Histopath Flashcards
Define Cavernous Angiomas
Well defined malformative lesions composed of closely packed vessels with no parenchyma interposed between vascular spaces.
Note: it’s similar to an arteriovenous malformation but there’s no brain substance wrapped up amongst the vessels.
Note: these tend to bleed at a lower pressure than intraparenchymal haemorrhages and tend to cause recurrent small bleeds.
Note: shows target sign on MRI
Describe the Braak stages of Alzheimer’s disease.
Stage 1: Tau pathology in transentorhinal cortex
Stage 2: posterior hippocampus
Stage 3: immunostaining visible to the eye, affects substantia nigra
Stage 4: superior temporal gyrus
Stage 5: peristriate cortex
Stage 6: striate cortex
Note: Clinically symptoms tend to arise in stages 3 or 4
What is Multiple System Atrophy?
It’s an alpha-synucleinopathy similar to Parkinson’s Disease which attacks glial cells.
It presents similarly to Parkinson’s disease.
It mainly affects the cerebellum so the patients are more likely to present with falls.
What are the histological features of Pick’s disease?
Marked gliosis and neuronal loss.
Balloon neurones
Tau positive Pick bodies
Note: Mutations in Tau are associated with a Fronto-Temporal Dementia phenotype that is often associated with Parkinson’s disease
Note: There are 17 autosomal dominant syndromes resulting from mutations of Tau
Describe how the types of tau present in Alzheimer’s is different from that present in Corticobasal Degeneration (CBD), Progressive Supranuclear Palsy(PSP) and Pick’s Disease.
Alzheimer’s- when the tau is put through Western Blot, it shows up as 3 dense bands. If this is dephosphorylated it shows all 6 isoforms of tau.
CBD, PSP- when the tau is put through Western Blot it shows up as 2 dense bands, if these are dephosphorylated it shows up as only 4R tau isoform- so CBD and PSP are ‘4R tauopathies’
Pick’s disease- 3R tauopathy
Outline the pathophysiology of ARDS.
Exudative phase- the lungs become congestive and leaky
Hyaline membranes- formed when serum protein that is leaked out of the vessels end up lining the alveoli
Organising phase- organisation of the exudates to form granulation tissue sitting within the alveolar spaces
What are the histopathological stages of Lobar Pneumonia
Stage 1: congestion (hyperaemia and intra-alveolar fluid)
Stage 2: red hepatisation (hyperaemia and intra-alveolar neutrophils)
Stage 3: grey hepatisation (intra-alveolar connective tissue)
Stage 4: resolution (restoration of normal tissue architecture)
Which molecular changes are important to test for in adenocarcinoma?
EGFR (responder or resistance)
ALK (translocation)
Ros1 (translocation)
Note: it is important to correctly identify the type of lung cancer due to treatment implications e.g. bevacizumab can cause fatal pulmonary haemorrhage in squamous cell carcinoma
List some tumour like conditions of the bone
Fibrous dysplasia
Metaphyseal fibrous cortical defect/non-ossifying fibroma
Reparative Giant cell granuloma
Ossifying fibroma
Simple bone cyst
What is Fibrous Dysplasia
Condition where fibrous tissue develops in place of normal bone tissue
Can happen in any bones but most often in ribs and proximal femur
Most common in people less than 30 yrs
Causes soap bubble osteolysis appearance on X-ray
Note: giant cell tumours also cause soap bubble osteolysis on X-ray, but this most tends to happen in the bones around the knees
What is an enchondroma and in which bones does it occur?
A Cartilaginous proliferation within the bone.
Most tend to happen in the hands
Can cause pathological fractures
May show popcorn calcifications on X-Ray
Associated with Ollier's and Mafucci Syndromes
Which cancers in children tend to spread to bones?
Neuroblastoma
Wilm's Tumour
Osteosarcoma
Ewing's sarcoma
Rhabdomyosarcoma
List the Histological subtypes of chondrosarcoma...
Conventional (Myxoid or Hyaline)
Clear Cell (Low Grade)
Dedifferentiated (High Grade)
Mesenchymal
Note: Myxoid= composed of clear mucoid substance
Describe the histological appearance of the following breast cancers:
A) Invasive Ductal Carcinoma
B) Invasive Lobular Carcinoma
C) Invasive Tubular Carcinoma
D) Invasive Mucinous Carcinoma
A) Invasive Ductal Carcinoma
Cells are pleomorphic with abnormally large nuclei
B) Invasive Lobular Carcinoma
Cells in linear arrangement with monomorphic nuclei
Note: cords of cancer cells in linear arrangement are referred to as being an ‘Indian File Pattern’
C) Invasive Tubular Carcinoma
Elongated tubules of cancer cells invading the stroma
D) Invasive Mucinous Carcinoma
Lots of ‘empty’ spaces, filled with mucin.
Outline the coding for biopsies of suspicious breast lumps
B1) Normal Breast tissue
B2) Abnormal benign tissue
B3) Abnormal tissue of uncertain malignant potential
B4) Tissue suspicious of malignancy
B5) Malignant tissue (a= DCIS; b= invasive carcinoma)
What’s the basis for papillary thyroid cancer diagnosis
Nuclear Features:
1) Optically clear nuclei
2) Intranuclear inclusions- “Orphan Annie eyes”
May have Psammoma bodies- little foci of calcification
Usually non-functional
On histology have papillary structure- central connective tissue stalk surrounded by epithelium
How can you measure anti-dsDNA
1) You can use ELISA
2) You can culture a sample with Crithidia Luciliae (prototozoan kinetoplast)
It has a large mitochondrion with a large kinetoplast (network of anti-dsDNA)
If anti-dsDNA is present in the sample they will bind to the protozoan dsDNA
Describe skin histology appearance in SLE
1) Lymphocytic infiltration of the Dermis
2) Vacuolisation (dissolution of cells) of the Basal Epidermis
3) Extravasation of blood causes a rash
4) Immunofluorescence shows immune complex deposition at the Dermis-Epidermis junction.
What is Polyarteritis Nodosa?
What are its main features?
1) A Necrotising arteriosclerosis which is focal and sharply demarcated
2) It heals by Fibrosis and mainly affects the Renal and Mesenteric vessels
3) May present with Gut Ischaemia or Renal Impairment
4) It produces a Rosary Beads appearance on Angiography due to multiple Aneurysms
5) Associated with Hepatitis B
What are the 2 types of HPV infection? Describe their features.
[1] Latent (non-productive)
1) HPV DNA continues to reside within Basal cells
2) Infectious virions are not produced
3) Replication of viral DNA is coupled to replication of epithelial cells
4) This means that complete viral particles are not produced
5) Cellular effects of HPV are not seen
[2] Productive
1) Viral DNA replication occurs independently of host cell DNA synthesis
2) Large amounts of Viral DNA and infectious virions are produced
3 Characteristic cytological and histological features are seen- halo around the nucleus (Koilocytes)
Which Genetic Mutations are associated with the two types of Type 2 Endometrial Carcinoma?
[1] Endometrial Serous Carcinoma
1) P53 (90%)
2) PK13CA (15%) Her2 amplification
[2] Clear Cell Carcinoma
1) PTEN
2) CTNNB1
3) Her2 amplification
Describe how complete and partial moles form
[1] Complete Moles
1) Occurs when you get an empty egg fertilised by a sperm
2) Reduplication of 23X from sperm results in a Homozygous Diploid 46XX genome
3) Can also occur due to fertilisation of an empty egg by 2 sperm with 2 independent sets of 23X or 23Y
[2] Partial Moles
1) A normal ovum containing 23X gets fertilised by 2 sperm leading to the presence of 3 sets of chromosomes (2 paternal and 1 maternal)
2) Dispermia/diandry
3 Overdose of male chromosomes drives proliferation
4) Can also occur due to fertilisation of a normal egg by a sperm with unreduced paternal chromosomes (46XY)
Outline the classification of Epithelial Ovarian Tumours
[1] Type 1
1) Low Grade
2) Relatively Indolent and arise from well characterised precursors (benign tumours) and endometriosis
3) Mutations: K-ras, BRAF, P13KCA, Her2, PTEN, beta-catenin
[2] Type 2
1) High Grade
2) Aggressive
3) P53 mutation in 75% of cases
4) NO precursor lesions
What are the Key features of Serous Tumours?
1) Most common type of Ovarian tumour
2) Usually Cystic
3) 30-50% are bilateral
3) Benign Tumours are line by Bland Epithelium
4) Borderline Tumours have a more complex atypical lining with papillae but no invasion through the Basement Membrane
5) Malignant Tumours are invasive with a poor prognosis
