Team III Conference

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Mucocele and Pseudomyxoma Peritonei

• Team III Conference
• Edward Chin, M.D.
• March 20, 2003

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Case

• 60M with hematuria on routine U/A
• Hx reveals abdominal pain x 3 months
• Benign abdominal exam
• CT scan

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Workup

• CT-guided aspiration of pelvic fluid
• Analysis mucinous adenocarcinoma
• Taken to OR on 3/6/03 for exploratory laparoscopy

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Operative Course

• Diffuse, mucinous material throughout
• Appendiceal mass
• Findings discussed with family
• ? laparotomy
• Appendix, omentum, peritoneum removed
• Larger nodules ablated with ABC
• Tenckhoff catheter placed

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Post-operative Course

• Intra-abdominal chemotherapy begun on POD1,
  continued x 5 days
• Prolonged hospital course 2nd chemo-induced
  diarrhea
• D/cd POD12
• Pathology well-differentiated invasive mucinous
  adenocarcinoma, mucin pools with calcifications

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Appendiceal Cancer

• 1 of appendectomies contain cancer
• 2/3 carcinoid (50 all GI carcinoids are
  appendiceal)
• Tan-yellow mass, surrounding desmoplastic
  reaction
• lt 2 cm ? no further treatment
• gt 2 cm ? R hemicolectomy
• Remainder mucinous cystadenocarcinoma,
  adenocarcinoma, adenocarcinoid
• Adenocarcinoma associated with metastatic disease
  50 of time (likely 2nd appendiceal rupture,
  tumor spread)

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Appendiceal mucocele

• Dilated, mucin-filled appendix
• 0.3 of all appendectomies
• 4 histologic categories
• 1) Retention cyst simple mucocele (normal
  mucosa)
• 2) Mucosal hyperplasia
• 3) Mucinous cystadenoma ( papillary adenoma
  of colon)
• 4) Mucinous cystadenocarcinoma
• Contemporary Surgery, 2002 58 (12), 609-613

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Mucoceles pathophysiology

• Obstruction of appendiceal lumen ? dilation with
  mucin
• Obstruction 2nd hyperplasia or fecalith
• Presentation depends on nature/degree of
  obstruction
• Slow, chronic ? large mucocele formation
• Fecalith ? acute inflammation, with mucinous
  content

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Mucoceles natural history

• Asymptomatic (25), vs. chronic RLQ pain vs.
  acute appendicitis
• Mucocele can also lead to
• Bowel obstruction 2nd intussusception ? cecum
• Torsion ? gangrenous appendix
• Rupture ? mucinous ascites, pseudomyxoma
  peritonei
• Risk factor for colon cancer (synchronous,
  metachronous)

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Differential Diagnosis

• Duplication cyst
• Mesenteric/omental cyst
• Ovarian cyst
• Periappendiceal abscess

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Mucoceles treatment

• Hyperplasia, mucinous cystadenoma treated by
  simple appendectomy
• Malignant mucocele
• Preop/intraop suspicion ? R hemicolectomy, or
  appendectomy and frozen section
• Post-op diagnosis ? return for definitive
  procedure

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Pseudomyxoma Peritonei

• Extremely rare 300 cases/yr in U.S.
• Diffuse, intraperitoneal collection of gelatinous
  fluid with mucinous tumor implants on peritoneal
  surfaces and omentum
• Strictly, etiology is 2nd grade I mucinous
  cystadenocarcinoma of the appendix
• Ovarian, pancreatic cancer ? similar picture

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Pathophysiology

• Mucocele rupture ? dissemination of
  mucin-producing tumor cells throughout peritoneal
  cavity
• Characteristic and predictable pattern of tumor
  progression
• Gravity ? dependent collection of tumor
• (pelvis, retrohepatic space, paracolic gutters,
  Treitz)
• 2) Resorption of peritoneal fluid ? accumulation
  of tumor cells to distinct sites
• Sugarbaker, PA. Histopathology 2001 39,
  525-528.

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Deposit Sites 2nd Fluid Resorption

• 1) Between liver, R hemidiaphragm
• -2nd lymphatics within undersurface of
  hemidiaphragm
• 2) Greater, lesser omentum
• -lymphatics draw fluid, attracting tumor cells
  to their surface ? omental caking
• Sugarbaker, PA. Histopathology 2001 39, 525-528

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Sugarbaker Protocol

• Radical debulking of tumor load
• appendix, peritoneum, omentum
• additional viscera as indicated
• Curative therapy all nodules gt 2.5 mm
• Intraoperative heated mitomycin
• Post-operative 5-FU
• Reports of 80 10 yr survival

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Rationale for Radical Surgery

• Low aggressiveness of tumor rare LN or liver
  involvement
• Peritoneal dissemination occurs early
• Areas of spread are treatable by
  peritonectomy/omentectomy
• Redistribution phenomenon small bowel is largely
  spared (2nd motility?)
• Regional chemotherapy can attack all surfaces
  exposed to tumor
• Sugarbaker, PA. EJSO 2001 27 239-243

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Results

• 385 patients undergoing surgery with intraop
  chemo
• Post-op tx based on histology
• Mucinous adenoca ? 5 days of 5-FU
• Adenomucinosis ? none
• Morbidity 27, mortality 2.7
• Pancreatitis, EC fistula
• Sugarbaker, PA. EJSO 2001 27 239-243

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Survival
Sugarbaker, PA. EJSO 2001 27 239-243
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Survival
Sugarbaker, PA. EJSO 2001 27 239-243
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Further

• Other reports have 5-year survival of 50-75
• CEA, CA 19-9 of some use in surveillance
• Laparoscopic treatment reported by select
  institutions (Cleveland Clinic)