PMC4561092_01
Initial EGD performed for an acute episode of melena in a 92-year-old woman with smoldering multiple myeloma (SMM) revealed a well-organized, hemispherical, 11 x 6 cm tightly adherent clot attached to the midgastric body that that could not be detached despite vigorous endoscopic irrigation and aspiration (a). About eight, 3-5 mm wide sessile polyps (nodules) were present in the gastric fundus and body, devoid of stigmata of recent hemorrhage, two of which were present at the 8 o'clock position. Repeat EGD performed one day later revealed that the clot had mostly dissolved exposing a 2.5 x 2 cm ulcerated mass, mostly covered by a clot in the midgastric body along the lesser curvature (b).
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EGD revealed a large, hemispherical, 11 x 6 cm adherent blood clot attached to the gastric body that could not be detached despite vigorous endoscopic irrigation and aspiration (Figure 1(a)). Repeat EGD performed one day later revealed that the clot had mostly dissolved exposing a not actively bleeding, 2.5 x 2 cm ulcerated mass, mostly covered by clot in the midgastric body along the lesser curvature (Figure 1(b)).
Low-power photomicrograph of endoscopic biopsies of the gastric mass using a Congo red stain revealed rose-pink staining of the amyloid deposits (a). Low-power (b) and high-power (c) photomicrographs of Congo red stain from the same sections using polarized light revealed the classic apple-green birefringence. Note that the regions exhibiting apple-green birefringence in (b) and (c) correspond to the same regions revealing rose-pink staining in (a). Note the presence of typical gastric glands on the right sides of (a) and (b).
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Histologic staining with Congo red stain revealed positively staining deposits in the lamina propria (Figure 2(a)) that exhibited apple-green birefringence under polarized light (Figures 2(b) and 2(c)), consistent with gastric amyloidosis.
Congo red-positive sections viewed under ultraviolet light in the microdissection microscope. The amyloid fluoresces red. The drawn lines (yellow in (a), green in (b), and blue in (c)) delineate areas circumscribing the amyloid deposits that were cut out of the tissue sections for processing for mass spectrometry. The three dissections in (a)-(c) correspond to the three patient sample columns in the Scaffold illustration in Table 1. Each sample was processed in triplicate. (d) shows the amyloid fragments that have been cut out of the tissue and are now in the reaction cup for further processing (i.e., reduction of disulfide bonds, trypsin digestion, etc.) before mass spectrometry.
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Peptides were extracted from Congo red-positive areas after microdissection of paraffin-embedded stomach biopsy specimens (Figure 3); and then liquid chromatography tandem mass spectrometry (LC MS/MS) was performed on the extracted peptides which revealed a peptide profile consistent with AL- (lambda-) type amyloidosis (Table 1). Columns titled Patient Samples 1, 2, or 3 correspond to results from the 3 microdissections performed in Figure 3 (i.e., all cases analyzed by LC-MS/MS in triplicate).