Question 1

On examination: jaundice; palpable non-tender mass in the right upper quadrant.

The results of his liver function tests are shown:

Urinalyis showed the presence of bilirubin. Urobilinogen was undetectable. Alpha feto-protein was normal.

What is the most likely diagnosis?

Jaundice is defined as a yellow discoloration of the skin, is is typically detectable when the serum bilirubin level is over 50µmol/L. The causes of jaundice can be classified under three broad headings: pre-hepatic, hepatic, and post-hepatic. Liver function tests are one of the most useful investigations used to give an indication of the underlying cause.

In pre-hepatic jaundice:

• The serum concentrations of ALP and ALT are usually normal
• There is a high level of circulating unconjugated bilirubin because the enzyme glucuronyl transferase is saturated and cannot conjugate the bilirubin.
• Urinalysis shows no bilirubin in the urine because unconjugated bilirubin is insoluble
• Urine will be positive for urobilinogen
• Common causes of pre-hepatic jaundice are acquired haemolytic anaemia, and other inherited genetic disorders (Gilbert's syndrome).

In hepatic jaundice:

• There is usually a marked rise in the liver enzymes ALT and AST
• Swelling of the hepatic parenchyma frequently produces an element of duct obstruction, and therefore is associated with a modest rise in serum ALP
• Urinalysis will be positive for bilirubin because the liver has conjugated the bilirubin and made it soluble
• Urobilinogen may be normal or reduced
• Common causes of hepatic jaundice include liver cirrhosis and hepatitis.

In post-hepatic jaundice:

• There is a marked rise in the level of ALP and GGT
• There may be a small rise in the level of the liver enzymes ALT and AST
• The liver conjugates bilirubin, rendering it water soluble, so urine will be positive for bilirubin
• Obstruction of the biliary tree prevents bile (and bilirubin) from entering the gastrointestinal tract, where the bilirubin is converted to urobilinogen. Therefore there is a decreased or undetectable amount of urobilinogen in the urine
• Common causes of post-hepatic jaundice include gall stones, cholangiocarcinoma, carcinoma of the head of pancreas and sclerosing cholangitis.

In this case, there is a moderate rise in the liver enzyme ALT but a marked rise in the ALP which is suggestive of an obstructive/post-hepatic picture. The presence of bilirubin but absence of urobilinogen in the urine also supports this picture. Hepatocellular carcinoma may cause an obstructive picture, but the normal alpha feto protein suggests this is less likely. Therefore the most likely diagnosis here is pancreatic carcinoma.

The diagnosis of the cause of jaundice cannot be made on the basis of the liver function tests alone. Other investigations such as ultrasonography, MRCP, ERCP, and CT should be considered.

Question 2

Which of the following is the most likely diagnosis?

The most likely diagnosis is fat necrosis. Fat necrosis typically occurs in elderly women with large breasts, or after injury to the chest, for example following a car accident when the seatbelt has squeezed the breast. This clinically presents as a firm painless lump, although there may be some redness or bruising. The only way to exclude breast cancer is FNAC.

Fibroademomas, or "breast mice", typically affect young women between the ages of 15 and 25 years. They are usually well circumscribed, firm, smooth mobile lumps. Investigation with triple assessment (clinical breast exam, breast histopathology and radiology) can diagnose the condition and exclude breast cancer.

Breast cysts and duct ectasia are disorders of involution that occur most often in older women. Breast cysts present as smooth discrete masses that can be painful. They are seen on mammography as "halos" and on ultrasound. Most cysts are asymptomatic and do not require treatment. Symptomatic cysts can be aspirated, but recurrence, or blood stained fluid on aspiration is an indication for surgical excision.

Duct ectasia typically presents with cheesy discharge and "slit like" nipple retraction. Treatment is only indicated if the discharge is worrisome or if the patient wants their nipple everted.

Duct papillomas are benign neoplasms that are very common. They usually present with blood-stained nipple discharge. Duct papillomas show little malignant potential, but treatment involves removal of the discharging duct, and allows exclusion breast cancer.

Question 3

Dermatomyositis picture

What is the most likely diagnosis?

This is the classic presentation of dermatomyositis. Dermatomyositis and polymyositis are rare disorders that involve inflammation of striated muscle causing weakness of proximal muscles. When the skin is involved, it is called dermatomyositis.

Clinical features include facial erythema, a purple "heliotrope" rash on the eyelids and periorbital area. Bluish/red nodules typically occur on the extensor surfaces and over the knuckles (Gottron's papules).

Diagnosis of the condition involves:

• Clinical appearance
• EMG reveals spontaneous fibrillation potentials at rest, short duration potentials on voluntary contraction and repetitive potentials on mechanical stimulation of the nerve
• Muscle biopsy which shows fibre necrosis and infiltration of inflammatory cells
• There is often a raised serum creatine phosphokinase.

Question 4

He has a raised serum alkaline phosphatase and normal serum calcium. PSA is normal. His x-ray shows an expansile sclerotic process.

What is the most likely diagnosis?

Paget's disease is a common disease in middle-aged and older people. Accelerated turnover of bone, with increased osteoblastic and osteoclastic activity results in disorganised bone architecture which leads to changes in the mechanical properties of the bone. Paget's disease may cause expansion of the membrane bones of the skull, with compression the acoustic nerve and deafness. In addition, pagetic bone is typically brittle, and fracture can occur with minimal or no trauma.

Question 5

Erythema Nodosum picture

Which of the following would you consider as a cause?

The history is suggestive of erythema nodosum, which presents as painful nodules, usually on the extensor aspect of the lower limbs. It is most common in young adults, especially females. It is due to inflammation of the dermis and the subcutaneous layer (panniculitis). There may be associated arthralgia, malaise and fever.

Common causes of erythema nodosum include:

1. Bacterial infections: streptococcal infections are the most common cause of erythema nodosum.
2. Drugs: The oral contraceptive pill, sulphonylureas and sulphonamides have been implicated
3. Sarcoidosis: Sarcodiosis is a multi-system disease. The most common skin manifestation of the disease is erythema nodosum.
4. Inflammatory bowel disease, in particular, ulcerative colitis, have been associated with erythema nodosum.

Other less common causes include:

1. Tuberculosis
2. Hodgkin's lymphoma
3. Pregnancy
4. Idiopathic

All patients presenting with erythema nodosum require a CXR given the differential diagnoses.