Amyloid involvement of the tongue is almost always secondary to systemic amyloidosis. Isolated amyloidosis of the tongue is relatively rare and it accounts for less than 9% of all types of amyloidosis. We are presenting a case of a 54-year-old male patient who complained of an enlarged tongue and bilateral multiple swellings on the lateral borders of the tongue, which had been there since one year. Bilaterally symmetrical, violaceous, purpuric patches interspersed with nodules were seen surrounding the eyes. Histopathologically, the lesion exhibited homogenous eosinophilic amyloid-like material. Special staining with Congo red showed amyloid material as peach red colour under light microscopy and as apple green birefringence under polarized light. Based on these observations, a definitive diagnosis of amyloidosis of tongue was made. Amyloidosis of tongue is uncommon and its features resemble those of a benign tumour. A battery of tests is necessary to differentiate localized amyloidosis from its systemic forms.
Keywords: Amyloidosis; Apple green birefringence; Polarized light; Tongue.