This document describes different types of colon polyps and tumors. It discusses non-neoplastic polyps such as hyperplastic, hamartomatous, inflammatory, and lymphoid polyps. It also covers neoplastic polyps including tubular, villous, and tubulovillous adenomas, which have the potential for malignant change. Various benign and malignant colon tumors are also outlined such as leiomyomas, leiomyosarcomas, and colorectal carcinoma, which is the most common form of visceral cancer. The document provides details on the characteristics, etiology, gross anatomy, microscopic features, and clinical presentation of these colon polyps and tumors.

1. TUMORS OF COLON

2. • COLORECTAL POLYPS:
o any growth or mass protruding from mucus
membrane into lumen.
o Large intestine > small intestine
o Recto - Sigmoid colon > proximal colon
o Classification :
1. Non – neoplastic
2. Neoplastic

3. Non – neoplastic polyps:
Types:
1. hyperplastic / metplastic polyps
2. Hamartomatous polyps
3. Inflammatory polyps
4. Lymphoid polyps

4. HYPERPLASTIC POLYPS:
• Most common
• Rectosigmoid
• Any age. Common: 60 – 70 yrs
• Areas of hyperplasia and areas of metaplasia
present
• Polyp + adenoma = malignant; polyp = benign
G / A:
• Multiple
• Sessile
• Smooth surface
• Small : < 0.5 cm
M / E:
• Long and cystically dilated glands lined by normal
epithelium

6. HAMARTOMATOUS POLYPS :
• Tumor like lesions containing abnormal mixture of
cells indegenous to that part.
• 2 types:
1. Peutz – Jeghers Polyps and Polyposis:
• Autosomal dominant defect
• Character: hamartomatous intestinal polyposis
with melanotic pigmentation on lips, mouth and
genitalia
G / A:
• Variable size. Common : large
• Multiple
• Pedunculated
M / E:

8. 2. Juvenile / retention polyps:
• Hamartomatous polyps occuring in children below
5 years
• Solitary
• Common in rectum
G / A:
• Spherical
• smooth surfaced
• Pedunculated
• 2 cm = dm
M / E:
• Cystically dilated glands containing mucus
• Normal mucus secreting epithelial cell lining
• If chronic ulceration of surface is present then
stroma shows inflammatory cell infiltrates.

10. INFLAMMATORY POLYPS:
• Re-epithelization of undermined ulcers and
overhanging margins in inflammatory bowel
diseases like ulcerative colitis and Crohn’s
disease.
G / A:
1. Multiple
2. Cylindrical to rounded
3. Minute nodules – several centimeters
M / E:
• Centre of the polyp contains connective tissue
core that contains some inflammatory cell
infiltrates and are covered by thin layer of
regenerating epithelial cells and cystically

12. Lymphoid polyps:
• Reactive hyperplasia of lymphoid tissues.
• Prominent in rectum and terminal ileum
• Also called rectal tonsils
G / A:
• Solitary / multiple
• Tiny
• Elevated lesions
M / E:
• Prominent lymphoid follicles with germinal
centres located in mucosa and submucosa
• Inflammed epithelial covering

14.  Neoplastic polyps:
• Colorectal adenomas which have potential for
malignant change
• 3 main varieties
1. Tubular
2. Villous
3. Tubulovillous

15. TUBULAR ADENOMA / ADENOMATOUS
POLYP:
• most common
• > 30 years
• Male > female
• Common in distal colon and rectum
• Asymptomatic / rectal bleeding
G / A:
• single or multiple
• sessile or pedunculated
• less than 1 cm or more
• large, spherical masses with an irregular

17. M / E:
• Branching tubules embedded in the lamina
propria.
• The lining epithelial cells are of large intestinal
type with diminished mucus secreting capacity,
large nuclei and increased mitotic activity.
• Variable degree of cytologic atypia ranging from
‘carcinoma in situ’ to frank adenocarcinoma

18. VILLOUS ADENOMA / VILLOUS PAPILLOMA:
• Less common.
• >60 years
• Both men and women.
• Often in the distal colon and rectum.
• invariably symptomatic
• rectal bleeding, diarrhoea and mucus being the
common features.
• The presence of severe atypia, carcinoma in
situ and invasive carcinoma are seen more
frequently.

19. G / A:
• round to oval exophytic masses
• sessile
• 1 to 10 cm or more in diameter.
• surface may be haemorrhagic or ulcerated.
M / E:
• many slender, finger-like villi, which appear to
arise directly from the area of muscularis
mucosae.
• Each of the papillae has fibrovascular stromal
core that is covered by epithelial cells varying
from apparently benign to anaplastic cells.

21. TUBULOVILLOUS ADENOMA / PAPILLARY
ADENOMA / VILLOGLANDULAR ADENOMA:
• intermediate form of pattern between tubular
adenoma and villous adenoma
• most common
• > 30 years
• Male > female
• Common in distal colon and rectum
• Asymptomatic / rectal bleeding

22. G / A:
• single or multiple
• sessile or pedunculated
• less than 1 cm or more
• large, spherical masses with an irregular surface.
M / E:
• Branching tubules embedded in the lamina
propria.
• The lining epithelial cells are of large intestinal type
with diminished mucus secreting capacity, large
nuclei and increased mitotic activity.
• Variable degree of cytologic atypia ranging from
‘carcinoma in situ’ to frank adenocarcinoma

24.  OTHER BENIGN TUMORS ARE:
1. Leiomyomas
2. Leiomyoblastoma
3. Neurilemmoma
4. lipoma
5. vascular tumours - haemangioma,
lymphangioma

25. MALIGNANT TUMORS :
1. Colorectal Carcinoma
2. leiomyosarcoma
3. malignant lymphoma
4. Hindgut carcinoids may occur in the rectum
and colon

26. COLORECTAL CARCINOMA:
• commonest form of visceral cancer
• Age : 60 years and above
• Common in males than females
ETIOLOGY:
1. Geographic variations
2. Dietary factors.
3. Adenoma-carcinoma sequence.
4. Hereditary non-polyposis colonic cancer
(HNPCC or Lynch syndrome)
5. Other factors

28. GROSS ANATOMY:
• Right-sided colonic growths:
• large
• cauliflower-like, soft and friable masses
projecting into the lumen (fungating polypoid
carcinoma).
• Left-sided colonic growths:
• napkin-ring configuration - they encircle the
bowel wall circumferentially with increased
fibrous tissue forming annular ring
• central ulceration on the surface with slightly
elevated margins (carcinomatous ulcers).
• However, early lesion in left as well as right
colon are small, button-like areas of elevation.

30. Microscopically:
• the appearance of right and left-sided growths is
similar.
• adenocarcinomas of varying grades of
differentiation, most are mucin-secreting colloid
carcinomas while some are uncommon microscopic
patterns like undifferentiated carcinoma, signet-ring
cell carcinoma, and adenosquamous carcinomas
seen in more distal colon near the anus.
• The histologic grades indicating the degree of
differentiation are: well-differentiated, moderately
differentiated and poorly-differentiated

32. SPREAD:
1. Direct spread
2. Lymphatic spread
3. Haematogenous spread
CLINICAL FEATURES:
1. Melaena
2. Change in bowel habits, more often in left-
sided growth
3. Cachexia
4. Anorexia
5. Anaemia, weakness, malaise.