Category Archives: Appendix

Appendix Carcinoid Tumors

Appendix Carcinoid Tumors

Gross: tip, < 1 cm; gray or yellow, firm, intramural nodule
Histology:
1) insular (nests)
2) trabecular
3) adenocarcinoid
a) tubular
b) goblet cell (mucicarmine, PAS-D, Alcian Blue)

Treatment:

Appendectomy: ? if < 1cm
Indications for right hemicolectomy:
1. > 2 cm
2. positive margin
3. mesoappendiceal spread

Poor prognosis: >2 cm, mesoappendix invasion
goblet cell carcinoid (mucicarmine, CEA +)

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Mucocele

Mucocele

Mucocele of the Appendix

Definition:
-dilated lumen filled with mucous
Causes of mucocoele:
1. mucinous hyperplasia (looks like hyperplastic polyp)
2. mucinous cystadenoma
3. mucinous cystadenocarcinoma
4. obstruction of the appendix (eg. fecolith, tumour)

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Pseudomyxoma Peritonei

Pseudomyxoma Peritonei

- extravasation of mucin into abdomen
- thought to be clonally derived from associated mucinous tumor, usually of appendix
- also associated ovarian mucinous tumors (thought to be metastases from appendix)

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Appendix Mucinous Cystadenocarcinoma

Appendix Mucinous Cystadenocarcinoma

- like ovarian tumor
- associated with pseudomyxoma peritonei, particularly if ruptures

Gross appearance: resembles cystadenoma

Histology
- complex papillary fronds
- stratification
- destructive invasion wall

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Appendix Mucinous Cystadenoma

Appendix Mucinous Cystadenoma

- intestinal type epithelium with minimal atypia

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Mucinous Hyperplasia

Mucinous Hyperplasia

Also known as hyperplastic polyp

- looks like a colonic hyperplastic polyp

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Simple mucocele

Simple mucocele

- obstructed appendix with intraluminal mucin accumulation

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Mucous Lesions of the Appendix

Mucous Lesions of the Appendix

•    Simple mucocele
•    Hyperplastic polyp / mucinous hyperplasia
•    Mucinous cystadenoma
•    Mucinous cystadenocarcinoma

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Fibrous Obliteration

Fibrous Obliteration

Gross appearance

- firm white tip

Histology

- spindle cells and myxoid component (neural HP)

Immunohistochemistry

S100, chromogranin, NSE

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Enterobius Vermicularis

Enterobius Vermicularis

Clinical presentation

- pinworm, ages 7-11, usu incidental

Histology

- cross section has narrow lateral cuticular alae; causes granulomas

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