Ovarian Mucinous Lesions: Common Diagnostic Dilemmas

Home , Carcinoma, Cystadenoma, Krukenberg tumor, Mucinous cystadenoma, Pseudomyxoma peritonei

5/25/2013

Ovarian mucinous lesions

• Intestinal or usual type Ovarian mucinous lesions: Common diagnostic dilemmas • Seromucinous (Endocervical mucinous or Mullerian mucinous) type Karuna Garg, MD University of California San Francisco

Ovarian mucinous lesions: problematic issues • Mucinous cystadenoma versus borderline tumor • Mucinous borderline tumor versus carcinoma Mucinous cystadenoma versus • Primary mucinous tumors versus metastasis borderline tumor • Pseudomyxoma peritonei – site of origin, classification and clinical outcomes • Effective handling of mucinous ovarian lesions at frozen section • Mural nodules

1 5/25/2013

Mucinous cystadenoma versus borderline tumor Mucinous cystadenoma versus borderline tumor

Significance Assess for epithelial proliferation Borderline tumors are usually staged. • Sample well • If less than 10% - cystadenoma with focal epithelial atypia/proliferation • Clinical outcome similar to cystadenoma • If >10% - borderline tumor

Mucinous cystadenoma Mucinous cystadenofibroma

2 5/25/2013

Mucinous cystadenofibroma Mucinous cystadenoma with Brenner tumor

Mucinous cystadenofibroma with focal epithelial proliferation Mucinous cystadenofibroma with focal epithelial proliferation

3 5/25/2013

Mucinous borderline tumor

Mucinous borderline tumor versus carcinoma

4 5/25/2013

Mucinous borderline tumor versus carcinoma Mucinous borderline tumor

Significance • Microinvasion - Carcinomas always staged • Intraepithelial carcinoma - Small risk of extra-ovarian disease

- Mucinous borderline tumors are benign and should be stage 1A (if considering an advanced stage borderline tumor or borderline tumor with implants-exclude metastasis)

Mucinous borderline tumor with microinvasion Microscopic: Mucinous borderline tumor with Mucinous borderline tumor microinvasion

Microinvasion • No single invasive focus should measure >5 mm or 10 mm2 • Multiple foci can occur • Prognosis similar to borderline tumors (one recent study shows higher risk of recurrence)

5 5/25/2013

Mucinous borderline tumor with microinvasion Mucinous borderline tumor

Intraepithelial carcinoma • High grade nuclear atypia • Prognosis similar to borderline tumors (one recent study suggests higher risk of recurrence)

Mucinous borderline tumor with intraepithelial carcinoma Mucinous borderline tumor with intraepithelial carcinoma Microscopic: Mucinous borderline tumor with intraepithelial carcinoma

6 5/25/2013

Ovarian mucinous carcinoma: expansile invasion Microscopic: Primary mucinous carcinoma Ovarian mucinous carcinoma

• Unequivocal invasion >5 mm (10 mm 2) • Two patterns of invasion: - Expansile (confluent cribriform/glandular pattern) more common - Infiltrative (worse prognosis) (should exclude metastasis)

Ovarian mucinous carcinoma: expansile invasion Ovarian mucinous carcinoma: expansile invasion Microscopic: Primary mucinous carcinoma

7 5/25/2013

Ovarian mucinous carcinoma: destructive stromal invasion Immunophenotype of primary ovarian mucinous tumors • CK7++ CK7>>CK20 • CK20+(83%) • CDX2+ (40%-less frequently positive in primary ovarian mucinous tumors) • PAX-8+(50%) • ER/PR- • WT1-

Immunophenotype of primary ovarian mucinous tumors

Primary ovarian Tumor type mucinous tumors Primary versus metastatic (n= 42) CK7+/CDX2 - 25 (60%) CK7+/CDX2+ 15 (36%) mucinous neoplasms of the ovary CK7 -/CDX2+ 2 (5%) CK7 -/CDX2- 0 ( -) CK7+/CK20 - 7 (17%) CK7+/CK20+ 33 (79%) CK7 -/CK20+ 2 (5%) CK7 -/CK20- 0 ( -)

Vang, et al. Mod Pathol 2006

8 5/25/2013

Primary versus metastasis Ovarian mucinous carcinoma

• Can be challenging • Uncommon • Metastatic mucinous carcinomas to the ovary can be • <3% of all ovarian carcinomas highly deceptive • Predominantly stage 1 • Sometimes metastatic involvement of the ovary is the primary presentation of a mucinous tumor • Extra-ovarian disease rare without clinical evidence of an extra-ovarian lesion • Immunohistochemistry of limited help

Ovarian mucinous carcinoma Ovarian mucinous carcinoma

• Metastatic mucinous carcinomas are more • 44 cases of advanced stage mucinous common carcinomas • Metastatic mucinous carcinomas can simulate • 61% reclassified as likely metastasis ovarian mucinous carcinoma, borderline • True advanced stage primary ovarian tumor or cystadenoma by radiology and mucinous carcinomas rare (0.5-1.5%) pathology • Advanced stage ovarian mucinous carcinomas highly lethal and survival shorter than serous

Zaino RJ, et al. Cancer 2011

9 5/25/2013

HER2 in ovarian mucinous carcinomas Primary versus metastasis

• Low response rates to carbotaxol Significance • Her2 amplification in 18% mucinous - Prognosis carcinomas and borderline tumors - Therapy • No association with prognosis • Patients may respond to trastuzumab therapy

McAlpine et al, BMC Cancer 2009

Primary versus metastasis: prognosis 5 year survival: Primary versus metastasis: therapy

• Surgery - Primary ovarian cancer: comprehensive surgical staging and debulking - Metastasis: No staging

FIG. 10 . Survival analysis of ovarian mucinous tumors. There is a statistically significant difference in survival between atypical proliferative • tumors (with and without microinvasion), primary mucinous carcinomas, and metastatic carcinomas (p = 0.0001, log rank test). Chemotherapy: Different agents (move

Evaluation of Diagnostic Criteria and Behavior of Ovarian Intestinal-Type Mucinous Tumors: Atypical Proliferative (Borderline) Tumors and Intraepithelial, Microinvasive, Invasive, and Metastatic Carcinomas. toward treating mucinous tumors by histology Riopel, Maureen; Ronnett, Brigitte; Kurman, Robert American Journal of Surgical Pathology. 23(6):617-635, June 1999. rather than site of origin)

10 5/25/2013

Primary versus metastasis Primary versus metastasis

Gross features Primary Metastasis Gross algorithm: Laterality Unilateral Bilateral -Bilateral tumors of any size, unilateral <13 cm: Metastatic Size >10 cm <10 cm -Unilateral > 13 cm: Primary >12 cm <12 cm Surface Absent Present involvement Stage Usually stage I Advanced stage Application of this algorithm correctly identified 98% of primary tumors and 82% metastases

Common exceptions: Colorectal and endocervical carcinomas

Lee et al, Am J Surg Pathol 2003 Seidman et al, Am J Surg Pathol 2003 Yemelyanova et al, Am J Surg Pathol 2008

Primary versus metastasis: pitfalls Primary versus metastasis

Gross: Microscopic features

Metastatic mucinous tumors can be Primary Metastasis - Unilateral Pattern of growth Expansile Nodular - Large Destructive stromal No Yes invasion - Grossly multicystic Ovarian hilar No Yes - Smooth surface involvement Lymphovascular No Yes invasion Microscopic surface No Yes mucin Signet ring cells No Yes/No Pseudomyxoma No Yes peritonei and ovarii

11 5/25/2013

Metastatic colon carcinoma: Nodular, desmoplasia, infiltrative growth pattern Metastatic colon carcinoma: Surface involvement

Metastatic gastric carcinoma: Signet ring cells Metastatic colon carcinoma: Lymphovascular invasion

12 5/25/2013

Metastatic pancreatic carcinoma - mimicking mucinous cystadenoma Primary versus metastasis: pitfalls

Microscopic: “Maturation phenomenon” Metastatic mucinous carcinomas can simulate - Mucinous cystadenoma - Borderline mucinous tumor - Borderline mucinous tumor with intraepithelial carcinoma - Borderline mucinous tumor with microinvasion

Metastatic endocervical adenocarcinoma – mimicking mucinous borderline tumor Primary versus metastasis

• Heterogeneous • Highly differentiated areas adjacent to malignant areas • Look for foci that may be suggestive of metastasis • Consider submitting 2 sections per cm in difficult cases Sampling is key!

13 5/25/2013

Pseudomyxoma peritonei (PMP)

• Clinical entity • Abundant extracellular peritoneal mucin Pseudomyxoma peritonei • May or may not contain epithelial cells • Associated with a heterogeneous group of pathologic lesions

Pseudomyxoma peritonei (PMP) Pseudomyxoma peritonei (PMP)

DPAM (Disseminated PMCA (Peritoneal mucinous Two broad categories: peritoneal adenomucinosis) carcinomatosis) Cellularity Scant Moderate to abundant 1. Low grade: Disseminated peritoneal Cytologic atypia Minimal Moderate to marked adenomucinosis (DPAM) Mitotic activity Rare Occasional to abundant Lymph node involvement Rare Frequent Parenchyma organ Rare Frequent involvement 2. High grade: Peritoneal mucinous Site of origin Appendix Appendix/colon - Cystadenoma - Carcinoma carcinomatosis (PMCA) -Hyperplastic polyp - Villous adenoma 5 and 10 year survival 75% and 68% 14% and 3%

Ronnett et al, Am J Surg Pathol 1995 Ronnett et al, Cancer 2001

14 5/25/2013

Pseudomyxoma peritonei (no epithelium) Pseudomyxoma peritonei (PMP)

Problems: 1. Pathologic terminology - Lack of consensus - Disseminated peritoneal adenomucinosis (DPAM) = Well differentiated adenocarcinoma = Low grade appendiceal mucinous neoplasm (LAMN) = Pseudomyxoma peritonei

2. PMP frequently involves ovaries, but virtually never originates there

Pseudomyxoma peritonei: Low grade epithelium Pseudomyxoma peritonei: Low grade epithelium

15 5/25/2013

Pseudomyxoma peritonei: High grade epithelium with signet ring cells Pseudomyxoma peritonei (PMP)

Take home message: - Most cases of PMP are of appendiceal or intestinal origin - Ovarian involvement is secondary

Exception: Mucinous tumors arising in ovarian teratomas

Ovarian mucinous tumors associated with mature cystic Ovarian mucinous tumors associated with mature cystic teratomas teratomas

- 2-11% of mature cystic teratomas Patient with pseudomyxoma peritonei, unilateral low grade - Teratoma component may be focal mucinous tumor and no identifiable GI primary? 1. Mucinous cystadenoma 2. Mucinous borderline tumor 3. Appendiceal type low grade mucinous neoplasm 4. Goblet cell carcinoid 5. Mucinous adenocarcinoma

- Variable immunophenotypes (may stain like a lower GI primary) - May closely resemble appendiceal mucinous tumors - Can lead to pseudomyxoma peritonei (PMP) and pseudomyxoma Additional sections from the ovary to identify a teratomatous ovarii component may be helpful!

Vang et al, Am J Surg Pathol 2007 McKenney et al, Am J Surg Pathol 2008

16 5/25/2013

Teratoma (caseous material and hair)

Microscopic: Ovarian mucinous tumors associated with mature cystic teratomas

17 5/25/2013

Appendiceal mucinous neoplasms Primary sites for mucinous neoplasms involving ovary 1. Mucinous adenoma: 1. Appendix - Low grade, confined to appendix 2. Large intestine 2. Low grade mucinous neoplasm with low risk of recurrence: 3. Pancreas - Low grade, extra-appendiceal acellular mucin, no invasion 4. Gallbladder 3. Low grade mucinous neoplasm with high risk of recurrence: 5. Stomach - Low grade, extra-appendiceal neoplastic epithelium, no invasion 6. Cervix 4. Mucinous adenocarcinoma: 7. Urachus - High grade, complex, invasive 8. Lung 9. Others

Pai et al, Am J Surg Pathol 2009

Low grade appendiceal mucinous neoplasms Low grade appendiceal mucinous neoplasms involving ovary Gross: Appendix: - Bilateral (but may be unilateral) - Low grade cytology - Large - Appearance similar to mucinous adenoma but - Multilocular - Surface involvement with extra-appendiceal mucin (with or without - Gross mucin neoplastic epithelium) Microscopic: - Tall columnar cells with mucin - Submit entire appendix - Minimal cytologic atypia and mitotic activity - Mucin dissection into ovarian stroma (pseudomyxoma ovarii)

Can mimic ovarian mucinous cystadenoma or borderline tumor

18 5/25/2013

Low grade appendiceal mucinous neoplasm involving ovary Low grade appendiceal mucinous neoplasms involving ovary: distinction from primary

• Bilateral • Surface involvement • Pseudomyxoma peritonei • Pseudomyxoma ovarii • CK20>>CK7 • More CDX2

Low grade appendiceal mucinous neoplasm involving ovary: surface mucin Low grade appendiceal mucinous neoplasm involving ovary

19 5/25/2013

Low grade appendiceal mucinous neoplasm involving ovary: pseudomyxoma ovarii Low grade appendiceal mucinous neoplasm

Low grade appendiceal mucinous neoplasm CK20 CK7

20 5/25/2013

Intestinal adenocarcinoma metastatic to ovary: Intestinal adenocarcinoma metastatic to ovary distinction from primary • Predominantly large intestine (colorectal) • Small, bilateral with surface involvement • But frequently large, unilateral with smooth surface • Most common metastatic tumor involving • Solid and cystic ovary • Can mimic endometrioid and mucinous carcinomas of the ovary • May present with elevated CA-125 • May first present with an ovarian mass

Lash RH and Hart WR. Am J Surg Pathol 1987

Intestinal adenocarcinoma metastatic to ovary: Immunohistochemistry distinction from primary

• Nodular • CK20 >> CK7 • Confluent/cribriform glandular • CDX2: • “Garlanding” - Not specific but typically more compared to • Dirty necrosis ovarian primary • Infiltrative growth and desmoplasia (often focal) • Lymphovascular invasion • High grade cytology- but may have foci of extremely well differentiated mucinous epithelium

Lash RH and Hart WR. Am J Surg Pathol 1987

21 5/25/2013

Metastatic colon carcinoma: Nodular, desmoplasia, infiltrative growth pattern Metastatic colon carcinoma

Metastatic colon carcinoma Metastatic colon carcinoma

22 5/25/2013

CK20 CK7 CDX2

Pancreatobiliary carcinoma: distinction from ovarian Pancreatobiliary system primary

• Ovarian tumor can present first or synchronously with the • Bilaterality (89%) pancreatic tumor • • Can simulate an ovarian primary grossly and microscopically Small size (mean size <12 cm) • Frequently unilateral, cystic and large, with smooth surface • Multinodular growth (63%) • Microscopically can simulate mucinous cystadenomas or • Surface implants borderline tumors (can show mixture of benign to malignant epithelium) • Focal infiltrative invasion • Presence of extra-ovarian disease

Meriden Z, et al. Am J Surg Pathol 2011 Meriden Z, et al. Am J Surg Pathol 2011

23 5/25/2013

Immunohistochemistry DPC4/SMAD4

• CK7>>CK20 • SMAD4 (DPC4) somatic alterations in 55% of pancreatic cancers and 10-35% of colon carcinomas • Loss of SMAD4 (DPC4) • Immunohistochemical loss of expression • Positive for CA-125 Pancreatic carcinoma (46%-61%) Colon carcinoma (11%) Ovarian mucinous carcinoma (0%)

-Loss of DPC4 expression is very helpful to make a diagnosis of pancreatobilary carcinoma -But retained DPC4 expression does not exclude pancreatobiliary origin

Ji et al, Int J Gynecol Pathol 2002 Meriden et al, Am J Surg Pathol 2011

Metastatic pancreatic carcinoma Metastatic pancreatic carcinoma

24 5/25/2013

Metastatic pancreatic carcinoma Metastatic pancreatic carcinoma

Metastatic pancreatic carcinoma: Omentum Metastatic pancreatic carcinoma: Loss of SMAD4/DPC4

25 5/25/2013

Metastatic pancreatic carcinoma: Loss of SMAD4/DPC4 Krukenberg tumor of the ovary

• Signet ring cells 10% • Tubular type • Average age 45 years

• Most common primary sites include (may be occult): - Stomach - Appendix - Colon/rectum - Gall bladder/biliary system - Breast

Ovarian primary (extremely rare and diagnosis of exclusion!)

Metastatic gastric carcinoma Krukenberg tumor of the ovary

Krukenberg Tumors of the Ovary: A Clinicopathologic Analysis of 120 Cases With Emphasis on Their Variable Pathologic Manifestations. Kiyokawa, Takako; Young, Robert; Scully, Robert

American Journal of Surgical Pathology. 30(3):277-299, March 2006. DOI: 10.1097/01.pas.0000190787.85024.cb

FIGURE 1. Representative gross appearances. A, Sectioned surface showing frequent different appearance between peripheral and central areas of the tumor. The former was largely beefy red, whereas the central area was white and softer. B, Tumor with bosselated external surface and white firm sectioned surface. C, Bilateral solid neoplasms that were rubbery. D, Multiple nodules are evident on the sectioned surface. Some residual ovarian parenchyma including a corpus luteum are also seen.

26 5/25/2013

Metastatic gastric carcinoma Metastatic gastric carcinoma: CK7

Uterine cervix Uterine cervix

• HPV associated and non HPV (minimal deviation • Frequently mimic primary ovarian mucinous neoplasm on adenocarcinoma) associated gross and microscopic evaluation • Metastases to ovary uncommon - Gross: Large, unilateral, multicystic, smooth capsule • Usually associated with previously or concurrently diagnosed (frequently violate algorithm) cervical carcinomas but sometimes cervical tumor diagnosed - Microscopic: Borderline tumor like growth pattern, subsequently expansile/cribriform growth pattern • Typically deeply invasive cervical primary • Also reported in cases with microinvasion and cases of AIS alone without unequivocal stromal invasion Only 3/29 cases bilateral with infiltrative growth pattern

Ronnett et al, Am J Surg Pathol 2008 Ronnett et al, Am J Surg Pathol 2008;32:1835-1853 Chang et al Int J Gynecol Pathol 2009

27 5/25/2013

Uterine cervix: distinction from ovarian primary Immunohistochemistry

• Gross and/or microscopic features of metastatic tumor • CK7>>CK20 • HPV-ISH (limited sensitivity) HPV associated cervical tumors: - Appropriate clinical history • p16 • Cytologic features: nuclear characteristics, apical mitoses and apoptotic bodies - HPV associated endocervical adenocarcinomas: Strong diffuse staining (90-100%) • Ancillary studies: p16, HPV DNA in situ hybridization - Non HPV associated endocervical carcinomas: Negative or focal staining Non-HPV associated tumors: - Primary ovarian tumors and metastases from noncervical primary sites: - Clinical history Predominantly p16 negative or focal - Morphologic similarity with cervical primary

Vang et al, Am J Surg Pathol 2007

Metastatic endocervical adenocarcinoma Metastatic endocervical adenocarcinoma

28 5/25/2013

Metastatic endocervical adenocarcinoma Metastatic endocervical adenocarcinoma:p16

CK7 CK20 Determining site of origin for mucinous tumors: Immunophenotype

Ovary Appendix/colorectal Pancreatobiliary tract Uterine cervix CK7 ++ -/+ ++ ++ CK20 +/- ++ -/+ -/+ CDX2 +/- ++ +/- +/- SMAD4 + + Loss in ~50% + p16 - - - ++

29 5/25/2013

Determining site of origin for mucinous Primary versus metastasis tumors: Immunophenotype Equivocal cases (overlapping features) Metastatic lower Metastatic upper Primary ovarian a gastrointestinal tract gastrointestinal tract - Diagnose as “Mucinous carcinoma involving Tumor type mucinous tumors b c adenocarcinomas adenocarcinomas (n= 42) (n= 29) (n= 19) ovary” and discuss the differential of primary CK7+/CDX2 - 25 (60%) 0 (-) 5 (26%) d versus metastasis CK7+/CDX2+ 15 (36%) 2 (7%) 12 (63%) e f CK7 -/CDX2+ 2 (5%) 24 (83%) 2 (11%) - “May be accepted as an ovarian primary if the CK7 -/CDX2- 0 (-) 3 (10%) 0 ( -) CK7+/CK20 - 7 (17%) 0 (-) 2 (11%) d possibility of extra-ovarian origin is clinically CK7+/CK20+ 33 (79%) 2 (7%) 15 (79%) e f CK7 -/CK20+ 2 (5%) 25 (86%) 2 (11%) and radiologically excluded” CK7 -/CK20- 0 (-) 2 (7%) 0 ( -)

Vang, et al. Mod Pathol 2006

Intraoperative assessment of ovarian mucinous lesions • Radiologic Intraoperative assessment of • Clinical ovarian mucinous lesions • Gross • Microscopic

Communication between surgeon and pathologist is key

30 5/25/2013

Intraoperative assessment of ovarian mucinous Intraoperative assessment of ovarian mucinous lesions lesions Clinical history - Prior history of mucinous neoplasm: Consider metastasis Radiology Gross features: - Bilateral ovarian involvement - Evidence of extra-ovarian disease Consider metastasis -Bilateral tumors of any size, unilateral <13 cm: - Lesion in another organ Metastatic Operative findings - Status of contralateral ovary -Unilateral > 13 cm: Primary - Ovarian surface status - Mucin or tumor in peritoneal cavity - Appearance of appendix Gross/microscopic features

Intraoperative assessment of ovarian mucinous Intraoperative assessment of ovarian mucinous lesions lesions • Microscopic features - consider metastasis: Implications of FS diagnosis: - Nodular growth - Mucinous cystadenoma: No staging - Desmoplasia - Mucinous cystadenoma with focal borderline - Infitrative growth features: May or may not stage - Signet ring cells - Mucinous borderline tumor: Staging (extent may - Mucin dissection depend on patient age) - Surface involvement - Mucinous carcinoma: Staging

If features suggestive of metastasis: Ask surgeon to - Metastatic tumors: No staging examine for another primary site particularly in the gastrointestinal tract (appendix)

31 5/25/2013

Intraoperative assessment of ovarian mucinous Mural nodules in ovarian mucinous neoplasms lesions

Ovarian mucinous lesion - Rare - Can occur in cystic mucinous tumors (cystadenomas, borderline tumors and carcinomas) - Single or multiple, variable size Large, unilateral Small, bilateral - Heterogeneous entities Low grade High grade Favor primary Benign: Sarcoma like mural nodules (SLMNs) Malignant: Favor metastasis Borderline/ Cystadenoma 1. Sarcomas carcinoma 2. Anaplastic carcinomas 3. Carcinosarcomas

Staging No staging

Mural nodules in mucinous cystic neoplasms Anaplastic carcinoma in ovarian mucinous neoplasms

Sarcoma like mural Anaplastic carcinoma • nodules Prognosis dependent on stage Number of nodules 1 to many Usually 1 • No correlation with histology, size, type of mucinous tumor, Size Small Large presence of lymphovascular invasion Circumscription Good Poor • May not be associated with adverse prognosis when stage Ia Necrosis Uncommon Common, extensive • May recur as high grade carcinoma/sarcoma Cell composition Heterogeneous Homogeneous Inflammation Marked Rare Epulis type giant cells Common, abundant Uncommon, focal Spindle cells Common Occasional (spindle cell carcinoma) Cytokeratin staining Negative/weak Positive

Provenza et al, Am J Surg Pathol 2008 Provenza et al, Am J Surg Pathol 2008

32 5/25/2013

Mucinous cystadenoma with sarcoma-like mural nodule Mucinous cystadenoma with sarcoma-like mural nodule

Mucinous cystadenoma with sarcoma-like mural nodule Mucinous cystadenoma with sarcoma-like mural nodule – CD68

33 5/25/2013

Mucinous cystadenoma with sarcomatoid carcinoma Mucinous cystadenoma with sarcomatoid carcinoma

Mucinous cystadenoma with sarcomatoid carcinoma - pankeratin Summary

• Focal epithelial proliferation can be seen in mucinous cystadenoma • Mucinous borderline tumors are benign and stage 1A (exclude metastasis if considering a diagnosis of advanced stage mucinous borderline tumor!)

34 5/25/2013

Summary Summary

• Primary ovarian mucinous carcinomas are • Gross and microscopic evaluation very helpful uncommon to differentiate between primary and • Metastatic mucinous carcinomas to the ovary metastasis (but remember the pitfalls) are more common • Adequate sampling important • Metastatic mucinous tumors to the ovary can • Immunophenotype helpful in some settings simulate ovarian primaries • Distinction has therapeutic and prognostic significance

Summary Summary

• Pseudomyxoma peritonei is frequently of • Mural nodules can be associated with appendiceal origin and virtually never of mucinous cystic tumors ovarian origin (exception mucinous tumor • These can be sarcoma-like or malignant arising in teratoma) (sarcomatoid carcinoma, anaplastic carcinoma • Can be high grade or low grade (no consensus or carcinosarcoma) on terminology) • Examine entire appendix carefully in cases of pseudomyxoma

35 5/25/2013

Thank you!