Prostate cancer is the most common primary tumour that metastasises to the bone.

Most common tumours causing bone metastasis (in descending order):
1. Prostate (32%)
2. Breast (22%)
3. Kidneys (16%)
4. Lungs
5. Thyroid

Most common sites of bone metastasis (in descending order):
1. Spine
2. Pelvis
3. Ribs
4. Skull
5. Long bones

The patient is on stage IV according to the Ann Arbor staging system for Hodgkin lymphoma (HL). The disease has spread beyond the lymph nodes into the liver (involvement of extra lymphatic organ).

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

Staging of HL is done according to the Ann Arbor staging system:
Stage
I: Single lymph node region (I) or one extra lymphatic site (IE)

II: Two or more lymph node regions on same side of the diaphragm (II) or local extra lymphatic extension plus one or more lymph node regions on same side of the diaphragm (IIE)

III: Lymph node regions on both sides of the diaphragm (III) which may be accompanied by local extra lymphatic extension (IIIE)

IV: Diffuse involvement of one or more extra lymphatic organs or sites

Suffix
A: No B symptoms

B: Presence of at least one of the following: unexplained weight loss >10% baseline during 6 months before staging; recurrent unexplained fever >38°C; recurrent night sweats

The combination of frequent infections, eczema, and thrombocytopaenia are characteristic of Wiskott-Aldrich syndrome, which is due to an abnormality in the WASP gene. It is an X-linked recessive disorder that causes primary immunodeficiency owing to a combined B- and T-cell dysfunction.

The other listed options are:
1. PKD1: polycystic kidney disease
2. CFTR: cystic fibrosis
3. HFE1: haemochromatosis
4. RET: multiple endocrine neoplasia, Hirschsprung’s disease

This patient is having vaso-occlusive event/crisis (thrombotic crisis) which is a type of sickle cell crisis. It may be associated with ostealgia.

There is no evidence of an aplastic crisis in this case as the haemoglobin level is reasonable with a good reticulocyte count. Conversely, the haemoglobin is not low enough and reticulocyte count and bilirubin are not high enough for a haemolytic crisis.

Sickle cell anaemia is characterised by periods of good health with intervening crises. The four main types of sickle cell crises are thrombotic crisis (painful or vaso-occlusive crisis), sequestration crisis, aplastic crisis, and haemolytic crisis.

Thrombotic crisis is precipitated by infection, dehydration, alcohol, change in temperature, and deoxygenation. Sequestration crisis is characterised by acute chest syndrome (i.e. fever, dyspnoea, chest/rib pain, low pO2, and pulmonary infiltrates). Aplastic crisis is characterised by a sudden fall in haemoglobin without marked reticulocytosis. It usually occurs secondary to parvovirus infection. In haemolytic crisis, a fall in haemoglobin occurs secondary to haemolysis. It is a rare type of sickle cell crisis.

The patient has acute promyelocytic leukaemia (APML) with associated disseminated intravascular coagulation (DIC). Although
the platelet count is high, platelet function is ineffective.

Patients may present, as in this case, with severe bleeding, and the most appropriate emergency treatment would be administration of fresh frozen plasma (FFP).

Carcinoembryonic antigen (CEA) is a known tumour marker for colorectal cancer. It is not used diagnostically, but in patients with a known diagnosis of colorectal cancer associated with raised CEA levels, it can be used to monitor disease activity and help with the early identification of disease recurrence.

Tumour markers can be divided into:
1. Monoclonal antibodies
CA 125: Ovarian cancer, primary peritoneal cancer
CA 19-9: Pancreatic cancer
CA 15-3: Breast cancer

2. Tumour specific antigens
Prostate specific antigen (PSA): Prostatic carcinoma
Alpha-feto protein (AFP): Hepatocellular carcinoma, teratoma
Carcinoembryonic antigen (CEA): Colorectal cancer
S-100: Melanoma, schwannomas
Bombesin: Small cell lung carcinoma, gastric cancer

3. Enzymes
Alkaline phosphatase (ALP)
Neuron specific enolase (NSE)

4. Hormones
Calcitonin
Antidiuretic hormone (ADH)
Human chorionic gonadotropin (hCG)

This patient meets the diagnostic criteria for neutropenic sepsis, which is a relatively common complication of cancer therapy – usually chemotherapy occurring 7–14 days after. It is defined as a neutrophil count of <0.5 x 10^9/L in a patient undergoing anticancer treatment and who has either a temperature higher than 38°C or has other features consistent with clinically significant sepsis. Management approach is the same as mentioned in this case. However, if the patient still remains unwell, then an antifungal such as amphotericin B is started after risk-stratifying the patient and carrying out investigations (e.g. HRCT and Aspergillus PCR) to determine the likelihood of systemic fungal infection.

The patient is displaying signs and symptoms of hyperviscosity syndrome, secondary to the Waldenström’s macroglobulinemia. Treatment of choice is plasmapheresis.

Waldenström’s macroglobulinemia (also called lymphoplasmacytic lymphoma) is an uncommon type of non-Hodgkin lymphoma seen in older people. It is a lymphoplasmacytoid malignancy characterised by the secretion of a monoclonal IgM paraprotein. Its features include monoclonal IgM paraproteinemia; hyperviscosity syndrome leading to bilateral central retinal vein occlusion (CRVO) and hence, visual disturbances; weight loss and lethargy; hepatosplenomegaly and lymphadenopathy; and cryoglobulinemia. It is not, however, associated with bone pain.

Thalassaemias are a group of genetic disorders characterised by decreased production of either alpha or beta chains of haemoglobin (Hb). Beta thalassaemia trait is an autosomal recessive condition in which a disproportionate hypochromic, microcytic anaemia occurs—microcytosis is disproportionate to the Hb level. It is usually asymptomatic.

Microcytic anaemia in a female should raise the possibility of either gastrointestinal blood loss or menorrhagia. However, there is no history to suggest this in the aforementioned patient. This, combined with characteristic disproportionate microcytosis and raised HbA2 levels ( >3.5%), point towards beta thalassaemia trait.

Basophilic stippling is also seen in lead poisoning but the raised HbA2 levels cannot be explained in such a case.

Leukemoid reaction has a high LAP score.

Leukemoid reaction refers to leucocytosis occurring as a physiological response to stress or infection which may be mistaken for leukaemia, especially chronic myeloid leukaemia (CML). Leucocytosis occurs, initially, because of accelerated release of cells from the bone marrow and is associated with increased count of more immature neutrophils in the blood (left-shift). In order to differentiate, LAP score is used. Leukocytic alkaline phosphatase (ALP) activity is high in a leukemoid reaction but low in CML.

LAP score is high in:
1. Leukemoid reaction
2. Infections
3. Myelofibrosis
4. Polycythaemia rubra vera
5. Steroids, Cushing’s syndrome
6. Pregnancy, oral contraceptive pill

LAP score is low in:
1. CML
2. Pernicious anaemia
3. Paroxysmal nocturnal haemoglobinuria (PNH)
4. Infectious mononucleosis

Night sweats are a B symptom in Hodgkin lymphoma (HL) and imply a poor prognosis.

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

Staging of HL is done according to the Ann Arbor staging system:

Stage
I: Single lymph node region (I) or one extra lymphatic site (IE)

II: Two or more lymph node regions on same side of the diaphragm (II) or local extra lymphatic extension plus one or more lymph node regions on same side of the diaphragm (IIE)

III: Lymph node regions on both sides of the diaphragm (III) which may be accompanied by local extra lymphatic extension (IIIE)

IV: Diffuse involvement of one or more extra lymphatic organs or sites

Suffix
A: No B symptoms

B: Presence of at least one of the following: unexplained weight loss >10% baseline during 6 months before staging; recurrent unexplained fever >38°C; recurrent night sweats—poor prognosis.

Exposure to aniline dyes is a risk factor for transitional cell carcinoma. Aniline dyes are used in dyestuffs and pigment manufacturing.

The other aforementioned options are ruled out because:
1. Feed production may expose to aflatoxin (hepatocellular carcinoma).

2. Being a military personnel may expose to mustard gas (lung cancer).

3. Rubber industry may expose to nitrosamines (oesophageal and gastric cancer).

4. Refrigerant production before 1974 may expose to vinyl chloride (hepatic angiosarcoma).

CXR, blood, and urine tests should be carried out initially to exclude an underlying malignancy. If these are normal, a CT scan of abdomen and pelvis should be arranged as the patient’s age is >40 years. Antiphospholipid antibodies should also be checked for the first unprovoked DVT/PE. There is no history, however, to support an inherited thrombophilia.

The National Institute for Health and Care Excellence (NICE) published guidelines in 2012 for the investigation and management of DVT. If a patient is suspected of having DVT, a two-level DVT Wells score should be used:

DVT likely: 2 points or more
DVT unlikely: 1 point or less

This system of points is based on the following clinical features:
1. Active cancer (treatment ongoing, within six months, or palliative)—1
2. Paralysis, paresis, or recent plaster immobilisation of the lower extremities—1
3. Recently bedridden for three days or more, or major surgery within 12 weeks requiring general or regional anaesthesia—1
4. Localised tenderness along the distribution of the deep venous system—1
5. Entire leg swollen—1
6. Calf swelling at least three cms larger than the asymptomatic side—1
7. Pitting oedema confined to the symptomatic leg—1
8. Collateral superficial veins (non-varicose)—1
9. Previously documented DVT—1
10. An alternative diagnosis is at least as likely as DVT—2

If two points or more—DVT is ‘likely’
If one point or less—DVT is ‘unlikely’

Management

1. LMWH or fondaparinux should be given initially after a DVT is diagnosed.
2. A vitamin K antagonist such as warfarin should be given within 24 hours of the diagnosis.
3. LMWH or fondaparinux should be continued for at least five days or until the international normalised ratio (INR) is 2.0 or above for at least 24 hours. LMWH or fondaparinux is given at the same time as warfarin until the INR is in the therapeutic range.
4. Warfarin should be continued for at least three months. At three months, clinicians should assess the risks and benefits of extending the treatment.
5. Consider extending warfarin beyond three months for patients with unprovoked proximal DVT if their risk of VTE recurrence is high and there is no additional risk of major bleeding. This essentially means that if there is no obvious cause or provoking factor (surgery, trauma, significant immobility, etc.), it may be implied that the patient has a tendency to thrombose and should be given treatment longer than the normal of three months. In practice, most clinicians give six months of warfarin for patients with an unprovoked DVT/PE.
6. For patients with active cancer, LMWH should be used for six months.

As both malignancy and thrombophilia are obvious risk factors for DVT, therefore, all patients with unprovoked DVT/PE who are not already known to have cancer should undergo the following investigations:
1. Physical examination (guided by the patient’s full history)
2. Chest X-ray
3. Blood tests (full blood count, serum calcium, and liver function tests) and urinalysis
4. Testing for antiphospholipid antibodies
5. Testing for hereditary thrombophilia in patients who have had unprovoked DVT/PE and have a first-degree relative who has a history of DVT/PE.

The patient has paroxysmal nocturnal haemoglobinuria (PNH). The classic sign of the disease is red discolouration of the urine due to the presence of haemoglobin and hemosiderin from the breakdown of red blood cells. As the urine is more concentrated in the morning, this is when the colour is most pronounced.

PNH is an acquired clonal disorder of haematopoietic stem cells, characterised by variable combinations of intravascular haemolysis, thrombosis, and bone marrow failure. Diagnosis is made by flow cytometric evaluation of blood, which confirms the CD55 and CD59 deficiencies and deficiency of expression of other GPI-linked proteins. This test is replacing older complement-based assays such as the Ham test and sucrose lysis test.

The patient has paroxysmal nocturnal haemoglobinuria (PNH) complicated by acute hepatic vein thrombosis (Budd–Chiari syndrome).

PNH is an acquired clonal disorder of haematopoietic stem cells, characterised by variable combination of intravascular haemolysis, thrombosis, and bone marrow failure. Diagnosis is made by flow cytometric evaluation of blood, which confirms the CD55 and CD59 deficiencies and deficiency of expression of other GPI-linked proteins. This test is replacing older complement-based assays such as the Ham test and sucrose lysis test.

Gamma delta T cells are of low abundance in the body, are found in the gut mucosa, skin, lungs and uterus, and are involved in the initiation and propagation of immune responses. Their ligands are not known in detail, but the gamma delta T cell receptors recognise intact proteins rather than MHC-presented peptides. Like alpha beta T cells, they develop in the thymus.

An MRI whole spine should be performed in a patient suspected of spinal metastasis which can occur before developing metastatic spinal cord compression. This patient has renal cell carcinoma, which readily metastasises to the bones and also has progressive back pain. He, therefore, needs urgent imaging of his spine before any neurological compromise develops. MRI whole spine is preferable because patients with spinal metastasis often have metastases at multiple levels within the spine. Plain radiographs and CT scans should not be performed as they have a lower sensitivity for revealing lesions and cannot exclude cord compression.

In general, imaging should be performed within one week if symptoms suspicious of spinal metastasis without neurological symptoms are present. If there are symptoms suggestive of malignant spinal cord compression, then imaging should be done within 24 hours.

The signs and symptoms of spinal metastases include:
1. Unrelenting lumbar back pain
2. Thoracic or cervical back pain
3. Pain associated with tenderness and worsens with sneezing, coughing, or straining
4. Nocturnal pain

Lead poisoning is characterised by abdominal pain, fatigue, constipation, peripheral neuropathy (mainly motor), and blue lines on gum margin in 20% of the adult patients (very rare in children).

For diagnosis, the level of lead in blood is usually considered with levels greater than 10 mcg/dL being significant. Furthermore, the blood film shows microcytic anaemia and basophilic stippling of red blood cells. Urinary coproporphyrin is increased (urinary porphobilinogen and uroporphyrin levels are normal to slightly increased). Raised serum and urine levels of delta-aminolaevulinic acid may also be seen, making it sometimes difficult to differentiate from acute intermittent porphyria.

There are two main reasons for using combinations of chemotherapeutic agents rather than single agents. First, different drugs exert their effects through different mechanisms, therefore, carefully combining them will increase the number of tumour cells killed in each cycle as well as decrease their chances of developing drug resistance. Second, there may be an even greater effect with drugs that are synergistic.

IgG4-related disease (IgG4-RD) is a fibro-inflammatory condition that can affect nearly any organ system: the pancreas, biliary tree, salivary glands, periorbital tissues, kidneys, lungs, lymph nodes, meninges, aorta, breast, prostate, thyroid, pericardium, and skin. The histopathological features are similar across organs, regardless of the site. IgG4-RD is analogous to sarcoidosis, in which diverse organ manifestations are linked by similar histopathological characteristics. Raised concentrations of IgG4 in tissue and serum can be helpful in diagnosing IgG4 disease, but neither is a specific diagnostic marker.

Some IgG4-RDs are:
1. Autoimmune pancreatitis
2. Riedel’s Thyroiditis
3. Mediastinal and Retroperitoneal Fibrosis
4. Periaortitis/periarteritis/Inflammatory aortic aneurysm
5. Kuttner Tumour (submandibular glands)
6. IgG4-related Mikulicz disease (lacrimal, parotid, and submandibular glands)

Group AB donors are the universal donors of FFP. This is because they produce neither anti-A nor anti-B antigens in their plasma and are, therefore, compatible with all ABO groups.

The aforementioned patient’s blood group is B meaning, thereby, she naturally produces anti-A antigens in her plasma and would need to receive plasma that does not have anti-B antigens in it. Hence, she can only receive FFP from donors of group B or AB. Moreover, as she is of childbearing age, she must receive RhD negative blood in order to avoid problems with future pregnancies if her foetus would be RhD positive.

Liver cirrhosis is not associated with hyposplenism.

Hyposplenism is caused by a variety of conditions. These are:
1. Splenectomy
2. Sickle cell anaemia
3. Coeliac disease, dermatitis herpetiformis
4. Graves’ disease
5. Systemic lupus erythematosus (SLE)

B2-microglobulin is a useful marker of prognosis in multiple myeloma (MM). Raised levels imply a poorer prognosis. Low levels of albumin are also associated with a poor prognosis.

Out of the aforementioned markers, low corrected calcium is the only biochemistry result consistent with the diagnosis. All of the other markers are elevated in TLS.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. As phosphate precipitates calcium, the serum concentration of calcium becomes low. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Patients at high risk of TLS should be given IV rasburicase or IV allopurinol immediately prior to and during the first few days of chemotherapy. Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin. Allantoin is much more water soluble than uric acid and is therefore more easily excreted by the kidneys. Patients in lower-risk groups
should be given oral allopurinol during cycles of chemotherapy in an attempt to avoid the condition.

TLS is graded according to the Cairo-Bishop scoring system as:
1. Laboratory tumour lysis syndrome
2. Clinical tumour lysis syndrome

Prostate cancer is the most common primary tumour that metastasises to the bone.

Most common tumours causing bone metastasis (in descending order):
1. Prostate (32%)
2. Breast (22%)
3. Kidneys (16%)
4. Lungs
5. Thyroid

Most common sites of bone metastasis (in descending order):
1. Spine
2. Pelvis
3. Ribs
4. Skull
5. Long bones

Extra-nodal presentation is more common in non-Hodgkin lymphoma (NHL) than in Hodgkin lymphoma (HL). Bone marrow infiltration is more common in low-grade than in high-grade NHLs.

Low-grade NHL is predominantly a disease of older people. Most present with advanced disease, bone marrow infiltration being almost invariable. Anaemia, leucocytosis, and/or thrombocytopaenia in a patient are suggestive of bone marrow involvement. For definitive diagnosis, lymph node biopsy is sufficient.

The other aforementioned statements are ruled out because:
1. Renal impairment in NHL usually occurs as a consequence of ureteric obstruction secondary to intra-abdominal or pelvic lymph node enlargement.

2. Burkitt lymphoma is a high-grade NHL, which was first described in children in West Africa who presented with a jaw tumour, extra-nodal abdominal involvement, and ovarian tumours. It develops most often in children or young adults and is uncommon in older people.

3. High-grade lymphomas are potentially curable. They have a better prognosis and are responsive to chemotherapy unlike low-grade lymphomas, which are incurable with conventional therapy.

The cytotoxic drug bleomycin can cause bleomycin-induced pneumonitis (BIP). It usually occurs during chemotherapy but can also occur up to six months post-therapy.

Involvement of lymph nodes on both sides of the diaphragm accompanied by night sweats would be staged as IIIB according to the Ann Arbor staging system for Hodgkin lymphoma (HL).

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

Staging of HL is done according to the Ann Arbor staging system:
Stage
I: Single lymph node region (I) or one extra lymphatic site (IE)

II: Two or more lymph node regions on same side of the diaphragm (II) or local extra lymphatic extension plus one or more lymph node regions on same side of the diaphragm (IIE)

III: Lymph node regions on both sides of the diaphragm (III) which may be accompanied by local extra lymphatic extension (IIIE)

IV: Diffuse involvement of one or more extra lymphatic organs or sites

Suffix
A: No B symptoms

B: Presence of at least one of the following: unexplained weight loss >10% baseline during 6 months before staging; recurrent unexplained fever >38°C; recurrent night sweats—poor prognosis.

Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Patients at high risk of TLS should be given IV rasburicase or IV allopurinol immediately prior to and during the first few days of chemotherapy. Allantoin is much more water soluble than uric acid and is therefore more easily excreted by the kidneys. Patients in lower-risk groups should be given oral allopurinol during cycles of chemotherapy in an attempt to avoid the condition.

TLS is graded according to the Cairo-Bishop scoring system as:
1. Laboratory tumour lysis syndrome
2. Clinical tumour lysis syndrome

The patient has spinal cord compression until proven otherwise. Urgent assessment is required.

Spinal cord compression is an oncological emergency and affects up to 5% of cancer patients. Extradural compression accounts for the majority of cases, usually due to vertebral body metastases. One of the most common causes of spinal cord compression is osteoarthritis. It is also more commonly seen in patients with lung, breast, or prostate cancer.

Clinical features include:
1. Back pain: the earliest and most common symptom, may worsen on lying down or coughing
2. Lower limb weakness
3. Sensory changes: sensory loss and numbness
4. Neurological signs: depending on the level of the lesion.
Lesions above L1 usually result in upper motor neurone signs in the legs. Lesions below L1 usually cause lower motor neurone signs in the legs and perianal numbness. Tendon reflexes are increased below the level of the lesion and absent at the level of the lesion.

Management options are:
1. High-dose oral dexamethasone
2. Urgent MRI for consideration of radiotherapy or surgery