Background
Immunoglobulin light-chain amyloidosis is a relatively rare condition with a worldwide incidence of 5.1–12.8 cases per million person-years (Baker, 2022). It is characterized by a clonal population of immunoglobulin-secreting cells that produce a monoclonal light chain of κ or λ type as either an intact molecule or a fragment.
Case presentation
A 69-year-old East Asian (Chinese) male patient who presented with progressive dysphagia visited multiple hospitals repeatedly for more than 2 years and was finally diagnosed with immunoglobulin light-chain amyloidosis.
Conclusions
Otolaryngologists should consider immunoglobulin light-chain amyloidosis when encountering suspicious clinical manifestations and intervene early to avoid misdiagnosis.
Background
Systemic immunoglobulin light-chain (AL) amyloidosis is a protein-misfolding disease caused by the conversion of immunoglobulin light chains from their soluble functional states to highly organized amyloid fibrillar aggregates that cause organ dysfunction [2]. It is estimated to have a minimum incidence of 8–12 per million and is the cause of death in 0.58 of 1000 recorded deaths [3]. Currently, there are no precise data on its incidence in China; however, on the basis of renal biopsy data, it accounts for approximately 4% of all cases of secondary kidney disease [4]. AL amyloidosis is predominantly seen in the elderly population, and the median age of patients with this condition is 60 years. Its prevalence was slightly higher in males than in females. The prognosis of AL amyloidosis shows significant heterogeneity, with a median survival of less than 1 year in patients with severe cardiac involvement [4, 5]. The clinical manifestations of AL amyloidosis are diverse, and involve multiple organs. The kidneys and heart are the most commonly affected organs; however, there are other organs, such as the liver, autonomic or peripheral nerves, gastrointestinal tract, skin, and soft tissues, that may be affected. Although most clinical features of AL amyloidosis are nonspecific, macroglossia (enlarged tongue) and periorbital purpura are relatively specific clinical manifestations of AL amyloidosis. Herein, we report this case and expect that it will add to the existing literature on this subject.
Case presentation
A 69-year-old East Asian (Chinese) man with a 2-year history of dysphagia was admitted to the hospital. The patient experienced persistent sensation of dysphagia and pharyngeus accompanied by hoarseness and water aspiration. Over the preceding 2 years, he had experienced persistent and progressive dysphagia, loss of taste, slurred speech, and impaired tongue movement and had sought medical attention at multiple hospitals with inadequate improvement. Additionally, 2 months ago, the patient developed mild dyspnea at rest. Physical examination revealed diffuse swelling and thickening of the posterior pharyngeal wall, left side of the uvula, both arytenoids, and vocal cord mucosa. However, vocal cord movements were unaffected. The skin on his neck was stiff and lacked elasticity. Our laboratory results reported no anemia, no white blood cell elevation, or no thrombocyte abnormalities. The peripheral smear was normal and contained no atypical cells. No renal, hepatic, or electrolyte abnormalities were observed. The rheumatoid panel, autoimmune antibody levels, and liver fibrosis panel were all normal. Routine blood tests revealed elevated eosinophil counts (0.103, reference range: 0.005–0.05). Immunological items included a low Complement 3 titers (0.61 g/l, reference range: 0.79–1.52 g/l), normal Complement 4 titers (0.22 g/l), low immunoglobulin G titers (7.18 g/l, reference range: 7.51–15.6 g/l), and low IgM titers (0.32 g/l, reference range: 0.46–3.04 g/l). Pathological biopsy of the posterior pharyngeal wall and uvula revealed mild squamous epithelium with localized fibrous tissue proliferation, accompanied by collagenization and reactive lymphoid follicle hyperplasia.
After multidisciplinary joint consultation, we considered it to be an immune-related disorder and administered 12 mg of oral prednisolone. The patient’s symptoms did not improve significantly after 2 weeks of treatment. Meanwhile, we observed that his tongue was thickened with widespread nodules on its surface and slightly firm in texture but movable (Fig. 1a). On the skin beneath the lower lip and jaw, numerous pale red papules and nodules ranging in size from millet-seed-sized to soybean-sized, with no itching (Fig. 1b). Therefore, we collected the skin tissue and samples for biopsy. The skin tissue and tongue biopsies revealed stratified squamous epithelium with localized epithelial hyperplasia. In the subepithelial layer, there were focal deposits of homogeneous, eosinophilic material with intervening clefts, consistent with amyloidosis-related morphological changes. Subsequent immunoglobulin light-chain tests and bone marrow biopsies confirmed the diagnosis of systemic light-chain amyloidosis (kappa-type).