyclin D1)
Methyl-green pyronin stains RNA what color? What about DNA?
RNA is stained pink.
DNA is stained green.
You diagnose a patient with multiple epidermal tumors that on histopathology shows a fibrous pink orb with epithelial strands coming through the follicular center. The patient most likely has a mutation in which gene?
FLCN
This describes a fibrofolliculoma, a tumor seen in Birt-Hogg-Dubé syndrome. This is an autosomally dominant syndrome due to a mutation in FLCN - folliculin (Choice 3), a tumor suppressor gene. Patients show these skin lesions and have an increased risk for renal cell carcinoma, spontaneous pneumothoraces, pulmonary cysts, and medullary carcinoma of the thyroid.
On histology this disease has mucin deposition within the external root sheath and sebaceous gland. The mucin distends into the intracellular spaces within follicular epithelium forming cystic cavities. The following stains will be positive EXCEPT for which one of the following:
- CD4
- CD9
- CD7
- CD8
- CD3
CD9
Follicular mucinosis
Mulberry cells contain increased number of what cellular organelle?
Mitochondria
Mulberry cells are seen in hibernoma.
Metastatic renal cell carcinoma stains positive for what? (3)
Epithelioid membrane antigen, carcinoembryonic antigen, CD-10, renal cell carcinoma marker are markers used to identify skin metastases of renal cell carcinoma.
What two stains does cellular neurothekeoma stains with?
S-100a6 and PGP-9.5
The differential for parasitized macrophages can be remembered using the mnemonic His GIRL Penelope:
His-Histoplasmosis
GI-Granuloma inguinale (aka Donovanosis)
R- Rhinoscleroma (not to be confused with Rhinosporidiosis)
L- Leishmaniasis
Penelope- Penicilliosis
Which type of PRP is most common in children?
Type IV
In PRP, type 4 is circumscribed juvenile version, which is the most common form in kids.
Type 1 is classic adult. Type 2 is atyical, chronic adult. Type 3 is classic juvenile, type 5 is atypical juvenile. A sixth form associated with HIV has been described as well.
What is the treatment of choice for a MCC without LAD?
WLE with SNLB
The preferred treatment for a tumor on the trunk without clinically apparent lymphadenopathy is wide local excision (1-3 cm margins) and sentinel lymph node biopsy. If the lymph node biopsy is positive, then the patient will likely require radiation therapy. For lesions >2cm, some clinicians will not perform a sentinel lymph node biopsy since radiation therapy is indicated regardless, given the high risk of lymph node metastasis.
Grenz zone differential
Lepromatous leprosy, cutaneous B cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, acute myelomonocytic leukemia, leiomyosarcoma, and Botryoid rhabdomyosarcoma.
