Introduction

Osteoporosis is a major public health concern. It is a common skeletal disease characterized by low bone strength and increased risk of fracture. Fractures are associated with adverse outcomes including acute and chronic pain, diminished quality of life disability, high risk of future fractures, increased mortality, and substantial healthcare expenses (1). Gender, age and race are important risk factors for osteoporosis. Certain medications (in particular glucocorticoids) and various medical conditions, such as renal failure, hypogonadism, hyperparathyroidism, malabsorption, alcoholism, and multiple myeloma (MM) are important secondary causes of osteoporosis (2).

Case Report

A 27 year-old-man was admitted to our hospital with pain in the back. Bone mineral density evaluation revealed severe osteoporosis at L1-L4 vertebra (T score: -4.01) as well as on femur. Causes of secondary osteoporosis, such as thyrotoxicosis, glucocorticoid therapy, hypercortisolemia, renal failure, hypercalciuria, hyperparathyroidism were excluded. Deoxipyridinium level was 11.8 nMDP/mMKr (N: 2.3-5.4), and osteokalsin level was 5 ng/mL(N: 3.1-13.7). Laboratory examination revealed hypoglobulinemia. Further evaluation of the immunoglobulin (Ig) levels were compatible with panhypoglobulinemia [(Ig G: 223 mg/dL (751-1560); Ig A: <6.67 mg/dL (82.0-453); IgM: <4.17 (46.0-304); IgG1: 173; IgG2: 120; IgG3: 26.8; IgG4: 7.10). The level of vitamin D (vit D: 4 (25-150)] was also low. The patient was first suspected of having common variable immune deficiency, however, he did not experience frequent infections. By carefully evaluating his chest x-ray, a lytic lesion was observed in his left humerus. He did not have anemia and elevated sedimentation was not detected. Protein electrophoresis showed hypoglobulinemia and serum kappa was 455 (170-370 mg/dL); serum lambda was: 109 (90-210 mg/dl); urinary kappa was: 10.7 (0-0.71 mg/dL); and urinary lamda was <5.00 (0-0.39 mg/dL). The level of ß2 microglobulin was normal. Hematology consultation was requested and a bone marrow aspiration was performed. Bone marrow examination revealed MM with a myeloma cell increase of 70-80% (Figure 1). The patient was diagnosed as having nonsecretory myeloma which explained his hypoglobulinemia. A chemotherapy regimen (vincristine, adriablastina, dexamethasone) was initiated and further autologous stem cell transplantation was planned. The patient had also chromosome 13 abnormality.

Discussion

Osteoporosis in men is less common than in woman and, 50% of cases are associated with an underlying secondary cause. Here, we report the case of a young-aged male patient with osteoporotic vertebral fractures as a rare presenting manifestation of nonsecretory MM. Nonsecretory plasma cell myeloma is characterized by an absence of detectable monoclonal protein in both the serum and urine. It is generally reported to comprise approximately 1% to 5 of all cases of plasma cell myeloma and, because of its rarity, requires a high index of suspicion and bone marrow biopsy to establish the diagnosis (3). Hematologic malignancies may lead to generalized osteoporosis and pathologic fractures, bone pain, and hypercalcemia. MM has the highest incidence of bone involvement of all malignant diseases. It is estimated that 70% of patients with MM present with bone pain, and up to 60% of patients will develop a pathologic fracture during their course (4). The skeletal involvement of MM is a major contributor to the morbidity and mortality associated with MM, and up to 90% of patients will develop generalized osteoporosis or lytic bone lesions (5). Presentation age is generally between 53 and 62 years. Our patient presented at a very young age in comparison to previously reported cases (4).

Patients with myeloma may experience hypercalcemia, osteoporosis, pathological fractures, spinal cord compression and severe pain. Osteoclast activating factors, such as like interleukin-6, interleukin-1β, interleukin-3, macrophage inhibitory protein 1 alpha, tumour necrosis factor-alpha, hepatocyte growth factor, and vascular endothelial growth factor activate the nuclear factor kappa B and its ligand. In addition, malignant plasma cells may decrease osteoblast differentiation and function leading to osteoporosis (6).

Our patients’ young age, absence of anemia and elevated sedimentation and absence of monoclonal proteins in serum and urine made the diagnosis difficult. The patient had been followed at different clinics for the last two years with the diagnosis of osteoporosis until consulting our department. In summary, nonsecretory myeloma, although rare, should be considered as a cause of idiopathic osteoporosis.

Ethics

Informed Consent: Consent form was filled out by all participitants.

Peer-review: External and Internal peer-reviewed.

Authorship Contributions

Concept: Kevser Onbaşı, Aysen Akalın, Design: Kevser Onbaşı, Nur Kebapçı, Data Collection or Processing: Kevser Onbaşı, Havva Üsküdar, Analysis or Interpretation: Kevser Onbaşı, Literature Search: Kevser Onbaşı, Belgin Efe, Writing: Kevser Onbaşı, Nur Kebapçı, Belgin Efe.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: This study has received no financial support.

References

1.    Lewiecki EM, Watts NB. New guidelines for the prevention and treatment of osteoporosis. South Med J 2009;102:175-179.
2.    Lash RW, Nicholson JM, Velez L, Van Harrison R, McCort J. Diagnosis and management of osteoporosis. Primary Care 2009;36:181-198.
3.    Shaw GR. Nonsecretory plasma cell myeloma-becoming even more rare with serum free light-chain assay. Arch Pathol Lab Med 2006;130:1212-1215.
4.    Emkey G, Epstein S. Secondary osteoporosis: Pathophysiology & diagnosis. Best Pract Res Clin Endocrinol Metab 2014;28:911-935.
5.    Derk JT, Sandorfi N. Nonsecretory multiple myeloma masquerading as a new osteoporotic vertebral compression fracture in an older female. J Am Geriatr Soc 2002;50:1747-1748.
6.    Walker RE, Lawson MA, Buckle CH, Snowden JA, Chantry AD. Myeloma bone disease: pathogenesis, current treatments and future targets. Br Med Bull 2014;111:117-138.