Case report.
Clinical history: He suffered from hypertension, well controlled with medical therapy
Case presentation: In the April 2020 a 57 years Caucasian old man was referred to our Hematologic Center by a nephrologist for anemia, renal failure, hypercalcemia and bone lesions with the suspicion of MM. The past medical history of patient reported fatigue, night swears and weight loss from January 2018. In the February 2018 it is documented a mild and progressive hypochromic-normocytic nemia (Hb 10,6 gr/dl) with hyperferritinemia, low iron blood levels and low count of reticulocytes. A colonoscopy showed two intestinal polyps with a high grade dysplasia. In the December 2019 it was performed a radiography of lumbar spine because of onset of pain with the finding of multiple lytic lesions. From January 2020 the patient was followed with blood tests with the documentation of a progressive anemia (Hgb 8,5 gr/dl), renal failure (serum creatinine 1,57 mg/dl, glomerular filtration 43 ml/min according to Modification of diet in renal disease (MDRD ), glycosuria (with normal value of glycemia and glycated hemoglobin). He was referred to Nephrology Center for a comprehensive evaluation. It was confirmed the anemia and renal failure with a slight glomerular proteinuria (0,95 gr/24 hour). Blood tests showed hypercalcemia (serum calcium 12,9 mg/dl), normal serum albumin. A skeletal survey and total body CT confirmed the multiple bone lysis interesting the whole skeleton and particularly the pelvis, bilateral femurs, dorsal vertebrae with erosion of the bone cortical. Notably it was described a lesion of the left lobe of the thyroid gland.
Initial work-up: In the first hematological examination the patient complained fatigue and diffuse skeletal pain. There were not remarkable clinical signs. The blood test confirmed the mild normocytic-normochromic anemia, hypercalcemia, high levels of serum calcium and a mild renal failure. We performed investigation focused on definition of MM diagnosis . But, no monoclonal component was detected by serum and urine protein electrophoresis, serum and urine immunofixation. The levels of serum immunoglobulins and free light chains were normal according with renal function. Bone marrow biopsy and aspirate did not show a monoclonal plasma cell infiltrate. The patient underwent treatment with fluid hydration and Zoledronic acid to correct (with a reduction of dosage according with glomerular filtrate).
Differential diagnosis: After excluding a monoclonal gammopathy our attempts were aimed to discover other neoplastic or endocrine diseases that could cause the clinical manifestations of our patient.
Further examination: A FDG PET-TC was performed to rule out further pathologic finding. This evaluation showed a diffuse hypercaptation of bone marrow and different bone sites, particularly the jaw, bilateral ribs, dorsal and lumbar vertebral vertebrae, pelvis and bilateral femurs. A CT-guided biopsy of the third dorsal vertebra was performed: the histologic examination was coherent with a “brown tumor” (fig.1a, 1b,1c).