Rosai Chapter 16 - Appendix Flashcards
The appendix reaches its maximum diameter by what age?
4 years old
other name of Obliteration of the tip of the Appendix (4):
- Fibrous obliteration
- Neuroma
- Neuroappendicopathy
- Neurogenic appendicitis
Most common abdominal surgical emergency
Acute appendicitis
Earliest gross findings in acute appendicitis
-dullness of the serosal surface with injection of the serosal vessels
Most common complication of acute appendicitis
Perforation
Most helpful in confirming the diagnosis of Crohn disease in the appendix
presence of Extra-appendiceal disease
other name of Enterobius vermicularis (2)
- Pinworms
- Oxyuriasis
Highest prevalence of pinworm infection
-Children and Adolescents
Bacterial infection that is a well-known cause of granulomatous appendicitis
Yersinia (Y. enterocolitica or Y. pseudotuberculosis)
Characteristic histologic features of Yersinia infection (3):
- Epithelioid granulomas with associated prominent lymphoid tissue
- Mural fibrosis
- Transmural lymphoid aggregates
Histologic features that distinguish Sessile Serrated Polyps/Adenomas from Hyperplastic polyps (4):
- Dilated crypts
- Serrations that extend the full length of the gland
- Lateral branching/budding of glands at the base
- “Reverse maturation”
Intestinal-type Adenoma vs. SSP/A & LAMN
-do not show circumferential involvement of the mucosa
Intestinal-type Adenoma
Other name of Goblet Cell Carcinoid (3):
- Goblet cell-type Adenocarcinoid
- Mucinous carcinoid tumor
- Crypt cell carcinoma
Goblet cell carcinoid tumor that give rise to adenocarcinoma, often signet ring cell type or poorly differentiated
Adenocarcinoma ex goblet cell carcinoid
Features indicative of carcinoma in Adenocarcinoma ex goblet cell carcinoid (4):
- Significant nuclear atypia
- Single infiltrating cells
- Loss of mucin production
- increased Ki-67 immunolabeling
Distinct manner of invasion of the appendiceal wall in LAMN
-a broad pushing front with effacement of the muscularis mucosae and mural atrophy, fibrosis, and/or calcification
Features favoring diverticulum over LAMN (3):
- Presence of non-neoplastic epithelium
- Continuity of mural epithelium with that lining the lumen of the lesion
- intact, normal-appearing muscularis propria
Myxoglobulosis is also known as:
“Caviar appendix”
POSITIVE or NEGATIVE
IHCs of Appendiceal mucinous neoplasm and Pseudomyxoma peritonei:
CK20
POSITIVE
POSITIVE or NEGATIVE
IHCs of Appendiceal mucinous neoplasm and Pseudomyxoma peritonei:
CDX2
POSITIVE
POSITIVE or NEGATIVE
IHCs of Appendiceal mucinous neoplasm and Pseudomyxoma peritonei:
MUC2
POSITIVE
POSITIVE or NEGATIVE
IHCs of Appendiceal mucinous neoplasm and Pseudomyxoma peritonei:
CK7
Variably positive
POSITIVE or NEGATIVE
Mutations in appendiceal adenomas, LAMN, and Mucinous adenocarcinoma
KRAS
Positive
POSITIVE or NEGATIVE
Mutations in appendiceal adenomas, LAMN, and Mucinous adenocarcinoma
BRAF
NEGATIVE
POSITIVE or NEGATIVE
Mutations in appendiceal adenomas, LAMN, and Mucinous adenocarcinoma
APC
NEGATIVE
POSITIVE or NEGATIVE
Mutations in appendiceal adenomas, LAMN, and Mucinous adenocarcinoma
MSI
NEGATIVE
Most common type of appendiceal tumor
Well differentiated NETs
Location of great majority of Appendiceal NETs
-tip/distal third
Morphologically, the vast majority of appendiceal NETs
Serotonin-producing Enterochromaffin (EC) cell tumors
POSITIVE or NEGATIVE
IHC of EC cell tumors:
Chromogranin A
Positive
POSITIVE or NEGATIVE
IHC of EC cell tumors:
Synaptophysin
Positive
POSITIVE or NEGATIVE
IHC of EC cell tumors:
Serotonin
Positive
POSITIVE or NEGATIVE
IHC of EC cell tumors:
CDX2
Positive
-marker of midgut derivation
POSITIVE or NEGATIVE
IHC of EC cell tumors:
S100
Positive
-in sustentacular cells
POSITIVE or NEGATIVE
IHC of EC cell tumors:
Ki-67
Positive
-very low (less than 1%)
POSITIVE or NEGATIVE
IHC of EC cell tumors:
Pancytokeratin
Weakly Positive
POSITIVE or NEGATIVE
IHC of EC cell tumors:
CK7
Negative
POSITIVE or NEGATIVE
IHC of EC cell tumors:
CK20
Negative
Formerly known as Tubular Carcinoids
-Enteroglucagon (L) cell NETs
POSITIVE or NEGATIVE
IHC of L cell NETs:
Chromogranin B
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
Synaptophysin
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
Glucagon
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
IgA
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
Pancreatic polypeptide
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
Peptide YY
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
CEA
Positive
POSITIVE or NEGATIVE
IHC of L cell NETs:
Ki-67
Positive
-very low
POSITIVE or NEGATIVE
IHC of L cell NETs:
CK7
Variable
POSITIVE or NEGATIVE
IHC of L cell NETs:
CK20
Variable
POSITIVE or NEGATIVE
IHC of L cell NETs:
Chromogranin A
Negative
Features favoring tubular carcinoids over primary or metastatic adenocarcinoma (3):
- Lack of mitoses and nuclear atypia
- Orderly arrangement
- Origin at the base of the glands of otherwise normal mucosa