Pathology Cases

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NEURO

Three year old with a few weeks history of headache and vomiting and signs of raised intracranial pressure.
Medulloblastoma - because it is a midline cerebellar tumour in a young child, with short history suggesting rapid growth and malignancy.
Primitive 'Embryonal' neoplasm shows high mitotic rate, rapid growth and is highly radiosensitive. Seeds via the CSF, hence radiation of whole neuraxis is indicated.
DDx - Astrocytoma, Ependymoma - both comparatively benign and slowly growing. Cerebellar astrocytma - has best prognosis.


Brain - 55 year old man.
Intracerebral haemorrhage (Systemic hypertension).?Charcot–Bouchard aneurysm
Cerebral vascular malformation - angioma, A-V malformation (Berry aneurysm with intracerebral rupture could give this picture). At PM in a young person unlikely to have essential HT - look for co-arctation of aorta, renal disease, polycystic kidneys or bleeding disorder eg: leukaemia.

Circle of Willis
Berry aneurysm of the Circle of Willis - Most often in anterior half of the Circle, in acute angle of branch points, particularly the junction of the anterior communicating and anterior cerebral artery or the first branch point of the middle cerebral artery.
Rupture -> sub-arachnoid haemorrhage, rupture can be entirely intracerebral if apex of aneurysm has invaginated cerebrum, large thrombosed aneurysm may have pressure effect eg on optic chiasma. Presentation usually in middle age (rare in childhood unless associated with polycystic kidneys).
Congenital weakness in media at branch points - gaps in muscle coat (not congenital aneurysm) many patients are hypertensive at least intermittently, although the link is not as strong as HTN has with primary intracerebral haemorrhage.

Surgical resection from the arm of a 25 year old man.
Von Recklinhausen's Neurofibromatosis (type 1). This is a plexiform neurofibroma - a pathognomonic lesion.
Common - skin - café au lait patches and multiple neurofibromas. Peripheral and spinal nerves- schwannomas and neurofibromas. Intracranial - acoustic neuromas, gliomas, especially optic nerve. 
Occasionally - phaeochromocytoma, medullary carcionoma of the thyroid, skeletal - bone cysts. 
Malignant change may occur in spinal or peripheral nerve sheath tumours.


CVS

Heart at PM - 70 year old.
Vegetations = platelets, fibrin and organisms (Infective endocarditis).
Strep viridans, but as this is a normal valve (you should be able to recognised that it is not a rheumatic valve) virulent organisms, such as Staph, haemolytic Strep, Pneumococcus are also possible causes.
Systemic emboli -> infarcts: brain, spleen, kidneyheart
Micro-emboli -> Osler's nodes, splinter haemorrhages. 
Infected emboli -> mycotic aneurysms 
Focal glomerulonephritis - immune complex disease.
Most common cause of death in this case is cardiac failure - acute valvular incompetence (perforation of cusps, rupture of chordae).

Adult aorta


Heart at post-mortem - middle aged man
Cardiac aneurysm.
Organisation following full thickness myocardial infarction leads to fibrous scarring and thinning of the ventricular wall. Gradual stretching of the scar tissue due to the haemodynamic stress produces ventricular aneurysm.
Cardiac failure, arrhythmias, emboli due to mural thrombus (not rupture).

Heart at post mortem - sudden death in a three month old infant.
Endocardial fibroelastosis - of infants (Not to be confused with endomyocardial fibroelastosis (EMF) of tropical origin). Rare disease of unknown cause. Presents with congestive cardiac failure in infancy. Diffusely thickened endocardium with elastic tissue proliferation. Splinting ie: restrictive effect on left ventricle Theories - foetal anoxia, stronger evidence for foetal Coxackie or mumps virus infection through maternal exposure.

Mitral valve - 57 year old woman.
Mitral Stenosis (Rheumatic mitral valve - calcification of cusps, fusion of commissures -> stenosis).
Low cardiac output, episodes of acute pulmonary oedema, atrial fibrillation, haemoptysis, pulmonary hypertension, infective endocarditis, systemic emboli.
Chordae of mitral valve are likely to be thickened and shortened, left atrium dilated and may contain thrombus, other valves especially the aortic, may also show changes of old rheumatic fever, left ventricle normal in pure stenosis but often dilated and hypertrophied because stenotic valve is nearly always also incompetent. Right ventricular hypertrophy develops due to pulmonary hypertension.

MICRO

Parasite
Beef tapeworm - Taenia saginata (pork tapeworm is much shorter).
Human is definitive host. Adult worm in small intestine -> proglottides shed into faeces -> ingested by cattle -> embryo released in intestine invades wall -> haematogenous spread to muscle -> develops into cysticercus form -> man infected by eating uncooked beef.


GIT

Surgical resection of small and large bowel from a 30 year old.
Crohn’s disease (Thickening and narrowing of small bowel - at bottom (string sign on X-ray)).
Local - obstruction, fistulae, malabsorption, perianal abscess, rectal bleeding, (Carcinoma and lymphoma - rare) Systemic - weight loss, malabsorption, erythema nodosum, pyoderma grangrenosum, iritis, arthritis (sometimes associated with ankylosing spondylitis).


Small bowel
Meckel's diverticulum - Congenital remnant of omphalomesenteric duct.
Gastro-intestinal haemorrhage, perforation, intussuception, ileal inflammation and ulceration induced by acid production from ectopic gastric mucosa, clinically may mimic appendicitis.

Large Bowel
Familial adenomatous polyposis coli - autosomal dominant condition.
Polyps usually begin to appear in second decade.
100% life time risk of malignant transformation

Oesophagus and stomach from a 70 year man - sudden death.
Mallory – Weiss Syndrome (Oesophageal laceration giving massive haemorrhage).
Repeated, forceful vomiting
Many patients are chronic alcoholics in whom a bout of vomiting terminates in fatal haematemesis. A hiatus hernia is sometimes present.

28 year old female with bloody diarrhoea.
Active ulcerative colitis.
Local - severe bleeding, toxic megacolon, perforation, carcinoma in longstanding total colitis 
Systemic - Anaemia, weight loss, electrolyte disturbance, pericholangitis, arthritis, uveitis, ankylosing spondylitis, erythema nodosum, pyoderma gangrenosum, amyloid.


GUM

Testis from a 23 year old man.
Seminoma or teratoma This is teratoma, it has a typical variegated appearance and is partly cystic. Seminoma generally has a homogeneous appearance and affects slightly older men (Not lymphoma, which affects much older men 60+ and gives diffuse involvement of whole testis).
Cryptorchidism predisposes
Serum tumour markers - alpha fetoprotein and HCG, lymphangiogram, Chest X-ray, CT.

RESP

Carcinoma of the bronchus.
Carcinoma of the bronchus (Bronchial obstruction - pneumonia, haemoptysis, hilar extension -> recurrent laryngeal nerve palsy, apicallesion -> Horner's syndrome, Pleural and pericardial involvement -> effusions Lymph node metastases -> SVC obstruction).
Cachexia, Metastases - widespread eg: brainliver, adrenal Paraneoplastic syndromes - ectopic hormone secretion eg: ACTH, ADH, PTH. Neuromyopathy.

Thin slice of lung - middle aged man.
(Centriacinar emphysema) Enlargement of the air spaces distal to the terminal bronchiole.
This is destructive emphysema (as opposed to mild distensive form). Smoking is the single most important aetiological factor. Substances in cigarette smoke promote the accumulation of neutrophil leucocytes in the lung - elastases released from neutrophils cause breakdown of alveolar walls. The normal neutralising role of alpha-1-antitrypsin is temporarily overwhelmed by the influx of cells and release of contents. It has also been suggested that smoke has an inhibitory effect on the action of alpha-1-antitrypsin. A1AT deficiency (PiZZ) and smoking are synergistic - usually giving servere panacinar emphysema.


Lung from 70 year old woman - short, acute illness.
Lobar pneumonia.
Pneumococcus (types 1, 3, 7, 2). most common in CAP in this age
Klebsiella, Pseudomonas, Proteus, Legionnaire's diseas, Haemophilus influenzae and Moraxella catarrhalis. Mycobacterium tuberculosis

HEPATOLOGY

Liver at post mortem - 65 year old woman.
Liver abscess (Strep milleri, Amoebae - Entamoeba histolytica).
Strep milleri - gut organism - haematogenous spread to liver to form primary inflammatory lesion (eg: acute appendicitis may exist sometimes) no primary lesion detected Amoebae - amoebic colitis spread via portal venous system

Liver
Cirrhosis
Common causes - cryptogenic (possibly these are immunological), alcohol, post-viral hepatitis 
Less common causes - primary biliary chrrhosis, Wilson's disease, drugs eg alpha methyl dopa 
Children - A1AT deficiency, galactosaemia, Wilson's disease 
Women - PBC- especially in middle aged women.

O&G
Endometrial Adenocarcinoma
PMB (commonest in post menopausal woman), menorrhagia.
Obesity, hypertension, nulliparity (prolonged oestrogen stimulation), diabetes.
Surgery with or without radiation, depending on the degree of differentiation and depth of penetration of the myometrium. Chemotherapy only when there is dissemination.

36 year old female with intermenstrual bleeding.
Invasive carcinoma of the cervix - Cervical smears (exfoliative cytology), colposcopy, cervical biopsy or loop excision
Correlation with early age of starting sexual relations, multiple partners, high risk male. Human Papilloma Virus infection (HPV). Susceptible proliferating cells of squamo-columnar junction in young women exposed to oncogenic virus (HPV 16 or 18).



NEPHROLOGY

Male 58 years - nephrectomy specimen.
Renal cell carcinoma (adenocarcinoma of proximal tubule epithelium) - Haematuria, weight loss, mass, flank pain, Pyrexia of Unknown Origin, anaemia, hypertension.
Raised ESR, Low Hb, (occasionally polycythaemia - due to erythropoietin secretion but may go up instead!), hypercalcaemia night sweats etc.

Papillary necrosis, occurs infants, septicaemia - small abscesses in parenchyma.
(mnemoic for RPN causes:  POSTCAERDS: pyelonephritis, obstruction of the urogenital tract, sickle cell disease, tuberculosis, chronic liver disease, analgesia/EtOH abuse, renal transplant rejection, diabetes mellitus, and systemic vasculitis)
Complications: dead papilla cells act as nidus for bugs - florid pyelonephritis, perirenal abscesses, and sepsis. Calculous formation compounds the necrosis because certain bacteria thrive within the calculi. Calculi can also propagate, which may lead to further obstruction, increased pyelovenous pressure, and worsened ischemia.
Always consider sloughed papillae as a cause of ureteral obstruction in the differential diagnoses of flank pain, colic, and hematuria, especially when no calculi are visible and particularly in patients with diabetes.
The development of transitional cell carcinoma of the renal pelvis or calyces is a serious complication, particularly in patients with papillary necrosis associated with analgesic abuse.


MSK

Elderly woman femur

Fracture of the femur - Osteoporosis (osteomalacia may co-exist especially in the elderly), metastatic carcinoma.
Blood loss -> heart failure, fat embolism, post-op DVT -> pulmonary embolism.


Robbins Basic Pathology, Robbins Pathologic Basis of Disease, Robbins Review of Pathology (MCQs - very path-y), Robbins Flash Cards, Baby Robbins, Robbins Atlas - some exact same images come up in the exam, 100 Cases in ClinicalPathology - possibly the best Qbank for the practical