Below is an overview of the GP histopathology course. Each of the topics will have a separate illustrated post. The GP Histopathology course is made up of Modules 1 thru 7B
View the video telecast for this topic (not active at present)
Here we will deal with the histopathology of the common tumours you will see in skin cancer practice. We will concentrate on those histological features that have a crucial impact in determining how you treat the lesion.
eg BCCs- Pathology relates to the treatments used
Superficial bcc V Nodular bcc V Infiltrating or Morphoeic
Thickness - penetration of creams eg Aldara and red light in PDT
Significance of Infiltrating BCC with these modalities
Basisquamous BCC
BCC with perineural spread
BCC in vessels- very rare
eg SCCs- SCC in situ- confined to epidermis
Compare and contrast clonal Seb K V SCC in situ
Invasive SCC can be well differentiated through to poorly differentiated -Significance for treatment?
SCC with perineural spread
Spindle cell tumours- Need for special stains to sort them out
Pigmented Lesions
Solar lentigo V Lentigo maligna V flat dark Seb K
Clinical V dermatoscopic V histology V Confocal microscopy
Different types of melanoma
Dysplastic nevus V Melanoma
Important clinical features- Age, other dysplastic nevi, dermatoscopic view
When to ask for further cuts
Importance of the type of biopsy used to sample the pigmented lesion.
Why partial punch biopsies are a potential death trap.
What cytological features make a melanocyte histologically atypical?
Nevi
Types of nevi- junctional, compound, dermal, congenital, dysplastic, Spitz, combined , blue
The difficulties with Spitz nevi
Pigmented non melanocytic tumours
Pigmented BCC
Pigmented SCC in situ Bowen's disease
Other Tumours- Benign and Malignant
Malignant
Merkel cell- histology, special stains, wide excision, refer, radiotherapy
AFX- Atypical fibroxanthoma, like a poorly differentiated SCC,
MFH- Malignant fibrous histiocytoma- goes deep, wide excision 10 mms.
DFX- dermtofibrosarcoma protuberans- very wide excision 3-5 cms- refer.
Recurrent SCCs- refer early, wide excision, often perineural or lymphatic spread.
Angiosarcoma- looks like a big bruise
T and B cell lymphomas
Benign
Often face- Adnexal tumours
Eccrine glands- syringomas, hidradenomas
Hair follicles- Trichoepitheliomas, desmoplastic variant, Cylindromas
Sebaceous glands- Seb adenoma, Sebaceous carcinoma
Vascular- Pyogenic granuloma, Kaposi's sarcoma
Epidermal nevi- Sebaceous nevi- Syringocystadenoma papilliferum, Trichoblastoma, form fruste BCC
Clear cell acanthoma
LPLK
Porokeratosis
Actinic keratosis
Viral wart
Medical Conditions confused with Skin Cancer
Prurigo nodules- pseudoepitheliomatous hyperplasia
Discoid lupus erythematosus
Deep fungal and Atypical mycobacterial infections
Early T cell lymphoma
Angiolymphoid hyperplasia
Granuloma faciale
Lymphocytoma cutis
Post scabetic nodule
Persistent insect bite reaction
Sweet's syndrome
Erythema elevatum diutinum
Tumoral calcinosis
granuloma annulare and NLD
Sarcoidosis
Xanthomas
