[1540] Invasive Carcinomas Arising from Pancreatic Mucinous Cystic Neoplasms (MCNS) with Ovarian Stroma: A Clinicopathologic Analysis of 25 Cases with Invasive Carcinoma Identified in 131 MCNS.

Kee-Taek Jang, Nevra Dursun, Olca Basturk, Edward Stelow, Sudeshna Bandyopadhyay, NVolkan Adsay. Samsung Medical Center, Seoul, Korea; Emory, GA; MSKCC, NY; U of VA; WSU, MI

Background: The data on the incidence and clinicopathologic characteristics of invasive carcinoma (IC) arising in MCNs is rather limited because they are either concealed in studies analyzing all MCNs, or in those that did not employ the current sampling protocols or criteria (requirement of ovarian type stroma-OTS), or some authors had lumped them together with CIS under “malignant MCNs”. Not surprisingly, reported incidence of invasive MCN ranges from 2.9-28.6%.
Design: All 131 MCNs in the authors' files, defined by the presence of OTS were analyzed. Average number of blocks of tumor examined was 18.
Results: 25/131 cases (19%) had IC; the remainders were 78 with low-grade dysplasia (LGD), 20 intermediate, and 8 high-grade dysplasia (HGD/CIS). The cases with IC had the following characteristics (as opposed to the non-invasive MCNs): All female, mean age=53 yrs (vs 49; p=0.228), mean tumor size=9.3 cm (range, 3.5-15 cm; vs 5.5cm; p=0.001), elevated serum CA19-9 detected in 7/10 (vs 8/47; p=0.001). Invasion was suspected preoperatively in 6 cases. MCN component of all 25 IC cases had in-situ papillary areas (9/25 in the form of >0.5 cm florid papillary nodules) and 13/25 had extensive HGD/CIS. In 4 cases, the MCN component was partially obliterated by the IC (IC was larger than MCN component). Mean size of IC was 1 cm; staged (per the recent proposal according to size of invasion) as T1a (<0.5 cm) in 11 cases (77%), T1b (0.5-1 cm) in 2 (12%) and T1c (1-2 cm) in 1 and T2 in 5. Invasion was confined to the mural nodule in 9 cases; showed pericapsular extension in 14, and adjacent organ involvement in 2. 19 ICs were ordinary ductal carcinoma, 1 was papillary (in-situ like), and 4 was undifferentiated (1 osteoclastic-giant cell type; 1 sarcomatous; 2 epithelioid). None was colloid type. Lymph node metastasis was seen in 2, liver metastasis in 3, and peritoneal spread in 3. The actuarial 5-yr survival of IC cases was 26%.
Conclusions: Invasive carcinomas occur in 19% of resected MCNs (with ovarian stroma). These arise in larger MCNs, often in the background of papillary nodules and extensive HGD/CIS. Most (75%) are of tubular (ductal) type, others are undifferentiated, but none are colloid (mucinous). Most are small (<0.5 cm), qualify as T1a; however, even the small ones can lead to fatalities (one death and one recurrence). Invasive carcinomas arising in MCNs are agressive tumors, with 5-yr survival of 26%.
Category: Liver & Pancreas

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 197, Tuesday Afternoon


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