Rare Mesenteric Location of MeckeVsDiverticulum, A Forgotten Entity: A Case Study

Aboard USS Kitty HawkSCOTT D. SEGAl, D.O.,* DAN S. ALBRECHT, D.O.,+ KRIS M. BELLAND, D.O., ERIC A. ELSTER, M.D/ , t§

From Ilk' *Mcdicnl Department, USS Kitty Hawk (CV'63), Yokosuka, japan; fLaboratory MedicineDepartment, Naval Medical Center, Portsmouth, Viv^iuia; tThe Department of General Sur^erxf, National

Naval Medical Center. Bi'thesda, Maryland; ^Radiation and Combat Injury Repair Department, CombatCa$ualti/ Care, Na-ral Medical Research Center, Silver Spring, Maryland

The traditional understanding of Meckel's diverticulum has always emphasized its antimesen-teric location, ever since its original description in 1809. We report the finding of an acutelyinflamed mass located on the mesenteric aspect of distal ileuni, which was discovered during aceliotomy performed aboard a U.S. Navy aircraft carrier. Pathological features of this unusualmass, including focal submucosal abscess formation, proximity to the ileocecal valve, and het-erotopic gastric tissue are all characteristic of inflammatory Meckel's diverticulum. The atypicalintraoperative finding of a desmoplastic reaction associated with this lesion is discussed withinthe context of a pertinent differential diagnosis. In addition, both the pathological characteristicsand the unusual location of this mass are the basis for a discussion that revisits a 50-year-oldsurgical controversy regarding Meckel's diverticulum.

M HCKEL'S DiVKRTiciJLUM w;is first described in1S()9 by Johann Friedrick Mcckcl as an ciiihryo-

logical rcmnanl caused by failure of the vUeliine ductto involute by the seventh or eighth week of gesta-tion.' - Approximately 90 percent of all vitelline ductunonialies ure Meckel's diveriicula. which are c(Misid-ered to be the most prevalent congenital anomalies ofthe gastrointestinal tract."* Infrequently, vitelline ductanomalies are associated with niesodiverticular bandsthought to be derived from persistent left vitelline ar-tery.*̂ As early as 1941. Chaffin described a case ofMeckeTs diverticulum attached close to the mesenter-ic bt>rder of the gut and postulated that this atypicallocation may have resulted from traction induced by apersistent vitelline artery."" Less than a decade later,however. Jay and co-workers developed conservativediagnostic criteria for MeckeTs dictating that the di-verticulum must arise from the antimesenteric borderof the gut proximal to the ileocecal valve, contain allfive layers of small intestine, and have a separate mes-

The views expressed in this article arc those of the auth<»rs andlid not reflect ihc olTicial pniiey of the Depanment of the Navy, theDepartment of Defense. i>r the U.S. Guvernment.

AJiiress edrrespiniUeiKL' iind reprint requests in Eric A. Bister.M.n . Radiation and COinbat Injury Repair Dep:innient. ComhatCasualty Care. Naxal MeJicai Research Center. 503 Robert GrantAvc. Silver Spring. MD 20910-7500.

entery for blood supply.-'' The following case presen-tation challenges these strict criteria, wbich haveser\ed as a mainstay of modern surgical practice tortnore than half a century.

Case ReportA l*J-ycar old white male presetited while onboard USS

Kiiiy Hawk with a 24-hour history of diffuse abdominal painthiit subseL|uentK localized tt> the right lower quadrant. Thispain was associated with two episodes of nausea and vtim-iting. Prior tn presentation, the patient wys without an-orexia, diarrhea. hetiiatOLhe/ia. or melena. He denied hav-ing any urinary symptoms of dysuria. heniaturia. urgency,or freqttcncy. His past medical history was significant onlyfor long standing nodular acne treated chronically with 100inu oral doxycycline twice daily. The remainder of the pa-tient's niedical and surgical history was noncontributory.

On physical exam, the patient was afebrile. normoteti-sive. and had a normal pulse and respiraioiv rate. His ah-dominal exam was remarkable for right h>wer qtiadrant ten-derness, Rovsing's sign, and general rebound tenderness.Laboratory studies incltided a white blood cell count of 14.6X IOV .̂L with a signiticaiit left shift secondary to markedbandetnia. L'rinalysis, electrolytes, liver function tests, andamylasc wetv all within normal limits. LMuasoinid of theabdomen revealed no free peritoneal Ouid or abdominalabscess. The appendix was not visualized on ultrasoLind.With a presumptive diagnosis of acute appendicitis, the pa-tient was taken to USS Kilty Hank's shipboard operatingroom for exploration.

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986 THE AMERICAN SURGEON Novetnber 2004 Vol. 70

After the induction of general anesthesia, a standard ex-ploration was performed through a low transverse rightlower quadrant abdominal incision. An abnormal mass waspalpated in the midileuni during the routine abdominal ex-ploration. This inflammatory mass was 3.5 em x 2.5 cm.originating from the mesenteric border of ileum approxi-mately 63.5 cm (25 in.) proximal to the ileocecal valve. Theadjacent mesentery was foreshortened with mesentericthickening and adenopathy 7.5 cm proximal and 5 cm distalto the mass. After a small bowel resection with wide localexcision of the mesentery was performed, the small bowelwas examined from the ligatnent of Trietz to the iieocecalvalve to ensure no additional lesions were present. Palpationof the colon and liver revealed no obvious masses. An ap-pendectomy was performed, and the incision was closed ina routine fashion. This patient's subsequent postoperativecourse was unremarkable.

Pathological Findings

Gross examination revealed a portion of previouslyopened small bowel with two stapled ends and a nod-ule that was located at the midportion. This nodulemeasured 3.5 x 4.0 cm and protruded from the serosalsurface of the small bowel 2 cm in width. The mucosallining appeared grossly unremarkable and had a paletan variegated surface. There was one area of the mu-cosal surface adjacent to the subserosal surface of themass that appeared edematous. Blunt probing of theentire mueosal surface adjacent to the mass revealedno obvious communication of the mass with the mu-cosal surface in the form of a diverticulum.

Serial sectioning of the resected nodule revealed awhorled gray-tan mass with some cystic spaces thatappeared to surface beneath the submucosa but did notappear to communicate with the mueosal surface. Theremaining nodule was notable for an area of lightbrown to tan whorled tissue that revealed cystic yel-low-green material. There was also a second smallnodule that was attached to the predotninant noduletissue that was cystic in character (Fig. 1). Focal sub-mucosal abscess formation within the wails of the nod-ule was present. Both acute and chronic transmuralinflammatory infiltrate was noted along with serositis.

Microscopic imaging of this lesion yielded addi-tional evidence of the inflammatory nature of the re-sected mass. There were areas of diffuse subserosalacute and cbronic inflammatory infiltrate on micros-copy (Fig. 2). Gastric metaplasia was found within theresected tnass adjacent to identifiable stnall bowel tnu-cosa (Fig. 3). Gastric mucosa, glands, and pits adjacentto small bowel mucosa were associated with submu-cosal edema and scattered inflammatory cell infiltrate(Fig. 4). Of note, during pathological review of thismass, on microscopy no communication between theinner lumen of the mass and the adjacent small bowelcould be demonstrated.

FiG. 1. Gross view of resected small bowel mass demonstrat-ing focal subniLieosal abscess formation.

FIG. 2. Area of diffuse subserosal acute and chronic intlam-matory infiltrate (Olympus Provis. AX 80. magnification x40).

The resected vermiform appendix measured 4.5 x0.8 X 2.4 cm and appeared grossly unretnarkable. Onsectioning, there was itnpacted fecal tnatetial withinthe ptoxitnal aspect of the appendix. The appendicealwall was focally attenuated, and the bivalved portionof the tip appeared tan-gray without evidence of exu-date or obstruction.

Discussion

The foremost concern of this case was the appro-priate intraoperative management of such an unusualtnass. Consideration of neoplastic processes in the in-traoperative differential diagnosis of this tnass wasparamount to any surgical intervention. The mesenter-ic destnoplastic reaction that was noted prior to resec-tion of the tnass suggested a carcinoid tumor. Thedifferential also included gastrointestinal stromal tu-mor (GIST), lytnphoma, adenocarcinoma. amelano-cytic melanoma, and metastatic process. Without pre-operative lymphadenopathy or LDH elevation, the

No. 11 RARE MESENTERIC LOCATION OF MECKEL'S DIVERTICULUM Segal et al. 987

Fiti. 3. Aiea ol yastric ineiaplasia within a portion of tbe re-sected mass (Olympus Provis. AX 80, magnification x4()).

i [(.. 4. Gastric mucosa. ghiiids. and pits adjacent to smallhowcl mucosa uith associated snbniucosal edema and scatteredinllamniatory cell infiltrate (Olympus Provis. AX 80, magnifica-tion x20).

diagnosis of tnalignant lytnphoma was less likely butnot itnprobable. For the above-mentioned potential di-agnoses, wide local excision was the treatment ofchoice for both diagnostic and therapeutic purposes.Other small bowel tumors such as lipoma. hamattoma.and neurogenic tumors were also included in the dif-ferential diagnosis.

Infectious etiologies such as hypertrophic intestinaltuberculosis were considered but deemed highly un-likely given a normal preoperative pulmonary examand review of systems. Mesenteric abscess fromCrohn's disease was also considered unlikely becausethe patient did not exhibit typical signs and sytnptomsof inflammatory bowel disease. Foreign body perfora-tion was another consideration, but other diagnosessuch as small bowel diverticulum. cystic small bowelduplication, and Meckel's diverticulum were decid-edly tnore probable. The mesenterie location of the

mass was most suggestive of a small bowel diverticu-lum or enterogenous cyst, but an extensive review ofthe literature failed to identify a case report of diver-ticulum or duplication presenting as an inflatnmatorymass. Congenital diverticula atid enterogenous cystsof the small bowel are both extremely rare, and ifsymptomatic will typically cause only gastrointestinalhemorrhage or obstruction.'^ MeckeFs diverticulumwas an imtnediate consideration as this diagnosis wasconsistent with the clinical picture and location of themass with respect to the ileocecal valve; however, thelikelihood of that diagnosis was initially questionedwhen the tnass was noted to be on the mesentericborder.

Our case is an obvious example of a small bowelmass that required resection because of its clinicalpresentation and gross /// vivo morphology. The exactdiagnosis of this mass, on the other hand, is ratherambiguous. The clinical presentation, location fromthe ileocecal valve, and inflammatory nature of thisma.ss was clearly more typical of Meckel's. The ab-sence of a distinct comtnunication of the mass with theadjacent intestinal lumen, however, suggests an enter-ogenous cyst or duplication. Theoretically, this massmust have communicated with the lutnen of adjacentbowel for it to become a source of inflammation andinfection, which may have subsequently obliterated asa result of the inflammatory process. The extent ofabscess formation without rupture may have been per-mitted by the chionic exposure of this patient to doxy-cycline, a tetracycline that achieves high concentra-tions in the intestine by virtue of its incompleteintestinal absorption.* "̂ Unfortunately, the presence ofheterotopic gastric mucosa within the lesion does notdistinguish between enterogenous cysts and Meckel'sdiverticula because both of these diagnoses have beenshown to contain this tissue. We favor the diagnosis ofMeckel's diverticuium based on the clinical presenta-tion of our patient but cannot rule out the possibilitythat this was an example of an atypical enterogenouscyst.

Should this mass have been found incidentally in anoninflammatory state, the intraoperative decision toresect the tnass would not have been straightforward.The inttaoperative diagnosis of an iticidental mass lo-cated adjacent to the mesentery would most likelyhave been a small bowel diverticulum or enterogenouscyst. Incidental jejunoileal enterogenous cysts and di-verticula are typically not treated surgically unlesssymptoms or complications are present.^ If our pa-tient's mass was an incidental finding in the yearsprior to its inflammatory state, it may have been mis-taken for a small bowel diverticulum or enterogenouscyst and may never have been resected. Some evi-dence has suggested that incidentally found Meckel's

988 THE AMERICAN SURGEON November 2004 Vol. 70

diverticula should be resected to prevent the long-terminflammatory, hetnorrhagic, obstructive, and neoplas-tic complications of this condition. In a recent epide-miological survey. Cullen et al. demonstrated that thebenefits of incidental Meckel's diverticulectomy out-weigh the surgical risk of an elective procedure in theirstudy population.*^

This unusual case is a reminder that Meckel's di-verticulutn may in fact occur on the tnesenteric borderof the small bowel. After an exhaustive search throughthe literature, the only other reported case of a mes-enteric-sided Meckel's diverticulum we found was thealoretnentioned Chaffin article of 1941.-'' The findingsof these two rare cases suggest that revision may needto be made to the classification of Meckel's diverticu-lum that has been followed since the 1950s. Further-more, modification of the current surgical manage-ment of incidental masses found on the tnesentericside of ileum must be considered. Prophylactic resec-tion of asymptomatic incidental tnesenteric-sidedmasses may be indicated to prevent cotnplicationsfrom a missed Meckel's diverticulum in this atypicallocation.

REFERENCES

1. Edmundson JM. Johann Friedrieh Meckel the younger:Meckel's diverticnium. Gastrointest Endosc 2001 ;54:I9A-2OA.

2. YahchoLichy EK. Marano AF. Etienne JF. Fingerhut AL.MeckePs diverticulum. J Am Coll Surg 2001; 192:658-62.

3. Turgeon DK, Barnett JL. MeckeKs diverticulum. Am J Gas-troenterol 1990:85:777-81.

4. Rutherford RB. Akers DR. Meckel's diverticulum: a reviewof 148 pediatric patients, with special reference to the pattern ofbleeding and to mesodiverticular vascular bands. Surgery 1966;59:618-26.

5. Holiinshead WH. The jejunum, ileum, and eolon. In Hollin-shead WH. ed. Anatomy for Surgeons: Volume 2. New York:Harper and Row, 1971.

6. Sande MA. Mandcll GL, Antimicrobial agents |continiiedltetracyclines. chloramphcnicol. erythromycin, and miscellaneousantihacterial agents. In Goodman LS. Gilnian A. eds. The Phar-macological Basis of Therapeutics. New York: McGraw-Hill,1993.

7. Uthoff SMS. Galadiuk S. Diverticular disease of the smallbowel. In Cameron JL. ed. Current Surgical Therapy. St. Louis:Mosby. 2001.

8. Cullen JJ, Kelly KA. Moir CR. et. al. Surgical managementof Meckel's diverticulum. An epidemiologic. population-basedstudy. Ann Surg 1994:220:564-9.