Intraductal Papillary Mucinous Neoplasm With Extensive Mural Osseous Metaplasia and Calcification

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1 CASE REPORT Intrductl Ppillry Mucinous Neoplsm With Extensive Murl Osseous Metplsi nd Clcifiction Runjn Chetty 1, Sngeeth N Klimuthu 1, Korosh Khlili 2 Deprtments of Pthology 1 nd Joint Deprtment of Medicl Imging 2, University Helth Network/ University of Toronto, Toronto, Cnd ABSTRACT Context This cse highlights the unusul rdiologicl findings of n intrductl ppillry mucinous neoplsm presenting s rdiologiclly opcified lesion. This correlted histologiclly with extensive ossifiction nd clcifiction of the wll of the cyst. Additionlly, n ccompnying intrductl tuulr denom msquerded s murl nodule. Cse report A seventy-yer old mn presented with vgue epigstric pin nd CT-scn reveled cystic pncretic lesion with egg-shell opcifiction of the cyst wll. Pthologicl exmintion confirmed n intrductl ppillry mucinous neoplsm of gstric type, low-grde dysplsi nd n ccompnying intrductl tuulr denom in the distl pncres. There ws extensive osseous metplsi nd dystrophic clcifiction within the wll of the intrductl ppillry mucinous neoplsm which ccounted for the opcifiction noted rdiologiclly. Bsed on these rdiologic findings, the ptient underwent distl pncretectomy nd splenectomy. Conclusions extensive osseous metplsi is exceedingly rre in intrductl ppillry mucinous neoplsm, especilly sufficient to result in rdiologicl opcifiction of the cyst nd the presence of concomitnt intrductl tuulr denom in gstric type intrductl ppillry mucinous neoplsm cn msquerde rdiologiclly s murl nodule. INTRODUCTION Intrductl ppillry mucinous neoplsms (IPMN) re detected with incresing frequency s more ptients re sujected to ever improving imging modlities. IPMN typiclly re cystic lesions tht re connected to pncretic ductl system nd hve well-chrcterized histologicl fetures nd su-types. IPMNs re importnt to recognize oth rdiologiclly nd pthologiclly s they re precursor lesion to pncretic denocrcinom, usully the mucinous vrint lthough conventionl ductl cncer is lso encountered with IPMN. The rdiologic exmintion of these lesions, especilly in sequentil fshion, is n importnt fcet of the mngement of erly lesions. Progression is monitored nd increse in size, complexity of the cystic lesion, murl nodule formtion, murl thickening, min duct involvement nd extension into surrounding pncretic prenchym re ll pointers towrds more ggressive ehviour, ie., development of invsive crcinom. Received Decemer 12th, Accepted Jnury 26th, 2018 Keywords Adenocrcinom; Crcinom; Pncres Arevitions IPMN intrductl ppillry mucinous neoplsm; MRI mgnetic resonnce imging Correspondence Runjn Chetty Deprtment of Pthology Toronto Generl Hospitl University Helth Network/Lortory Medicine Progrm 200 Elizeth Street, 11th Floor, Eton Wing Toronto, Ontrio M5G 2C4 Cnd Tel Fx E-mil runjn.chetty@uhn.c The presence of rdiologiclly detected murl opcifiction in IPMN is thought to occur in pproximtely 10-25% of IPMN. This usully occurs in lrger lesions nd when comined with other rdiologicl fetures my well e tken s sign of mlignncy within n IPMN [1, 2, 3, 4, 5]. It is lso importnt to seprte pncretic prenchyml clcifiction wy from the IPMN which is form of dystrophic clcifiction relted to chronic pncretitis nd/or ft necrosis. Osseous metplsi within the wll of n IPMN is exceedingly rre nd hs not een well-documented in the English lnguge literture, to the est of our knowledge. Murl osseous metplsi in high-grde gstric type IPMN with n ssocited tuulr denocrcinom hs een descried in the Jpnese literture [6]. We present gstric-type IPMN which hs three notle fetures tht wrrnt documenttion. Firstly, the rdiologicl fetures of the IPMN were unusul nd were tht of egg-shell opcifiction in prts of the mss. Secondly, histopthologiclly there ws extensive complete osseous metplsi (with one nd mrrow ft with hemtopoietic elements) in the cyst wll immeditely sujcent to the lining epithelium, nd thirdly, the luminl enhncing nodule ws due to the presence of n intrductl tuulr denom ccompnying the IPMN. CASE REPORT A seventy-yer old mn presented with dominl discomfort nd pin over period of 18 months prior to seeking medicl ttention. This ws not ccompnied y ny other signs or symptoms such s weight loss, norexi 43

2 or jundice. The ptient ws lifelong non-smoker with no dmitted history of lcohol consumption, nd there were no other relevnt clinicl findings. His mylse level ws 348U; clcium, rndom lood glucose (5.3 mmol/l), crcino-emryonic ntigen (0.9 ng/ml), CA19-9 (10 U/ml) nd CA125 (3 U/ml) levels were ll norml. As prt of the clinicl work up, the ptient underwent CT scn (with nd without contrst medium) of the domen demonstrting loulted, exophytic cystic lesion in the til of the pncres. The lesion hd internl septtions nd one of the cystic components hd thin murl, so-clled eggshell clcifiction (Figure 1-c). Additionlly, there ws vsculrized, enhncing 2.3 cm nodule within the cyst which suggested the possiility of mlignnt trnsformtion (Figure 1d-e). A MRI ws lso performed which ws of limited qulity. The MRI scn confirmed the cystic nture of the mss with thin internl septtions, nd norml pncretic duct without communiction with the mss. However, the enhncement of the solid ppillry nodule ws poorly pprecited on the MRI due to djcent rtifcts. Endoscopic ultrsound ws not performed pre-opertively. A distl pncretectomy nd splenectomy ws performed in view of the clinicl nd rdiologicl suspicion of mlignncy. The specimen consisted of portion of pncres mesuring cm contining cystic lesion mesuring cm (Figure 2). The lumen of the cyst contined ppillry, frile lesion mesuring 1.8 cm in mximl dimeter. Prts of the lesion hd detched nd were noted within the luminl deris. The cyst wll ws noted to e thick, ple nd mesured 0.1 cm in thickness. The cyst nd intrluminl lesion were smpled in totl. The ttched spleen ws unremrkle. c d e Figure 1. (). Axil unenhnced CT scn shows the fluid density cystic lesion in the pncretic til with n re of egg-shell clcifiction (rrow). There is seprte focus of clcifiction (rrowhed) which corresponded to the dystrophic clcifiction within the tuule-ppillry denom. (). Axil contrst enhnced imge t the sme level depicts the enhncing denom (rrow). (c). Sgittl unenhnced imge provides etter detil of the eggshell clcifiction (rrow) within the lesion rising exophyticlly off the til of the pncres (P). (d). Coronl enhnced CT scn shows optimlly the enhncing denom (rrow) nd norml pncretic duct (rrowhed). (e). Coronl T2 Weighted MRI demonstrtes the cystic nture of the mss with solid components (rrow) nd norml pncretic duct downstrem (rrowhed). 44

3 Histologicl evlution of the cyst showed it to e septte nd lined y gstric foveolr nd pyloric type mucos (Figure 3). The epithelium ws flt with smll ppillry infoldings nd tufts into the lumen. There ws mild pleomorphism, strtifiction nd hyperchromsi of nuclei, very rre mitoses nd undnt picl cytoplsmic mucin (Figure 3). The cytologic findings mounted to low-grde dysplsi. No evidence of highgrde dysplsi or invsive cncer ws seen nd the entire specimen ws exmined microscopiclly. In focl res the mucos ws either stripped or ttenuted. The intrluminl mss seen oth rdiologiclly nd on gross exmintion of the specimen ws tuulo-ppillry lesion lined y similr gstric-type epithelium s the min cystic structure nd ttched to the cyst wll. The epithelium ws MUC5AC positive ut MUC1 nd 2 negtive. A striking histologicl feture ws the widespred presence of osseous metplsi nd clcifiction within the wll of the min cyst nd in septum (Figure 4). The metplstic one ws locted in the firous tissue prt of the cyst wll, immeditely sujcent to the lining epithelium (Figure 4). Foclly, the one protruded into the lumen of the cyst cusing slight ttenution of the overlying epithelium (Figure 4). In prts, the osseous metplsi ws ccompnied y dystrophic clcifiction nd mrked hyliniztion of the wll. There ws no ossifiction or clcifiction noted within Figure 2. The distl pncretectomy specimen displying the cystic structure tht communicted with the min pncretic duct, n intrluminl component (rrow) nd the very distinct thick cyst wll. Figure 3. (). A low power imge of the cyst showing the intrluminl tuulo-ppillry denom nd septum. The cyst lining ws gstric pyloric nd foveolr in type with sl nuclei nd undnt cytoplsmic mucin. (). The epithelil dysplsi in this lesion ws low-grde. 45

4 Figure 4. (). The cyst wll nd microscopiclly noted septum showed mnly osseous metplsi nd some clcifiction. (). The osseous metplsi ws immeditely eneth the lining epithelium nd foclly protruded into the cyst lumen. the luminl contents of the cyst or infrcted/ulcerted prts of the intrductl tuulo-ppillry denom. The osseous metplsi nd ccompnying dystrophic clcifiction were regrded s secondry fetures nd result of longstnding, low-grde chronic inflmmtion. DISCUSSION As mentioned erlier, prominent osseous metplsi is distinctly rre occurrence in IPMN with single report occurring in the Jpnese literture [6]. In the cse presented herein, the one formtion ws detected rdiologiclly nd ws in excess of the ccompnying clcifiction. While osseous metplsi hs not een documented in IPMN, the presence of clcifiction hs nd its significnce evluted in severl pulictions [1, 2, 3, 4, 5]. Clcifiction hs een noted to occur in 2 loctions in IPMN, the wll of the cyst, nd within the lumen. Clcifiction within pncretic prenchym in the vicinity of the cyst is not relted to the IPMN per se nd is relted to chronic pncretitis resulting from ostruction within the pncretic duct system. The most frequent loction for clcifiction in IPMN is within the lumen nd relted to the mucus [1, 2, 3, 4]. In detiled study looking specificlly t clcifiction in IPMN, Perez-Johnston nd collegues exmined 164 IPMN nd found clcifiction in 33 cses (20%) [5]. They clssified the clcifiction s punctte, corse nd eggshell tht were distriuted in the wll most frequently (murl), septum, ducts, solid component nd comintions of the forementioned sites [5]. The cyst wll either lone or in comintion with other sites ws seen in 84% of the 33 cses with clcifiction [5]. Interestingly, there is no mention of ny cses contining ny osseous metplstic foci, ttesting to the rrity of its occurrence nd s dominnt histologic feture. Clcifiction tends to occur more frequently in lrger cysts especilly with ccompnying dilttion of the min pncretic duct [5]. Of itself, the presence of clcifiction did not portend the presence of invsive crcinom. Intrductl tuulr or tuulo-ppillry denoms re frequent feture of gstric-type IPMN nd occur in pproximtely 50% of these IPMN [7, 8]. Its occurrence in IPMN is thought to e loclized prolifertion of the neoplstic epithelium lining the cyst resulting in n intrluminl polypoid lesion. The lining epithelium of intrductl tuulo-ppillry denoms is morphologiclly nd moleculrly identicl to tht of gstric-type IPMN, nd these tuulo-ppillry lesions should not e regrded s seprte or distinct from IPMN-gstric (pyloric glnd) type [9]. From clinicl point of view, extensive rdiologicl opcifiction in n IPMN should not utomticlly invoke the possiility of invsive mlignncy. CONCLUSION This cse thus highlights three distinct fetures tht cn ccompny IPMN. The rdiologicl ppernce of eggshell clcifiction is n uncommon ut recognized feture of IPMN, histologiclly this ws due minly to complete osseous metplsi (one nd mrrow elements), nd finlly tht intrductl tuulr/tuulo-ppillry denoms lined y identicl epithelium s the gstric-type IPMN, is cuse of n intrluminl mss nd frequent ccompniment of IPMN-gstric type. Confilct of Interest Authors re declred tht there is no conflict of interest. References 1. Lesnik RJ, Hohenwlter MD, Tylor AJ. Spectrum of cuses of pncretic clcifictions. Am J Roentgenol 2002; 178: [PMID: ] 2. Kwmoto S, Lwler LP, Horton KM, Eng J, Hrun HR, Fishmn EK. MDCT of intrductl ppillry mucinous neoplsm of the pncres: evlution of the fetures predictive of invsive crcinom. Am J Roentgenol 2006; 186: [PMID: ] 3. Proccci C, Grzini R, Bicego E, Bergmo-Andreis I, Minrdi P, Zmini G, et l. Intrductl mucin producing tumors of the pncres: imge findings. Rdiology 1996; 198: [PMID: ] 46

5 4. Touli B, Vilgrin V, Vullierme MP, Terris B, Denys A, Suvnet A, et l. Intrductl ppillry mucinous tumors of the pncres: helicl CT with histopthologic correltion. Rdiology 2000; 217: [PMID: ] 5. Perez-Johnston R, Nrin O, Mino-Kenudson M, Ingkkul T, Wrshw AL, Fernndez-del Cstillo C, et l. Frequency nd significnce of clcifiction in IPMN. Pncretology 2013; 13:43-7. [PMID: ] 6. Omur N, Ono F, Or M, Sto J, Sto M, Ymmur A, Hirg M, et l. Intrductl Ppillry Mucinous Crcinom of the Pncres with Osseous Metplsi. Jpn J Gstroenterol Surg 2015: Chetty R, Serr S. Intrductl tuulr denom (pyloric glnd-type) of the pncres: repprisl nd possile reltionship with gstric-type intrductl ppillry mucinous neoplsm. Histopthology 2009; 55: [PMID: ] 8. Chetty R, Serr S, Rogll P. Pncretic intrductl tuulr denom in coexistent intrductl ppillry mucinous neoplsm msquerding rdiologiclly s murl nodule. Am J Digest Dis 2016; 3: Ymguchi H, Kuoki Y, Htori T, Ymmoto M, Shimizu K, Shirtori K, Shit N, et l. The discrete nture nd distinguishing moleculr fetures of pncretic intrductl tuuloppillry neoplsms nd intrductlppillry mucinous neoplsms of the gstric type, pyloric glnd vrint. J Pthol 2013; 231: [PMID: ] 47