[The incidence and significance of amyloid deposits in gingival, buccal and rectal mucous membranes (author's transl)].

The commonly-chosen location for biopsy proof of generalized amyloidosis are the gingival, buccal and rectal mucous membranes. In 100 cases of unselected autopsy material, mucosal specimens were taken from these locations and searched for the presence of local amyloid deposits. Control specimens were obtained from the liver and kidneys. Evidence of local amyloid deposits were detected in 75 of the gingival, 56 of the buccal and 33 of rectal mucosa specimens. 30 cases showed positive findings of local amyloid in all 3 locations simultaneously. Histologically, the amyloid distribution strictly followed the pericollagenous pattern. Furthermore, the tendency towards amyloid deposition diminished with increasing age. No relationship to underlying basic disease was found. In view of the frequently extensive amyloid deposits and the special structure of the tissue we object to the use of specimens from gingival mucosa to prove the existence of generalized amyloidosis. It is suggested that of all examined tissue biopsies the rectal mucosa is most suited to this purpose. The morphological differences between the mode of deposition in local and in generalized amyloidosis are discussed on the basis of the literature, as well as our own results.