P-83 Primary thyroid lymphoma presented with hypercalcemia and rapidly growing neck mass

Abstract

Abstract Introduction Primary thyroid lymphoma is an uncommon malignancy, accounting for 1% to 2% of extranodal lymphomas and 1% to 5% of thyroid malignancies. Large B-cell lymphoma is the most prevalent form of primary thyroid lymphoma. Here, we present a patient with hypercalcemia and a rapidly growing neck lesion who was diagnosed with diffuse large B-cell lymphoma of the thyroid gland. Clinical Case A 75-year-old patient presented to the emergency room with loss of appetite and decreased oral intake over the previous five days, as well as abdominal pain and inability to pass gas and feces. The nausea and vomiting symptoms began simultaneously with the abdominal discomfort. Inspection revealed a distinct, palpable, and erythematous mass in the patient's neck, which the patient reported developing within the previous three months. After noticing the growing mass and consulting her primary care physician, she was referred to an ENT specialist; a biopsy was conducted and the results were pending. Her preliminary laboratory results revealed hypercalcemia and renal failure with depressed parathyroid hormone levels. The following were the initial laboratory results: creatinine 2,14 mg/dL, Ca 13,5 mg/dL, Albumin: 4,2 g/dL, P 2,9 mg/dL, Mg:1 mg/dl, parathormone 11.6 ng/dL procalcitonin 0.04% ng/mL and hemoglobin 10.2% g/dl. Abdominal CT revealed a contracted gallbladder with stone formations in the lumen, but no other abnormalities. The patient was admitted to the internal medicine ward with an initial diagnosis of hypercalcemia and prerenal acute kidney failure as a result of decreased oral intake. The patient's hypercalcemia was determined to be PTH-independent, and malignancy was suspected due to a 4-month history of progressive neck lesion. The thyroid gland was 49×40×87mm in the right and 38×40×62mm in the left, and the isthmus was 50mm thick with lobulated outlines on contrast enhanced cervical MR. The signal intensity of parenchyma was heterogeneous. 18F-FDG PET/CT uncovered a bilateral, distinct increase in the size of the thyroid gland with protrusions to the hyoid bone in superior sequences. The solid mass was found to have diffusely increased FDG uptake and a hypermetabolic pattern, both of which are indicative of malignant characteristics. The lesions encompass the trachea and there are reports of invasion of the cricoid cartilage and thyroid cartilage. A second main malignant disease concern was raised when small intestine FDG uptake and wall thickening suggested malignancy. The patient was re-evaluated by the endocrinology clinic, and additional workup tests were ordered due to the suspicion of Riedel Struma, which was based on the control sedimentation rate of 93 mm/h and the firmness of the gland upon palpation. An open surgical biopsy was performed. The pathology report concluded that it is consistent with diffuse large B-cell lymphoma that is CD20-positive. The hematology department has scheduled chemotherapy treatment for the patient.