Flask shaped undermined ulcers in rectosigmoid area are seen in
Most amoebic ulcers occur in the rectosigmoid. On sigmoidoscopy shallow skip lesions and 'flaskshaped' or 'collar-stud' undermined ulcers may be seen and can be biopsied or scrapings can be taken along with mucus for immediate microscopic examination. The presence of trophozoites distinguishes the condition from ulcerative colitis.Ref: Bailey and Love 27e pg: 58
Amoebiasis
Typhoid
Tuberculosis
Hydatid disease
General surgery