An Interesting Case of Clinically Significant Naturally Occurring Anti-Le^b Alloantibody in a Pediatric Patient

A 45-year-old female patient complains that she has been getting weaker and weaker for several months. She has no appetite and suffers from diarrhoea. Immunofixation shows monoclonal lambda light chains in the serum. What is your tentative diagnosis?

A 48-year-old female patient feels listless and reports petechiae occurred for the first time. In the last 3 days, she had reportedly developed severe toothache and fever. The blood count shows severe pancytopenia. What are your first steps?

The 49-year-old female patient presents with significant swelling of the right arm. She reports having been diagnosed with breast cancer 1½ years ago, followed by surgical removal of the tumour. She had then received chemotherapy and irradiation. How do you proceed?

A 53-year-old man complains of increasing pain in the left anterior pelvis, which is described as movement-dependent with radiation into the left lower extremity. For several months, he had noticed bloody urine from time to time without pain during micturition. What are your suspicions?