Pathology

Question 1

Thymoma

Answer 1

Pemphigus
Thymomas are the most common tumour of the thymus. Approximately 40% are malignant. Paraneoplastic syndromes can result in pemphigus. Paraneoplastic pemphigus has erythematous, scaly plaques in a lupus-like butterfly distribution on the face as well as involving the scalp, back, chest, and intertriginous areas.

Question 2

Hepatocellular carcinoma

Answer 2

Icterus
Hepatocellular carcinoma can produce jaundice (icterus) by either obstruction of the hepatic ducts or by hepatocellualr failure.

Question 3

Lymphoma

Answer 3

Erythema multiforme
There are many aetiological causes of erythema multiforme including

ul>
Infection (bacterial, fungal, parasitic and viral)
Drugs (penicillins, cephalosporins, anticonvulsants, etc)
Immunological disorders collagen diseases, vasculitides, leukaemia, multiple myeloma, myeloid metaplasia, polycythemia and non-Hodgkin lymphoma.

Question 4

Gastric carcinoma

Answer 4

Acanthosis nigricans is most commonly associated with intra-abdominal neoplasms. Although acanthosis nigricans can also occur without an associated malignancy, the new appearance of extensive acanthosis nigricans in an older patient should prompt additional investigation for an internal cancer.

Question 5

Areas of necrotic mucosa with an off-white slough covering most of the sigmoid colon and rectum.

Answer 5

Pseudomembranous colitis
Pseudomembranous colitis is a specific form of infective colitis associated with hospital patients receiving antibiotics. The pseudomembrane is produced from necrotic mucosa and exudates.

Question 6

Generalised continuous epithelial oedema with a fine granular appearance. There are patches of erythema, contact bleeding and frank ulceration.

Answer 6

Ulcerative colitis
In ulcerative colitis the earliest changes noted at colonoscopy are a loss of the vascular pattern due to oedema obscuring the submucosal vessels. The oedema also produces the granular appearance as described.

As the condition becomes more severe erythema, contact bleeding and ulceration result. Recurrent attacks followed by repair produce mucosal regeneration nodules or pseudopolyps. Pseudopolyps represent tags of mucosa that have partially detached during healing and remain as projections.

Question 7

Areas of normal appearing mucosa with interdispersed areas of oedematous mucosa penetrated by deep fissuring ulceration.

Answer 7

Crohns colitis

Small aphthous ulcers are the early feature of Crohn’s disease, in contrast to the erythema and loss of the vascular pattern in ulcerative colitis.

In more severe disease the oedematous mucosa is penetrated by deep fissuring ulceration to give a cobblestone appearance. Multiple biopsies should be taken, as the presence of granulomata will confirm the diagnosis.

Question 8

This cancer is autosomal dominant and affects the eye.

Answer 8

Retinoblastoma

Patients who suffer from retinoblastoma are found to have the autosomal dominant tumour suppressor gene RB1.

Question 9

Commonest intra-abdominal childhood malignancy of primitive renal tubules and mesenchymal cells.

Answer 9

Wilms’ tumour

Wilms’ tumour occurs in children alone. It is treated well by surgery and chemotherapy.

Question 10

Tumour suppressor genes affected in this familial cancer include MLH1 and MSH2.

Answer 10

Hereditary non-polyposis colonic carcinoma (HNPCC)
MLH1 and MSH2 are found in patients who are suffering from hereditary non-polyposis colon cancer, and also some cases of endometrial cancer.

Question 11

The tumour suppressor gene involved in this autosomal dominant syndrome is associated with multiple colonic polyps.

Answer 11

Familial adenomatous polyposis

Familial adenomatous polyposis sufferers have the APC tumour suppressor gene. FAP affects the colon.

Question 12

Associated with a defect in DNA gyrase.

Answer 12

Xeroderma pigmentosa
Xeroderma pigmentosum affects the skin, and having the XP gene increases the chances of developing skin cancer by over a 1000 times.

Question 13

Bronchial carcinoma with a couple of peribronchial and ipsilateral hilar lymph nodes involved but no evidence of metastases.

Answer 13

T2, N1, M0
The TNM system is used to describe the extent of oncogenesis from a cancer.

T denotes the tumour size, N denotes the nodal involvement, and M denotes whether metastasis is found.

TX is used to show that positive cytology was found, however the location of the tumour is unknown or is too small to show on CT or MRI.

Question 14

A large bronchial carcinoma with widespread nodal involvement and bony metastases.

Answer 14

T4, N3, M1

Question 15

Weight loss in a smoker with normal chest x ray but positive sputum cytology for carcinomatous cells.

Answer 15

TX, N0, M0

Question 16

The following conditions all can cause a pleural effusion.

Which of the following would typically cause a transudate (

Answer 16

Nephrotic syndrome

All inflammatory and malignant causes of pleural effusions are exudates (>30 mg/L protein).

Nephrotic syndrome, liver cirrhosis and heart failure would be examples of a transudate.

Question 17

Shortly after birth a newborn baby is noted to be drooling excessively.
A diagnosis of oesophageal atresia is made.
Which of the following is not associated with oesophageal atresia?
(Please select 1 option)
Aspiration pneumonia
Cyanosis during feeding
Empty stomach on USS
Oligohydramnios
Tracheo-oesophageal fistula

Answer 17

Oligohydramnios

Infants with oesophageal atresia are often diagnosed before birth by a finding of polyhydramnios (due to their inability to swallow amniotic fluid).

Eighty five per cent of patients with oesophageal atresia have a tracheo-oesophageal fistula which causes cyanosis during attempted feeding and aspiration pneumonia.

On USS the stomach would be expected to be empty.

Question 18

A 9-year-old boy is admitted with acute onset of abdominal pain that has localised to the right iliac fossa. He is found to be pyrexial with localised peritonism in the right iliac fossa.
What is the main cell type involved at a cellular level in this child's condition?
(Please select 1 option)
	 Eosinophils
	 Erythrocytes
	 Macrophages
	 Monocytes
	 Neutrophils

Answer 18

Neutrophils This is the correct answerThis is the correct answer
This child is most likely to have appendicitis.

Neutrophils are the main cell type involved in acute inflammation.

Eosinophils are predominantly involved in hypersensitivity.

Erythrocytes are red blood cells and macrophages are the main effector cells in chronic inflammation and only play a minor component in acute inflammation.

Macrophages are derived from monocytes in the circulation.

Question 19

A 37-year-old dog breeder is bitten by one of his dogs. He does not seek medical attention until four days later when the wound has become red, swollen and is discharging a mucopurulent fluid.
Which of the following organisms is most likely to be causing the infection?
(Please select 1 option)
	 Pasteurella multocida
	 Staphylococcus aureus
	 Streptococcus milleri
	 Streptococcus pneumoniae
	 Streptococcus pyogenes

Answer 19

Pasteurella multocida

Pasteurella multocida is commonly found in dog bites and cat scratches.

Staphylococcus aureus is a common cause of cellulites and infected ulcers.

Streptococcus milleri is a common cause of infection following human bite.

Streptococcus pyogenes is a common cause of necrotising fasciitis.

Question 20

A 24-year-old lady who is four weeks post partum presents complaining of a hot painful lump in the right breast.
Examination reveals cellulitis overlying a fluctuant tender lump. Aspiration is performed and 10 ml of pus are obtained, which are sent for culture.
What is the most likely causative organism?
(Please select 1 option)
Escherichia coli
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pyogenes
Streptococcus milleri

Answer 20

Staphylococcus aureus

This lady has a lactational abscess.

The most common causative organism is Staphylococcus aureus which is thought to be acquired from the infant’s oropharynx, since 50% of infants are colonised with Staphylococcus aureus by the second day of life.

Non-lactational abscess are often also caused by Staphylococcus aureus, but anaerobic infection is also common.

Question 21

A 37-year-old lady who has had low back pain radiating to her calf for six weeks, presents to the emergency department. She reports severe abdominal pain and in the last 12 hours she has been unable to micturate.
Rectal examination reveals an empty rectum and altered peri-anal sensation. Neurological examination of her limbs reveals weakness in both legs but upper limbs are normal.
What is the most likely diagnosis from the following list?
(Please select 1 option)
Central disc prolapse at C6/7
Central disc prolapse at L4/5
Constipation
Lateral disc prolapse at C6/7
Multiple sclerosis

Answer 21

Central disc prolapse at L4/5

This lady has symptoms and signs of a cauda equina compression - she cannot micturate, has weak legs and altered peri-anal sensation.

Lateral disc prolapse would cause severe pain in the affected limb.

Multiple sclerosis can cause neurological symptoms but given this lady’s previous back pain, a disc problem is much more likely.

Constipation would not cause neurological signs.

A problem at the cervical level would cause symptoms in the upper limbs.

Question 22

A 58-year-old woman presents to the neurosurgical clinic having been investigated for new onset epilepsy, accompanied with severe headaches.
CT and MRI have shown a space occupying lesion in the frontal lobe that has an enhancing ring around an area of necrosis.
What is the most likely diagnosis from the list below?
(Please select 1 option)
Astrocytoma
Ependymoma
Glioblastoma
Meningioma
Oligodendroglioma

Answer 22

Glioblastoma

The site of the tumour excludes a menigioma as it is reported to be in the frontal lobe and as such is intrinsic.

Ependymomas arise from an ependymal surface usually the fourth ventricle.

Glioblastomas are the most common intrinsic brain tumour accounting for between 30-50% of brain tumours in adults, with a peak incidence between 55-65 years of age. The CT and MRI findings are also typical of a glioblastoma.

Astrocytomas account for about 10% of primary brain tumours in adults, but are more common in children.

Oligodendroglioma account for 3%.

Question 23

A 59-year-old lifelong smoker presents to her GP complaining of increasing shortness of breath and has noticed ptosis and constriction of her pupil.
She is referred by her GP for a chest x ray that is reported as showing an apical mass. Biopsy confirms a malignant tumour.
What is the eponymous diagnosis?
(Please select 1 option)
	 Horner's syndrome
	 Pancoast's tumour
	 Peyronie's disease
	 Pott's cancer
	 Wilms' tumour

Answer 23

Pancoast’s tumour

This lady has almost certainly got a Pancoast’s tumour (first described by Henry Pancoast, an American radiologist, in 1924). It is a neoplasm of the apex of the lung that typically invades the chest wall and brachial plexus.

The ptosis and constriction of her pupil is suggestive of a Horner’s syndrome but this is a consequence of her Pancoast’s tumour (ususally a non-small cell carcinoma).

Other structures an apical tumour (superior sulcus tumour) may locally invade or compress are:

phrenic nerve
vagus nerve
suclavian vein and artery
brachiocepalic vein (superior vena caval syndrome), and
brachial plexus.
Peyronie’s disease is hardening of the corpora cavernosa of the penis caused by scar tissue.

Pott’s cancer is a scrotal cancer (of historical interest) caused by coal tar exposure.

A Wilms’ tumour is a malignant tumour of the kidney that usually occurs in childhood.

Question 24

A 67-year-old smoker presents to the haematuria clinic with a two week history of frank haematuria. He has no previous urological history. He is a lifelong smoker.
Examination is unremarkable. USS of his pelvis demonstrates a filling defect on the wall of the bladder.
From the following list what is the most likely diagnosis?
(Please select 1 option)
Bladder adenocarcinoma
Bladder diverticulum
Bladder stone
Bladder squamous cell carcinoma
Bladder transitional cell carcinoma

Answer 24

Bladder transitional cell carcinoma This is the correct answerThis is the correct answer
The filling defect on the bladder wall in conjunction with haematuria is suggestive of a bladder tumour of which the most common is transitional cell carcinoma.

Bladder diverticula do not usually cause haematuria.

Bladder stones usually present with a mobile defect in the bladder.

Question 25

A 38-year-old fair haired woman presents to the surgical clinic complaining that a longstanding mole has increased in size, become itchy and bled recently. An excision biopsy is performed and confirms that the mole is malignant. Which of the following is a recognised staging system for this condition? (Please select 1 option) Barrett’s thickness Breslow thickness Gleason score Noonan system Nottingham prognostic index

Answer 25

Breslow thickness Breslow thickness is used to stage and predict prognosis in malignant melanoma. Clark's level and the AJCC staging system are also used. Barrett's mucosa is the name given to intestinal metaplasia of the lower oesophagus. Gleason score is used in prostate cancer diagnosis. Nottingham prognostic index is used to predict prognosis in breast cancer.

Question 26

``` A newborn infant is born with a protrusion of his abdominal contents (liver, spleen, intestine and bladder) in a sac from which the umbilical cord arises. What is the diagnosis? (Please select 1 option) Cryptorchism Exomphalos Gastroschisis Hirschsprung’s disease Imperforate anus ```

Answer 26

Exomphalos All of the features described are consistent with exomphalos. In this condition the abdominal contents are contained in a sac. The main differential would have been gastroschisis in which there is no sac and the umbilical cord arises from its normal position. Crytorchism describes the presence of a testicle in an abnormal position. Hirschsprung's disease is a cause of childhood constipation due to absence of autonomic ganglion cells in the Auerbach's plexus in the large intestine. Imperforate anus is a birth defect in which the rectum is malformed.

Question 27

``` A 2-year-old girl is brought to the emergency department by her parents who report she has had a sudden onset of breathing difficulty. She has no cough. On examination she has audible stridor and is drooling saliva from the mouth. She has not received any vaccinations. What is the likely causative organism? (Please select 1 option) Haemophilus influenzae Influenza virus Type A Legionella pneumonia Staphlococcus aureus Streptococcus pyogenes ```

Answer 27

Haemophilus influenzae This child is most likely to have acute epiglottitis. Croup is an alternative diagnosis however this usually presents with a cough and a longer duration of symptoms. Haemophilus influenzae infection is the usual causative organism for epiglottitis.

Question 28

An 87-year-old lady is admitted to the orthopaedic ward following a fall in which she sustained a fractured neck of the femur. She has no past medical or surgical history. She undergoes hemiarthroplasty and on her second post-operative day she is noted to have a warm, red wound and is started on an intravenous cephalosporin. This is continued for 12 days following which she develops abdominal distension and profuse diarrhoea. Plain abdominal x ray shows a dilated large bowel. Ridgid sigmoidoscopy shows an inflamed rectal mucosa with pseudomembranous patches. What is the most useful next investigation? (Please select 1 option) Barium enema Colonoscopy CT abdomen/pelvis Gastrograffin enema Stool sample

Answer 28

Stool sample This is the correct answerThis is the correct answer The clinical, radiological and endoscopic features are suggestive of colitis and with the history of prolonged broad-spectrum antibiotic use Clostridium difficile pseudomembranous colitis needs to be excluded. This can be achieved by examination of the stool for C.difficile toxins. Barium enema, gastrograffin enema and CT have no role in diagnosis this condition. Colonoscopy could be considered if ridgid sigmoidoscopy had been normal and C.difficile toxins had been negative, although it would carry a risk of perforation.

Question 29

A 78-year-old man presents to his GP complaining of new onset facial paralysis affecting the left side of his face. Examination reveals facial weakness affecting the left side of his face, including his forehead. He also has a prominent hard lump which is tethering the skin below his external auditory meatus behind the ramus of the mandible. What is the most likely cause for his facial weakness from the list below? (Please select 1 option) Adenocarcinoma of the parotid gland Cerebrovascular accident Pleomorphic adenoma of the parotid gland Ramsay Hunt syndrome Sub-mandibular pleomorphic adenoma

Answer 29

Adenocarcinoma of the parotid gland This gentleman has a facial nerve paralysis. The fact that this affects his whole face suggests lower motor neuron weakness rather than upper, which spares the muscles of the forehead. The site of lump suggests disease of the parotid gland, through which the facial nerve runs. Benign parotid disease does not cause facial nerve palsy.

Question 30

A 72-year-old retired dock worker presents to his GP complaining of increasing shortness of breath. He is referred for further investigation and a CXR shows asbestos plaques and a large pleural effusion. Biopsy of his pleura confirms a malignant tumour. Which of the following is the commonest cause of malignant pleural tumours? (Please select 1 option) Adenocarcinoma Large cell carcinoma Mesothelioma Small cell carcinoma Squamous cell carcinoma

Answer 30

Mesothelioma Mesothelioma is the only malignant tumour of the pleura. It almost always arises in individuals who have been exposed to asbestos. It is a rare tumour with an incidence of approximately 7-40 per 1000000 people. Dock workers have an occupational peak exposure to asbestos due to its former common use as insulation material.

Question 31

A 58-year-old lady is admitted with abdominal distension. Clinical examination reveals gross ascites. Subsequent CT of her abdomen and pelvis shows an abnormal right ovary and thickened omentum; the liver shows no abnormality. Which of the following investigations would be most useful in this lady's management? (Please select 1 option) αFP CA 125 CA 19-9 CEA Paraproteins

Answer 31

CA 125 The clinical information points to a diagnosis of ovarian cancer in this lady. CA 125 is a tumour marker for ovarian cancer. αFP is increased in the presence of liver disease, but markedly increased in hepatocellular carcinoma, and also elevated in germ-cell tumours of the testis. CA 19-9 may be useful to monitor the effects of treatment in pancreatic cancer. CEA is secreted by some colorectal tumours and may be useful in the follow up of patients with colorectal carcinoma. Paraproteins are elevated in multiple myeloma.

Question 32

``` A 28-year-old Afro-Caribbean lady undergoes excision of a sebaceous cyst from her back. Initially the wound heals well without complication. Subsequently the scar becomes raised and grows to extend beyond the margins of the original incision. The scar remains unchanged for 10 years after. What is the probable diagnosis? (Please select 1 option) Contracted scar Hypertrophic scar Keloid scar Koebner's phenomenon Marjorlin's ulcer ```

Answer 32

Keloid scar The overgrowth of the scar beyond the margins of the initial incision point to this being a keloid scar. Hypertrophic scars are usually confined to the limits of the initial incision and usually "mature" with time to shrink down. Risk factors for the development of keloid scars include: Afro-Caribbean/Oriental origin, and surgery to the back, chest, shoulders and ear lobes. Koebner's phenomenon relates to the formation of a psoriatic plaque in a wound. Marjolin's ulcer is a squamous cell carcinoma arising in a pre-existing ulcer.

Question 33

A 35-year-old woman is seen on the emergency intake with abdominal pain. She admits to having been recently referred to an endocrinologist by her general practitioner for investigation of Addison's disease. Which biochemical result would be in keeping with a diagnosis of Addison's disease? (Please select 1 option) A low urea Hyperglycaemia Hyperkalaemia Hypernatraemia Hypokalaemia

Answer 33

Hyperkalaemia The classical biochemical features of Addison's disease are ``` Hyperkalaemia Hyponatraemia A raised urea Hypoglycaemia. Clinical features of Addison's disease include ``` ``` Hyper-pigmentation Weight loss Lethargy Hypotension. The diagnosis of adrenal insufficiency can be confirmed using an adrenocorticotropic hormone (ACTH) stimulation test. ``` It is also crucial to ensure adequate glucocorticoid levels pre-and post-operatively to prevent adrenal crisis.

Question 34

``` A 10-year-old girl attends the emergency department with a swollen tongue and shortness of breath after eating strawberries. Of what type of hypersensitivity reaction is this an example? (Please select 1 option) Type I hypersensitivity Type II hypersensitivity Type III hypersensitivity Type IV hypersensitivity Type V hypersensitivity ```

Answer 34

Type 1 According to the Gell and Coombs' classification ``` Anaphylactic shock Food allergies Asthma and Hay fever are all examples of type I hypersensitivity reactions. ``` Exposure to an allergen leads to the formation of IgE and the release of inflammatory mediators such as histamine.

Question 35

``` A 69-year-old man undergoes selective portal vein embolisation prior to surgery for hepatic metastases. What overall growth effect is achieved in the non-embolised parts of the liver by the embolisation procedure? (Please select 1 option) Dysplasia Hyperplasia Hypertrophy Metaplasia Neoplasia ```

Answer 35

Hypertrophy Hypertrophy occurs when there is an increase in the size of cells but the number of cells does not change. In the case of portal vein embolisation, an increasingly utilised technique, the branch of the portal vein supplying the diseased liver is embolised with the effect of causing atrophy of the embolised segment and hypertrophy of the remaining liver. This then allows adequate hepatic reserve for a major resection.