Abstract
Hodgkin lymphomas (HL) are lymphoid neoplasms formed by a conglomerate of malignant Hodgkin/Reed-Sternberg cells with heterogeneous non-neoplastic inflammatory cells. Classic HL (cHL), one of two major subtypes, comprises 90% of all cases. HL typically presents as asymptomatic adenopathy or mass on chest imaging; constitutional symptoms (unintentional weight loss, night sweats, fever) occur in approximately 40% of cases. Though hypercalcemia is not uncommon in HL due to increased production of 1,25(OH)2D or, less commonly, direct bony involvement, it is unusual for severe hypercalcemia and its related symptoms to be the primary reason for presentation such as in our case below.
An 87-year-old man was admitted to our institution with three days of increasing agitation and confusion in the context of several weeks of forgetfulness and decline in his daily activities. He previously lived robustly independently. His past medical history included atrial fibrillation, hyperlipidemia, and benign prostatic hyperplasia. His home medications included metoprolol, apixaban, atorvastatin, tamsulosin, finasteride and a multivitamin.
Laboratory evaluation revealed serum calcium 17.5 mg/dL and serum creatinine 3.0 mg/dL (eGFR 20 mL/min/1.73m2). Complete blood count, phosphate, magnesium and alkaline phosphatase were normal. Intravenous fluids and later pamidronate improved his calcium to the 11–13 mg/dL range. Endocrinological workup revealed PTH 7 pg/mL (nl 15–65 pg/mL), 25(OH)D 15 ng/mL (nl 20–80 ng/mL), PTHrP 0.8 pmol/L (nl <2.0 pmol/L) and 1,25(OH)2D 57 pg/mL (nl 18–64 pg/mL). Serum protein electrophoresis showed no abnormalities and lactate dehydrogenase was 230 U/L (nl 125–250 U/L)
Computed tomography (CT) of his abdomen revealed non-specific prominent mesenteric lymph nodes. Neck CT did not show any abnormal cervical or supraclavicular lymphadenopathy. Chest CT did not show any mediastinal masses, abnormal lymphadenopathy, or findings consistent with silicosis (he had a 15-year history of masonry and brick-laying). Bone scan showed asymmetric uptake in two areas of his femurs, with xrays revealing subcortical scleroic lesions. Patient declined inpatient bone marrow biopsy, and was empirically started on prednisone, with rapid improvement in calcium to 9.6 mg/dL and return to his baseline mental status. He eventually accepted and underwent bone marrow biopsy as an outpatient, which revealed marrow involvement by classic Hodgkin lymphoma. The patient was started on a regimen of brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine, with excellent clinical response.
This case illustrates an atypical, hypercalcemia-driven initial presentation of Hodgkin’s lymphoma. It also exhibits the hallmark “inappropriate normal” 1,25(OH)2D which, in the context of hypercalcemia and low PTH, suggests extrarenal (i.e. PTH-independent) production of 1,25(OH)2D.