A 70 Year Old Man Presents With Bone pains And Fatigue

A 70 year old man is brought to a primary care physician by his son because the patient has been complaining of fatigue and bone pains over the past 5 months. Although he lives alone, for the past few days he has been feeling very sick and had to call his son for help. His appetite has reduced and he feels nauseous all the time. His son feels that the patient has lost a lot of his weight during the last few months. He says due to weakness he has not been out of bed for the last 4 days.
On examination the patient appears to be slightly confused. he looks pale and malnourished.
Vitals:
Temperature = 102 F
Heart rate = 110 beats/ minute
B.P = 110/60 mmHg
Resp rate = 17 breaths /min

On abdominal examination liver was palpable 3 cm below the right costal margin.
All the bones including the upper and the lower limbs as well as the ribs were tender on palpation.

What Investigations will you order?

• Complete Blood count
• Urinalysis 
• Serum and urine assessment for monoclonal protein
• Bone marrow aspiration and/or biopsy
• Skeletal survey ( that includes a series of X rays of the skull, axial skeleton and proximal long bones).

The results shows:

• Hb = 8 g/dl. 
• Peripheral blood smear shows the following picture:

Plasma cells seen along with rouleau formation of blood red blood cells

• ESR = 148 mm/h
• Urinalysis = protein +++
• Bone marrow aspirate = a dry tap
• M protein and beta 2 microglobulin detected in the serum.
• X ray skull shows punched put lesions and the picture is shown below:

Punched out holes (arrow pointing to the prominent one).

What is the Differential Diagnosis?

• Multiple myeloma
• Malignant Lymphoma
• Plasma cell lymphoma
• Metastatic carcinoma
• Waldenstrom hypergammaglobinemia. 
• Monoclonal gammopathies of unknown origin