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Atypical Presentation of Multiple Myeloma in a 26 Years-Old Young Male with Acute Renal Impairment

Multiple myeloma is characterized by a malignant proliferation of bone marrow plasma cells leading to the production of monoclonal paraproteins in the blood and urine. This pathology occurs more often in men with an average of 65 years old and very rarely in younger patients. We present here a case of a 26 years-old male diagnosed with multiple myeloma. He presented with acute renal impairment (DRA) as the first sign of multiple myeloma. Laboratory data showed the presence of monoclonal proliferation of immunoglobulins with increased serum level of light chains and 34% presence of plasma cells in myelograms. Renal biopsy confirmed the diagnosis of acute renal injury from light chain deposition. The patient started treatment with chemotherapy and immunosuppression that was accompanied by clinical improvement and stabilization of renal function. By presenting this clinical case, we want to show that multiple myeloma can be the cause of acute alteration of renal function in a very young patient.


Introduction
Multiple myeloma is a hematologic neoplasm originating from plasma cells that are normal bone marrow populations. Plasma cells are part of the white blood cells that build the immune system. Under normal conditions plasma cells produce various antibodies that fight infections while in myeloma, plasma cells proliferate and produce increased amounts of of a specific antibody known as paraprotein that has no function. Multiple myeloma is the second most common cause of hematologic neoplasms after lymphoma [1]. The incidence of multiple myeloma is 5: 100 000. The average age of diagnosis is approximately 65-70 years and only 37% of patients diagnosed are under 65 years [2]. Multiple myeloma is a very rare pathology in individuals under 30 years of age and only a few cases have been described in the literature [3]. Since the incidence of multiple myeloma is very low under 30 years (0.3%) [4], the characteristics and prognosis of these patients are not very well known and the literature review is based only in the clinical presentation of cases or in studies with limited number of patients.
What causes multiple myeloma are still unknown but it is thought to be a combination of genetic and environmental factors. The physiopathology of renal damage in multiple myeloma is heterogeneous however in most cases it is associated with immunoglobulins, and especially with the deposition of light strands giving various damage to the kidneys, but mainly tubule-intersticial type [5]. In total 20% of patients with multiple myeloma have renal involvement at the time of diagnosis and 40% will develop renal disease during the course of pathology. Rarelly in literature are described cases of patients with multiple myeloma in the third decade of life and accompanied by renal involvement.
Typical myeloma with renal involvement is characterized by hypercalcemia, impaired renal function, anemia, and osteolytic lesions. Anemia is present in 73% of cases with multiple myeloma, while renal damage in 50% of them [6]. Acute renal damage in patients with multiple myeloma is characterized by high morbidity and high mortality.
Therefore early diagnosis and immediate initiation of treatment is necessary to improve renal function. Despite the very low incidence of multiple myeloma at a young age, we should consider multiple myeloma as an ethiological cause, after excluding other possible causes of altered renal function, Renal biopsy is the main examination to confirm renal involvement from multiple myeloma and an important indicator for the prognosis of the disease.

Case Presentation
A 26 years-old young male, presented in the internal medicine emergency of the ''Mother Teresa University Hospital Center ". After a detailed medical history was taken, his complaints were: low back pain for two months,

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respiratory examination showed broncho-vesicular respiration. The patient was hospitalized in the Nephrology Service for acute impairment of renal function. Routine investigations revealed normal blood counts, Table 1 showes the results of biochemical examinations.
Proteinuria was 2.5 g% in the 24-hour urine examination in 1.7 L volume. In the ultrasound examination the urinary tract was normal. Both kidneys with normal position, regular contours and dimensions 12.

Discussion
Multiple myeloma is a monoclonal proliferation of plasma cells and is most often presented with hypercalcemia, anemia, altered renal function and bone lesions, characteristics that have diagnostic value for multiple myeloma [7,8]. This pathology most often affects men with an average of 65 years old [9,10] and only in 2% of cases patients under 40 years. Rare cases of multiple myeloma diagnosed in patients in the third decade of life are described in the literature [11,12]. Studies have shown that 40-50% of patients with acute renal impairment due to multiple myeloma present for the first time in the nephrology service [13]. The pathophysiology of renal damage in multiple myeloma is often multifactorial but in most cases is the result of increased immunoglobulin excretion. When these immunoglobulins combine with Tamm-Horsfall proteins they lead to tubular obstruction [14]. In these patients the immediate start of chemotherapy is accompanied by a decrease in the production of light chains and recovery of renal function. Also, the presence of altered renal function at the time of diagnosis is indicative of a poor prognosis and the patient's progress will depend on the reversibility of renal damage from multiple myeloma [15]. Based on the young age of the patient, clinical and laboratory data, the patient was considered by hematologists for initiating treatment cycles with bortezomide and dexamethasone. A meta-analysis by Dimopoulos [16]

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the characteristics of patients, their responses to treatment and survival. His study showed that the prognosis of these group of patients may be comparable to the rest of the population diagnosed with multiple myeloma as a result of using new generation of drugs [17].
This case presentation is important because it shows that although the diagnosis of multiple myeloma at a young age is very rare, we should keep a high level of clinical suspicion, in any patient presented with acute alteration of renal function of unknown etiology. Protein immune-electrophoresis should be in the diagnostic protocols of patients with DRA accompanied by other diagnostic tests necessary for the diagnosis of multiple myeloma.

Conclusion
Acute renal impairment is a complication of multiple myeloma and in any patient regardless of age, the diagnosis of multiple myeloma should be considered as a possible etiological cause when medical history, physical examination, laboratory testing and radiologic exams are in favor of the diagnosis. Timely diagnosis and immediate initiation of therapy is very important in order to treat and improve the survival of these patients with poor prognosis. Studies have not shown a difference in survival rates related to patient's age at the time of diagnosis of the disease; however patients at a younger age have less treatment-related morbidity and consequently have a better outlook and survival rates.