Anaplastic large cell lymphoma, with 1,25(OH)D-mediated hypercalcemia: A case report

Area of Science:

• Oncology
• Endocrinology
• Hematology

Background:

• Hypercalcemia is common in cancer patients, with humoral hypercalcemia of malignancy being the most frequent cause.
• 1,25-dihydroxyvitamin D (1,25(OH)2D)-mediated hypercalcemia is a rare subtype, occasionally associated with malignant lymphomas.
• The specific histological type of lymphoma linked to 1,25(OH)2D-mediated hypercalcemia remains unclear.

Observation:

• A case of an 80-year-old Japanese man with anaplastic large cell lymphoma (ALK-negative) presenting with acute hypercalcemia is described.
• Elevated serum 1,25(OH)2D levels were observed, correlating with the lymphoma diagnosis.
• Histological examination revealed CD68-positive macrophages in the tumor microenvironment.

Findings:

• The patient's serum calcium and 1,25(OH)2D levels improved following chemotherapy, suggesting a link to the lymphoma.
• The source of 1,25(OH)2D production could be lymphoma cells or tumor microenvironmental cells, such as macrophages.
• Despite investigations, the definitive source of 1,25(OH)2D in this specific case could not be identified.

Implications:

• This report highlights a previously undocumented association between anaplastic large cell lymphoma (ALK-negative) and 1,25(OH)2D-mediated hypercalcemia.
• The findings suggest that tumor microenvironmental cells may play a role in producing 1,25(OH)2D, irrespective of lymphoma histology.
• Further research is necessary to understand the clinical characteristics and prognostic implications of 1,25(OH)2D-mediated hypercalcemia in malignant lymphomas.