Skin Flashcards
Skin Special Stains
Bugs: PAS, GMS, Gram, Warthin Starry, ZN, Fite
Pigment: PERLS, Fontana Masson
Structural Components: EVG (vessels, perforating), Masson Trichrome (fibrosis, collagen deposition, perforating dx)
Other PAS - BM, Hales intradermal mucin
Clear Cell Tumours in Skin
SCC with clear cell changes
Clear cell acanthoma
Melanoma with balloon cell changes
Clear cell sarcoma
Hidradenoma
Sebaceous neoplasms
PEComas
BCC with clear cells
Metastases - ccRCC
DDx Busy Dermis
NON NEOPLASTIC:
Inflammation esp. histiocyte rich eg. fungi, leprosy
GA, especially interstitial GA
NEOPLASTIC:
Dermatofibroma
Naevi esp. congenital and blue
Neurofibroma
Myeloid sarcoma
Role of DIFL in Skin Disease
DIFL is used to assist in the diagnosis of immune mediated skin disorders in conjunction with the H&E and the clinical features (including serology and skin auto-antibodies).
DIFL is based on attaching a flurophore to an antibody raised against the antigen of interest.
Requires a separate specimen from perilesional skin, sent in Michels medium and kept refrigerated. Cut on crytostat and stained with antibodies against IgG, IgM, IgA, fibrin and C3.
Synoptic Report for Melanoma
Specimen type and site of tumour
Histologic subtype of Melanoma
- superficial spreading, lentigo maligna, nodular, nevoid, acral, spitzoid
Breslow thickness
Anatomic (Clark) Level
Ulceration
Satellite nodules (macroscopic and microscopic)
Mitotic rate (per square millimetre)
Lymphovascular space invasion
Neurotropism
TIL’s (brisk versus non-brisk)
Tumour Regression
Margin status to in situ and invasive
Lymph nodes (sentinel and / or regional)
Distant metastases
Biomarkers: BRAF, NRAS, C-KIT
How Do You Measure Breslow Thickness?
With a calibrate ocular micrometer (graticule) at right angles to the adjacent normal skin
Upper point of reference is the upper edge of the granular layer of the epidermis of the overlying skin; or if ulcerated the base of the ulcer
Lower reference point is the deepest point of tumour invasion i.e. the leading edge of a single mass or isolated group of cells deep to the main mass
How do you define Neurotropsim in Melanoma?
- Presence of melanoma cells abutting / encircling nerve sheaths or within nerves
- Sometimes the tumour itself may form neuroid structures “neural transformation”, also considered neurotropism
What are the Anatomic (Clark) levels?
I. Intraepidermal tumour only (i.e. in situ)
II. Tumour present in, but does not expand, the papillary dermis
III. Tumour fills and expands papillary dermis
IV. Tumour invades into reticular derms
V. Tumour invades subcutis
How do you define horizontal and vertical growth phases in melanoma?
In horizontal phase melanoma cells spread out along the DEJ and occasionally papillary dermis radially.
In vertical growth phase the epidermal nests become larger than the epidermal nests and dermal mitoses appear.
Name some Dermatologic Emergencies
Emergencies:
Angioinvasive fungal infection
Stevens -Johnsom / TEN
Acute GVHD
Urgencies:
Calciphylaxis
Bullous pemphigoid
Sweet syndrome (febrile neutrophilic dermatosis)
Pyoderma gangrenosum
Cutaneous LCV
DIFL staining pattern in Intraepidermal Bullous Disorders
Intraepidermal blistering dermatoses = SSSS, bullous impetigo, pemphigus
All types of Pemphigus (except see below)
IgG, lace like, spinous layer
IgA Pemphigus
IgA, lace like, spinous layer
Paraneoplastic Pemphigus
IgG, lace like, spinous layer
C3, IgG, linear EBMZ
C3, IgG, granular EBMZ
DIFL staining pattern in Subepidermal Bullous Dermatoses
Sub epidermal bullous dermatoses = pemphigoid, EBA, DH, PCT etc.
Bullous pemphigoid & Cicatricial pemphigoid
C3 >> IgG, linear EBMZ
Immune deposits on the roof in salt-split skin
Herpes Gestationis
C3, linear EBMZ
Epidermolysis bullosa acquisita
IgG >> C3, linear EBMZ
Immune deposits on the floor of blister on salt-split skin
Bullous SLE
Linear or granular C3 and IgG, EBMZ
Dermatitis herpetiformis
Granular IgA, EBMZ
Linear IgA disease
Linear, IgA, EBMZ
DDx of Subcorneal Neutrophilic Dermatoses
Bugs: Fungus, Bullous impetigo
Drugs: AGEP
Autoimmune: Pustular psoriasis, Pemphigus foliaceus, Dermatitis herpetiformis
DDx Subcorneal Split
Bullous impetigo
Pemphigus foliaceus
Staph Scalded Skin Syndrome
DDx Intraepidermal / Suprabasilar Split
Pemphigus vulgaris
Paraneoplastic pemphigus
Spongiotic dermatitis
Infection e.g. herpes, hand, foot and mouth
Acantholytic dyskeratosis: Dariers, Hailey-Hailey, Grovers
