Intraoral manifestation of systemic AL amyloidosis with unique microscopic presentation of intracellular amyloid deposition in striated muscles.

We report the history of a 59-year old patient with systemic AL amyloidosis of intraoral manifestation. The patient first presented with complaints about dysphagia and remarkable enlargement of the tongue with highly reduced mobility, as well as bilateral submucosal thickenings on the cheeks. Histopathological examination of the incisional biopsy of the buccal mucosa and underlying tissues revealed AL amyloidosis. The microscopic presentation was, however, unique, as the amyloid deposits were present intracellularly in the striated muscles. The subsequent bone marrow biopsy confirmed the diagnosis of primary amyloidosis/multiple myeloma - associated amyloidosis.