Keywords
Gastric carcinoma - granulomas - tuberculosis
Introduction
Isolated gastric tuberculosis (TB), without evidence of pulmonary or other gastrointestinal
(GI) involvement, is extremely rare, even in parts of the world where intestinal TB
is common. The incidence of gastric TB, whether as a primary or secondary infection,
is found in only 0.03%–0.21% of all routine autopsies, and in 0.3%–2.3% of autopsies
of patients with known concurrent pulmonary TB.[1]
[2]
Case Summary
A 40-year-old female, hypothyroid, presented with dyspepsia, weight loss, fever for
2 months. She had a history of pulmonary TB 6 years back and treated by directly observed
treatment short-course Revised National TB Control Program regieme. Clinical examination
was unremarkable. All baseline investigations including complete blood count, blood
chemistry, chest X-ray, ultrasound abdomen were normal. A 4 weeks Proton-pump inhibitor
therapy could not relieve her symptoms. Upper GI tract (GIT) screening was done which
showed an irregular ulcer measuring 1 cm at incisura and another circumscribed ulcer
about 5 mm at the junction of body and antrum. Histopathology revealed mononuclear
infiltrate with doubtful granuloma formation. Repeat endoscopy after a month revealed
an infiltrative growth involving lower two-thirds of the stomach [Figure 1]. An impression of carcinoma stomach was made by the endoscopist, but histopathology
revealed chronic inflammatory granulation tissue with many acute Inflammatory cells
with occasional cluster of epitheloid cells in lamina propria. Contrast-enhanced computed
tomography abdomen showed a Circumferential mural thickening at the antropyloric region
of the stomach with the ill-defined fat plane, with multiple peripyloric lymph nodes
[Figure 2]. Patient was referred to a surgical oncologist who operated her. Distal subtotal
gastrectomy with Billroth II reconstruction was done.
Figure 1: Endoscopy showing a slough, altered blood, ulcer
Figure 2: Contrast‑enhanced computed tomography abdomen showing the thickened antropyloric
junction
Intra operative findings
-
Diffuse growth at incisura angularis with the involvement of serosa
-
Ascitis
-
Enlarged infrapyloric, pre-pyloric group of lymph nodes.
The specimen on histopathology revealed granulomas formation and was referred by oncology
section to Infectious diseases department for review.
The patient was evaluated for concomitant TB. Chest X-ray was normal, sputum and urine
for acid-fast bacteria were negative. High erythrocyte sedimentation rate of 60 mm/h
with mild anemia of chronic disease was found. Mantoux was positive (20 mm).
Review histopathology of the specimen showed chronic inflammatory infiltrate comprising
mostly lymphocytes forming follicles at places. Lymphnodes showed epithelioid granulomas
with Langhans type giant cells. The patient was put on anti-tubercular therapy. A
basket of four drugs for 2 months and two drugs for next 4 months was given. Ascitis
resolved completely with resolution of pre-pyloric lymph nodes. The weight and general
well-being of the patient were improved at 6 month follow-up with check ultrasound
revealing a normal picture and check endoscopy showing a normal stomach with evidence
of distal gastrectomy.
Discussion
TB can involve any part of GIT from mouth to anus, the peritoneum, and the pancreatobiliary
system. Gastric TB is a rare condition. The relative rarity of gastric TB can be attributed
to the:
-
Bactericidal properties of gastric acid
-
The scarcity of lymphoid tissue in the gastric wall
-
The continuous motor activity of the stomach.[1]
Almost always located in the antrum or prepyloric region. Gastric TB normally occurs
secondarily to pulmonary TB or another organic infection. It has been postulated that
the causes of isolated primary gastric TB may include the ingestion of unpasteurized
milk infected with bovine TB or a severely immunocompromised condition.[2] Secondary TB occurs when patients with active pulmonary TB swallow tuberculous bacilli.
Other possible mechanisms include direct mucosal invasion, hematogenous spread, extension
from adjacent structures, and superinfection of a pre-existing ulcer or malignancy.[2]
[3] In cases of gastric TB, nodal involvement is usually extensive. Route of spread
is thought to be the celiac lymph nodes. Abdominal pain is the symptom most commonly
associated with GI TB. Other symptoms, including diarrhea, fever, anorexia, weight
loss, and constipation, are usually observed, but hematemesis is extremely rare.[1]
[4]
[5] It has also been suggested that, although intestinal TB results in increased capillary
vascularity, small arteries undergo obliterative endarteritis in TB. This would explain
the rarity of bleeding in such cases.[6] Endoscopy plays an important role in diagnosis. Single and multiple ulcers have
been associated with this disease, as have hypertrophic nodular lesions surrounding
a stenotic pyloric channel.[1] The associated ulcers are typically found to be irregular with a necrotic base,
which may extend into the perforation. A definitive diagnosis essentially relies on
a histological approach, normally involving the Ziehl–Neelsen staining for acid-fast
bacilli and culturing. Histopathological findings of caseating epithelioid cell granulomas
are very helpful. However, diagnosis cannot always be made from the specimens taken
by endoscopy. Granulomas, whether caseous or noncaseous, are frequently found to be
negative on endoscopic biopsies.[7] This may be the reason for the paucity of diagnosis on endoscopic biopsy of our
patient. One of the reasons for this is the very low diagnostic yield of endoscopic
biopsy specimens. In such cases, tumors that do not originate from the mucosa, such
as GI stromal tumor and lymphoma should generally be considered. Polymerase chain
reaction testing of biopsy specimens may facilitate diagnosis and allow the exclusion
of Crohn’s disease with a 100% specificity and a sensitivity of 27%–75%. Radiological
investigations including computed tomography are sensitive in detecting the local
burden of pathology, i.e., the extent of involvement, surrounding infiltration as
well as complications like perforation. However, most of the radiological features
in these cases are indistinguishable from primary malignant lesions of upper GI and
therefore warrant confirmation by histopathology.
Conclusion
Although gastric TB is a rare condition, in patients presenting with endoscopic evidence
of diffuse chronic inflammatory activity, the possibility of gastric TB should be
considered, particularly in areas in which TB maintains endemicity.[3] TB is a great mimicker. It is also a disease that can be easily controlled and treated.
Clinicians need to be aware of the myriad manifestations of TB and resist the temptation
of premature diagnostic closure. Due to inaccurate clinical diagnoses, most patients
end up requiring surgical intervention, only after which is gastric TB diagnosed.
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