Case of a Patient with Epigastric Pain

History:

A 32 years old man presented to his GP with gnawing pain in epigastrium for the last 2 years. Pain tends to be worse at night and is relieved on taking food.

Examination:

The patient was anemic. His physical examination revealed tenderness in the epigastrium. No viscera were palpable.

Laboratory Investigations:

His hemoglobin was 8 g/dL and RBCs were microcytic hypochromic. Endoscopic biopsy revealed a few curved organisms and infiltration by neutrophils in the mucosa (fig. below). Lymphoid follicle formation was also found.

Tasks:

1. What is the differential diagnosis of the above mentioned sign/symptoms?
2. What is etiology and pathogenesis of the disease?
3. Explain in detail the morphological changes seen in the gastric biopsy.
4. What are special techniques used by the pathologists to reach exact type of the diagnosis?
5. Describe the possible complications caused by this disease.