PMC9257741_01
(a) Narrowing of the gastric lumen in the fundus and proximal body. (b, c) Axial and coronal contrast enhanced CT sections reveal significant gastric wall thickening with effacement of the mucosal folds (red arrows) and multiple enlarged discrete lymphnodes (yellow arrow). (d-g) Axial MRI pre- and post-contrast T1 weighted images, diffusion weighted image and ADC images demonstrate the gastric wall thickening with significant restriction (red arrows). (h) Upper GI endoscopy: Nodular thickening in the fundus of the stomach causing luminal stenosis.
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As a result of the predominant upper GI complaints, the patient underwent an upper GI barium study, which demonstrated circumferential gastric luminal narrowing in the region of the fundus and body without obvious mucosal irregularity (Figure 1a). At a subsequent contrast enhanced CT scan, homogenous minimally enhancing circumferential thickening of the gastric wall (measuring ~2.5 cm) in the region of fundus and body was seen (Figure 1b, c) with associated multiple discrete similarly enhancing supra- and infra-diaphragmatic lymph nodes (Figure 1c). The MRI scan revealed isointense thickening on T1 weighted fat saturated images (Figure 1d), showing homogenous enhancement on post-contrast T1 weighed images (Figure 1e) in the same region with prominent diffusion restriction (Figure 1f, g). Upper GI endoscopy (Figure 1h) demonstrated a thickened and lobulated appearance of the fundus causing moderate luminal narrowing, however, no ulcerations or mucosal erosions were seen.
(a) Hematoxilin and eosin stain (H&E), 4x Fragmented gastric biopsy shows a cellular fragment, (b) H&E, 10x: Higher magnification of the cellular fragment comprising of high nuclear/cytoplasmic (N/C) ratio cells, (c) immunohistochemistry (IHC), CD45: Atypical lymphoid cells show diffuse membranous expression of CD45, (d) IHC, CD20: Atypical lymphoid cells show diffuse membranous expression of CD20, (e) IHC, Ki-67: High labelling index of Ki-67 expressed by the atypical lymphoid cells.
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Histology on the biopsy acquired reported sheets of atypical lymphoid cells in the subepithelium (Figure 2a), intermediate to large in size, exhibiting moderate nuclear pleomorphism, a high nuclear-cytoplasmic ratio, vesicular chromatin, conspicuous nucleoli and a scant amount of cytoplasm (Figure 2b). On immunohistochemistry, the tumour cells were positive for CD45 (leucocyte common antigen [LCA]) (Figure 2c) and CD20 (Figure 2d) and negative for CK & CD3. Ki-67 labelling index was 90% - 95% (Figure 2e).