Presentations

Abstract

Introduction: Multiple myeloma (MM) is a plasma cell proliferative disorder characterized by the neoplastic proliferation of plasma cells resulting in a monoclonal gammopathy. MM rarely presents with cutaneous involvement; however, amyloidosis and autoimmune bullous dermatoses have been reported as the initial presentation of MM (Bhutani, Engineer). We report a case of a 75-year-old male who initially presented with a subepidermal IgG immunobullous dermatosis and was later diagnosed with oral amyloidosis and IgG lambda multiple myeloma-associated systemic AL amyloidosis.

Case Information: A 75-year-old male presented with hemorrhagic bullae involving the extremities and groin. Punch biopsy revealed a pauci-inflammatory subepidermal blister, and direct immunofluorescence showed IgG in a serrated pattern along the dermoepidermal junction, suggestive of either epidermolysis bullosa acquisita or bullous pemphigoid. Several years later he developed oral mucosal ulcers, in which amyloid deposition was found. Additional studies confirmed systemic AL amyloidosis and IgG lambda multiple myeloma.

Discussion/Clinical Findings: Primary systemic amyloidosis (AL amyloidosis) is commonly associated with plasma cell dyscrasia, where amyloid deposits in various organs can result in a broad spectrum of clinical manifestations, including rare dermatologic presentations like bullous lesions. The diagnosis is typically confirmed via Congo Red staining, which highlights amyloid deposits through apple-green birefringence under polarized light; however, false negatives can occur, necessitating electron microscopy in some cases. In this case, Congo Red positivity in the oral mucosa confirmed amyloid deposits, suggestive of amyloidosis. However, the differential diagnosis also included bullous pemphigoid (BP) and epidermolysis bullosa acquisita (EBA), given the presence of IgG at the dermoepidermal junction without eosinophilic amyloid deposits. The absence of multiple immunoreactants and the histopathological findings leaned more towards BP or EBA. Since immunobullous lesions can be an early manifestation of underlying plasma cell dyscrasia, recognizing this association is vital for prompt diagnosis and treatment, potentially improving patient outcomes in systemic AL amyloidosis.

Conclusion: We report an exceptionally rare case of a patient presenting initially with a SABD, who was subsequently diagnosed with systemic AL amyloidosis and multiple myeloma. This case emphasizes the rare intersection of immunobullous dermatoses, amyloidosis, and multiple myeloma, highlighting the need for a broad differential diagnosis when dealing with blistering disorders, and the importance of multidisciplinary management in similar presentations.