Discussion
We report a rare case of laparoscopically resected gastric
adenocarcinoma with concurrent lanthanum deposition. In this case, we
chose surgical resection because of the ambiguous boundary between
malignant tissue and mucosal changes with lanthanum deposition.
There are a few reports of surgically resected gastric cancer with
lanthanum deposition, as summarized in Table 1.2,12Yabuki et al. reported a summary of three patients with gastric cancer
accompanied by lanthanum deposition who underwent surgical
resection.11 They reported that the duration of
lanthanum administration ranged from 3 to 36 months, and the depth of
cancer was the entire submucosa (range: 1.5–5 mm). Lanthanum deposition
was identified in the regional lymph nodes to some degree in all three
cases. These findings support the hypothesis that lanthanum
malabsorption in the gastric mucosa leads to other lymph nodes via
lymphatic flow. Tonooka et al. reported a case of multiple but early
gastric cancers in a patient with lanthanum deposition who underwent
subtotal gastrectomy after 7 months of drug use.12 In
this case, many macrophages with lanthanum deposits accumulated in the
lamina propria of the gastric wall and tumors, which was confirmed by
scanning electron microscopy-energy-dispersive X-ray spectroscopy
(SEM-ESD). They also showed intestinal metaplasia associated with
lanthanum deposition and considered that altered tight junction proteins
may lead to its permeability, possibly resulting in lanthanum
deposition. Our case showed mucosal atrophy and metaplasia, including a
cancerous lesion at the gastric antrum, with CD68-positive macrophages
containing lanthanum deposits, which were also identified in regional
lymph nodes.
In gastric adenocarcinoma concurrent with lanthanum deposition, the
findings of lanthanum deposition by endoscopy are occasionally similar
to carcinoma, and it can be difficult to mark the boundary of the
neoplasm and lesions. The findings of lanthanum deposition have been
usually described as shiny, bright white, and of varied sizes and
shapes, from small and flat to elevated plaques.9Gastric carcinoma is also known to show various findings with endoscopy.
In previous reports, early gastric cancer with lanthanum deposition was
observed as a depressed area surrounded by annular whitish
lanthanum-deposited mucosa8,13 and resected by
endoscopy. Yabuki et al. summarized the cases of three patients with
concurrent gastric cancer who received laparoscopic distal gastrectomy,
but the endoscopic findings showed a clear boundary between malignant
tissue and the surrounding mucosa with lanthanum
deposition.11 Tonooka et al. also reported concurrent
gastric cancer with lanthanum deposition in patients receiving subtotal
gastrectomy, but they did not refer to the endoscopic
findings.12 The usefulness of magnified imaging using
NBI was recently reported, and it shows irregular vascular and pit
structures of malignant tissues.13 However, in this
case, the carcinoma was detected within multiple reddish granular areas
with lanthanum deposition without any specific malignant findings with
NBI, and it was difficult to find the boundary between the neoplasm and
lanthanum deposition. Therefore, we considered the possibility of
non-curative resection with endoscopy and other lurking regions, and the
carcinoma was surgically resected. Furthermore, using laparoscopy made
it possible to observe the whole serous membrane of the stomach, nearby
lymph nodes, and other organs in detail.
The relationship between malignancy and lanthanum deposition in gastric
cancer concurrent with lanthanum deposition is unknown. Yabuki et al.
examined the effect of oral administration of lanthanum carbonate on
gastric mucosa in a rat model.11 They showed that it
caused various histologic alterations such as glandular atrophy, the
proliferation of mucous neck cells, and intestinal metaplasia, and
concluded that these mucosal injuries, named lanthanum gastropathy,
could potentially induce abnormal cell proliferation or neoplastic
lesions. In sequential changes of the gastric epithelium due to
lanthanum gastropathy, it becomes difficult to identify the boundary
between the neoplasm and mucosal changes without malignancy, and
surgical resection is recommended in such cases.
We present a rare case of gastric adenocarcinoma concurrent with
lanthanum deposition in a patient who underwent laparoscopic distal
gastrectomy due to ambiguous borders. In our case, it is difficult to
mark the border between the neoplasm and lesions due to lanthanum
deposition, and we performed surgical resection to secure a curative
margin. The clinical significance and relationship between neoplasm and
lanthanum deposition have been suggested, but enough evidence has not
been reported. Our results add to this growing body of data and will aid
in clarifying this relationship.
Table.1 Summary of surgically resected gastric cancer with lanthanum
deposition, including this case