Dermatopathology Flashcards
What are the reasons to take a skin biopsy?
- Possible skin cancer
- Inflammatory skin condition
- Possible drug reaction
- Dermatological emergency
- Infection or infestation
In histology what do grey structures in the dermis represent?
Sun damage
What are the layers of the epidermis?
- Stratum corneum
- Stratum granulosum
- Stratum spinosum
- Stratum basalis
Describe the appearance of keratinocytes
Squamous epithelial cells
Describe the appearance of melanocytes
Clearer cells along the basal epidermis
Why is skin pathology important?
- For accurate Diagnosis of the skin condition
- For treatment of a suspicious lesion
- Prognosis and staging of tumours
- Further patient management
What are the malignant epithelial tumours?
- Basal cell carcinoma
- Squamous cell carcinoma
- Merkel cell carcinoma
- Extramammary pagets disease
- Carcinosarcoma
What are the 4 malignant skin cancer types?
- Malignant epithelial tumours
- Malignant melanoma
- Cutaneous lymphoma
- Sarcoma
What are the risk factors for developing a basal carcinoma?
- UV exposure/ sun damage
- Age
- Immune compromise and specific genodermatoses
- Arsenic exposure
- Coal tar derivatives
- Irradiation
- Scars
- Sinuses
- Ulcers
Where do the majority of basal cell carcinomas occur?
On the head and neck in unexposed areas
Explain the histopathology of a basal cell carcinoma
- Originate from follicular bulge stem cells and basaloid epithelia of follicular projections of anagen hair buds
- Dual population of fibrous stroma and islands of basaloid cells
- Peripheral palisading and haphazard arrangement of cells in centre of islands
- Numerous mitoses and apoptotic bodies
Which of the basal cell carcinomas has the least risk of recurrence?
Nodular
Which basal cell carcinoma has a higher risk of recurrence?
Infiltrative
What is the definition of a squamous cell carcinoma?
- Malignant neoplasm of the epidermal keratinocytes
* Component cells show various squamous differentiation
Describe the histology of squamous cell carcinoma
- Nests or islands of squamous cells arising from the epidermis and extending into the dermis or beyond
- Variable keratinisation depending upon differentiation of the tumour (more differentiation= more keratin)
TX
Tumour cannot be assessed
T0
No evidence of primary tumour
Tis
Carcinoma in situ
T1
Tumour
T4a
Tumour with gross cortical/marrow invasion
T4b
Tumour with axial skeleton/skull base/foraminal invasion
What is breslow thickness?
Measured from the most superficial aspect of granular cell layer (or from the base of ulcer) to deepest point of invasion
What are the tumour related prognostic factors of a malignant melanoma
- Tumour thickness
- Mitotic rate
- Ulceration
- Extent of metastatic disease
What are the non tumour related prognostic factors of malignant melanoma
- Lymphatic invasion
- Perineural invasion
- Family history
- Sun exposure, tanning beds
- molecular mutational gene expression, immunogenetics
