Gastrointestinal Case Clinical 30 year old female Acute onset - PowerPoint PPT Presentation

Gastrointestinal Case

Clinical • 30 year old female • Acute onset right lower quadrant pain – emergency room • CT scan - probable appendicitis • OR - appendectomy • Operative findings: • 2 cm appendiceal mass with tumor adherent to the terminal ileum and its mesentery

Pathology • “Appendix” • 2.9 x 2.2 x 1.8 cm tan-pink to red soft tissue with a 1.9 cm linear staple line • External surface: granular with focal areas of fibrous adhesions • Gross evaluation: • Lumen ranging from 0.2 cm to 0.7 cm • Wall thickness 0.2 to 0.9 cm with a dense white fibrous cut surface • But ….“No lesions were identified” • Entirely submitted

What is your diagnosis? A. Low-grade appendiceal mucinous neoplasm (LAMN) B. LAMN with endometriosis C. Invasive mucinous adenocarcinoma D. Endometriosis

PAX-8 CDX2

CDX2 ER

ER

ER

Diagnosis • MDACC: Endometriosis with intestinal metaplasia (referring diagnosis: LAMN and endometriosis)

Discussion • Endometriosis not an uncommon finding in the gastrointestinal tract • Form polypoid or mass lesions or cause perforation occasionally with hemoperitoneum • Mimic metastatic adenocarcinoma in abdominal lesions in patients with known malignancy undergoing diagnostic procedures • Appendix – associated with acute appendicitis, perforation, mucoceles Uwaezuoke Ethiop J Health Sci 23 3013 Clement Adv Anat Pathol 14 2007 Hapke Human Pathol 8 1977 Curbelo-Peña J Surg Case Reports 8 2015

Unusual Forms of Endometriosis • Stroma only • Decidualized forms • Metaplastic • Colonization of normal mucosa • Dysplasia/neoplasia arising in endometriosis

• 6 patients , 39-71 years • All with masses (3 appendiceal, 2 cecal, 1 ”pelvic” (adnexal mass adherent to appendix with mucin pools) • 3 appendectomy +/- cecectomy; 2 right hemicolectomy, 1 appendectomy with hysterectomy and bilateral salpingo-ophorectomy • 5 referring diagnosis was mucinous appendiceal neoplasm (mucinous cystadenoma, LAMN, or mucinous adenocarcinoma) • All had mucin pools in the mesoappendix or serosa • Appendix completely submitted in all • Follow-up 1-7 years (mean 3.6); no PMP Misdraji Am J Surg Pathol 38 2014

Endometriosis Mimicking LAMN All patients: endometriosis with endometrial- type, “goblet - like”, and intestinal-type glands with some transitions Misdraji Am J Surg Pathol 38 2014

“Metaplasia” in Endometriosis • Ciliated • Eosinophilic • Hobnail • Squamous • Mucinous • Endocervical type (usual) • Intestinal type – “goblet - like” mucinous cells, goblet cells, Paneth cells (rare) • Metaplasia • Colonization Clement Adv Anat Pathol 14 2007 Kim Pathol 45 2013 Vyas Pathol Res Pract 213 2017

LAMN COLONIZED BY ENDOMETRIOSIS Mai Histopathol 35 1999 Mitchell Diagn Pathol 9 2014 Libbrecht Virchows Arch 461 2012

Conclusions • Most mucinous lesions of the appendix need extensive/complete sampling – distinguish benign lesions and neoplasms • Endometriosis is not uncommon in the gastrointestinal tract, can occasionally have intestinal differentiation, can colonize mucosa, and become neoplastic • Multiple lesions (benign and neoplastic, multiple neoplastic) may co-exist in the appendix