Anus & Peritoneum

Question 1

What types of tumors can be found in the anus?

Answer 1

Above pectinate line:

-adenocarcinoma

Below the pectinate line:

• squamous cell carcinoma
• basal cell carcinoma
• melanoma

Transitional epithelium around pecinate line:

-Mixed

Question 2

What are hemorrhoids and how do they present?

(types)

Answer 2

Caused by persistantly elevated BP in rectal venous plexus

Internal:

-originate from mucosa above pectonate line

-superior

• bright red blood in stool
• painless

External:

• originate from skin below pectinate line
• painful

Question 3

What is the appendix?

Answer 3

A true divertiuculum located at the cecum

Question 4

What causes acute appendicitis?

Answer 4

Obstruction of the appendiceal lumen ->

• bacterial overgrowth -> inflammation
• or
• increased intraluminal pressure -> compromised venous outflow

Causes of obstruction:

• fecalith
• gallstone
• tumor
• pin worms (Enterobius vermicularis)

Question 5

How does appendicitis present?

Answer 5

Migrating abdominal pain:

• starts as epigastric pain -> migrates to McBurney’s point in RLQ
• nausea/vomiting
• low-grade fever
• mild leukocytosis

Question 6

What is the epidemiology of appendicitis?

Answer 6

most commonly presents in:

• adolescents and young adults
• slight male predominance
• 7% lifetime risk

Question 7

What tumors present in the appendix?

Answer 7

• well differentiated neuroendocrine tumor (carcinoid) most common
• adenomas/adenocarinomas
• mucinous cystadenoma/cystadenocarinoma

Question 8

What condition is associated with appendiceal mucinous cystadenocarcinomas?

Answer 8

Pseudomyxoma peritonei:

-intraperitoneal accumulation of mucinous ascites

Question 9

What are causes of peritonitis?

Answer 9

Bacterial or chemical invasion from:

• leakage of bile/pancreatic enzymes (sterile peritonitis)
• rupture of biliary system (usally followed by bacterial infection)
• actue hemorrhagic pancreatitis (leakage of enzymes -> fat necrosis of bowel w/ possible rupture)
• foriegn bodies -> FB granulomas

-endometriosis -> hemorrhage

-ruptured ovarian cyst -> release of irritants

Question 10

What is spontaneous bacterial peritonitis?

What conditions is it associated with?

Answer 10

Primary bacterial peritonitis; occurs with no obvious source of contamination

Associated with:

• cirrhosis/ascites (most common)
• nephrotic syndrome in children

Question 11

What is sclerosing retroperitonitis?

Answer 11

Idiopathic retroperitoneal fibrosis/Ormond disease:

• attributed to IgG4-related disease
• inflammation -> fibrosis of retroperitoneum
• impinges on bilateral ureters and aorta

Presents as back and abominal pain

• ARF
• hydronephrosis
• elevated CRP and ESR

Question 12

What tumors present in the peritoneum?

Answer 12

Primary (rare):

• mesothelioma
• desmoplastic small round cell tumor

Secondary (more common):

• metastasis to peritoneum -> peritoneal carcinomatosis
• metastasis of appendiceal mucinous carcinoma -> pseudomyxoma peritonei