P s e u d o l i p o m a t o s e m u q u e u s e r e c t o s i g m o ' i d i e n n e r(~v(~l(~e p a r u n e diarrh(~e c h r o n i q u e

D i s c u s s i o n p h y s i o p a t h o l o g i q u e ~ p r o p o s d 'un cas e t r e v u e de la l i t t (~rature

J.-M. P R I G N E T *, E. C A R L O Z **, D. K U N K E L *

�9 Service de Pa tho log ie Diges t ive ( D o c t e u r D. Ki~nkel)

�9 * Service d ' A n a t o m o p a t h o l o g i e (Pro fes seur C. Pierre)

HOpi ta l d ' l n s t ruc t ion des A r m d e s Sa in te -Anne , T o u l o n N a v a l

Mucosal pseudolipomatosis of the rectosigmoid revealed by a chronic diarrhoea Pathogenesis discussion about one case and review of the literature

RESUMt~

Les auteurs rapportent un cas de pseudolipomatose muqueuse rectosigmo]dienne ddcouvcrt lors de l'inventaire etiologique d'une diarrhee chronique chez un homme de 31 ans. Apropos de cette observation et dcs donndes de la lindrature, ils discutent les mecanismes physiopathologiques et le rele deldtbre possible de la coloscopie.

SUMMARY

The authors report a case of mucosal pseudolipornatosis of the rectosigmoid revealed during investigations of a chronic diarrhoea in a 31 years" old man. About this" case and upon literature, they dis'cuss the pathogenic mechanisms and the possible implication of the colonoscopy.

I N T R O D U C T I O N

La pseudol ipomatose muqueuse colique est recon- nue comme une complication rare de la coloscopie. Elle est souvent asymptomatique. Si l 'aspect histolo- gique est stereotype, les constatations endoscopiques sont variables et le mecanisme incertain. Nous rap- portons une observation de pseudol ipomatose recto- s igmofdienne revelde par une diarrh~e chron ique pour laquelte le r61e declenchant de la coloscopie est douteux.

O B S E R V A T I O N

Un homme de 31 ans sans antecedent ni habitude toxique ddcrivait depuis deux mois une diarrhee glai- reuse diurne et des douleurs coliques. L'~tat general 6tait conserve. L ' examen clinique, l ' inventaire biolo-

gique de cette diarrhee, l ' echographie abdomina le furent normaux. L'ildocoloscopie (prdparde par Poly- ethylene-glycol) ne rdvelait qu 'un adenome tubul6 rectal rdsequ6 h l 'anse d ia thermique . Le rec tum n 'e ta i t pas biopsi6. La pers is tance de la d ia r rhee conduisait deux mois plus tard h rdaliser une endo- scopie courte prdparde par Normacol | lavement. Si l 'aspect macroscopique demeurai t normal, les biop- sies dtagees du rectosigmo~de rdvelaient la presence de vacuoles in t ramuqueuses , op t i quemen t vides (Figure 1) mimant des adipocytes. L'dpithdlium et les cryptes 6taient normaux. I1 n 'exis ta i t ni a l tera t ion vasculaire ni pneuma tose sous-muqueuse associde. En l 'absence de traitement, la diarrhee disparaissait en trois semaines. Des biopsies de contrele, huit mois plus tard, revdlaient l ' absence de recidive, Le dia- gnostic re tenu fut celui de pseudol ipomatose recto- sigmo)'dienne. Le r61e de la coloscopie effectude deux mois avant le diagnostic, n ' ayan t pas aggrav6 les symptemes, est discutable.

Tires ,~ part : D r J.-M. PRIGNET, H6pital d'Instruction des Armees Sainte-Anne - BP 600 - 83800 Toulon Naval.

Mots-cl&: colon maladies, coloscopie, effets adverses. Key-words: adverse effects, colonic diseases, colonoscopy.

Acta Endoscopica Volume 25 - N ~ 2 - 1995 175

Figure l a

Biopsie rectale - Colorat ion HES - x 100. Pseudol ipornatose rectale.

Rectal b iopsy - HES Colorat ion - x 100.

Rectal pseudol ipomatos is .

Figure 1 b x 200.

D I S C U S S I O N

La pseudolipomatose muqueuse du colon a 6t6 ainsi nomm6e pour la premiere fois en 1985 par Snover e t al. ~ p r o p o s de 24 observations [7]. Des auteurs avaient auparavant rapport6 des cas de ~ lipo- matose >> de la muqueuse rectocolique. Les colora- tions sp6cifiques des graisses (Red Oil O, noir Sou- dan B), des mucines (PAS), les 6tudes en lumi6re polaris6e [10] et ultrastructurales [7, 10] ont prouv6 l'absence d'adipocyte.

L'aspect microscopique est caract6ristique de cette affection: pr6sence de vacuoles intra-muqueuses optiquement vides de 20 ~t 130 pm. Ces aires kys- tiques refoulent les cellules adjacentes de la lamina propria dont le noyau, tangeant ~ la vacuole peut mimer l'aspect d'un adipocyte. S'il existe parfois une discrete collag6nisation p6rikystique, l'6pith61ium de surface, les cryptes et les glandes, les vaisseaux sont indemnes. La sous-muqueuse est intacte.

L'aspect macroscopique n'est pas univoque. La muqueuse de notre patient 6tait normale. Ben Rejeb a d6crit une st6nose axiale rdguli6re et molle du sig- mo'fde 6voquant un lymphangiome ou une tumeur graisseuse [1]. Cependant les aspects classiques sont des plaques superficielles ou ~a peine sur61ev6es, uniques ou multiples, millim6triques ~ centim6- triques, blanches ou jaun~tres, mimant des pseudo- membranes [4, 7, 10], sur fond 6ryth6mateux discret ~i intense [8].

La physiopathologie de l'affection demeure controvers6e. Pour Jonas, la muqueuse 6tait macro- scopiquement normale clans vingt cas ~ l'introduction de I 'endoscope ; ies 16sions apparaissant en cours d'examen [4]. La proc6dure de d6sinfection de l'en- doscope a 6t6 incrimin6e (irrigation des canaux op6- rateurs au peroxyde d'hydrog~ne ~t 3% pendant 10 minutes). L'auteur constatait la disparition de tout cas (sauf une fois) apr6s l 'abandon de cette d6marche. Le pouvoir oxydant du peroxyde d'hydro- g6ne, responsable d'effervescence, pouvait expliquer l'aspect observ6. Les colites chimiques aprbs lave- merit ~ l'eau savonneuse ou additionn6e de peroxyde d'hydrog6ne reproduisent ce m6canisme, de m6me, l'irrigation exp6rimentale du colon murin, en moins d'une minute. Des modifications histologiques vacuolaires sont alors observ6es.

Cependant, les autres auteurs, dont Snover, n'ont jamais effectual une telle proc6dure de d6sinfection. Une contamination des canaux op6rateurs par le glu- taralddhyde a 6t6 envisag6e, d'autant que les cas de pseudolipomatose survenaient surtout en fin de s6ance d'endoscopie [4, 5]. I,a faible incidence de l'af- fection : 0,3 5 1,7 % des coloscopies [4, 7, 10] plaide contre cette hypoth6se de m6me que l'observation de Ben Rejeb d'un patient n'ayant subi ant6rieurement qu'une rectoscopie [1].

Pour Waring qui en rapporte quatre cas, les 16sions 6taient prdsentes d6s la premiere endoscopie [10]. L'interpr6tation retenue est celle d'une issue trans- 6pithdliale de gaz intra-luminat par barotraumatisme iatrogbne. Sur muqueuse saine le gaz resterait intra- muqueux ; il diffuserait vers la sous-muqueuse dans le cas contraire [6, 8, 11]. L'association non rare: 5 cas sur 25 pour Gagliardi [3], 3 cas sur 10 pour Suarez [9] d'une pseudolipomatose et d'une pneumatose kys- tique peut t6moigner de ce m6canisme. Ce barotrau- matisme iatrog~ne serait lid a la technique d'explora- tion puisque comme le rappellent Shover et Cox, certain endoscopistes avertis n'en observent jamais [2], ce que rdfute Jonas [5]. Toutefois, les tentatives ?a reproduire sur le cadavre une pseudolipomatose par insufflation ou instillation pari6tale colique de gaz ont 6chou6 [7, 10] et ce m6canisme ne peut doric tout expliquer.

La symptomatologie, tr6s variable, ne permet de dater nile d6but de l'affection ni sa chronologie par rapport ~ une endoscopie. La plupart des observa- tions rapport6es sont d6couvertes fortuitement lors d'endoscopies de d6pistage [7, 10, 11], mais un syn- dr6me rectal a succ6d6 ~ la ddcouverte de 5 des 21 cas

176 V o l u m e 25 - N ~ 2 - 1995 A c t a E n d o s c o p i c a

de Jonas. Notre pa t ien t souffrait d ' u n e diarrh6e prd- cddant de deux mois la coloscopie. Le pat ient de Ben Re jeb a prdsent6 d ' a b o n d a n t e s rec torragies sponta- rides. Darts ces deux observat ions , le lien entre symp- t6mes et pseudo l ipomatose para~t pou r t an t b ien rdel car la dispar i t ion des signes fonc t ionne ls s ' accompa- gnait d ' u n e gudrison histologique. Dans no t re obser- vation, le facteur ddclenchant ia trog~ne s 'av6re bien discutable, d ' a u t a n t que la r6gression des sympt6mes , h a b i t u e l l e m e n t que lques sema ines apr~s l ' endosco- pie incr iminde, a 6t6 beaucoup plus lente.

CONCL USION

La p s e u d o l i p o m a t o s e m u q u e u s e co l ique est une ent i t6 h i s t o l o g i q u e m e n t p a r f a i t e m e n t d6finie. Sa na ture ia t rogene est parfois manifeste : colite au per- oxyde d 'hydrogOne, ba r o t r a uma t i sme endoscopique . Sa symp t oma t o l og i e protOiforme, l ' ex is tence de cas spontands inci tent ~t envisager le caract6re plurifacto- riel de cette affection au demeuran t bdnigne, 5 l ' image des multiples causes de la pneumatose kystique.

REFERENCES

1. BEN REJEB A., KHEDHIRI F. - - La pseudolipomatose muqucuse du colon. A propos d'une observation avec revue de la littOrature. Arch. Anat. Cvtol. Pathol,, 1989, 37 (5, 6), 254 -7.

2. COX M.E. , BOSTWICK D.G. - - Mucosal plaques seen at colonoscopy: chemical colitis or mucosal pseudolipomatosis. Gastroenterology, 1989, 96 (6), 1626-7.

3. GAGLIARDI G., HERSHMAN M.J., THOMPSON I.W., JORDAN S., HAWLEY P.R., TALBOT I.C. - - Pneumatosis colt. A review of 25 cases. Gut, Spring Meeting, 24-26 March 1993 (Abstr.).

4. JONAS G., MAHONEY A., MURRAY J., GERTLER S.-- Chemical colitis due to endoscope cleaning solutions : a mimic of pseudomembranous colitis. Gastroenteroh;gy. 1988, 95, 1403-8.

5. J O N A S G . , M A H O N E Y A . , M U R R A Y J., G E R T L E R S. - - Gastroenterology, 1989. 96, 1627.

6. PIETERSE A.S., LONG A.S., ROWLAND R. - - The muco- sal changes and pathogenesis of pneumatosis cystoidcs intesti- nalis, ltum. Pathol. Lab. Med., 1985, 16, 683-8.

7. SNOVER D.C., SANDSTAD J., HUTTON S. Mucosal pseudolipomatosis of the colon. Am. J. Clin. Pathol., 1985, 84 (5), 575-580.

8. SNOVER D.C., BOND J. - - Gastroenterology, 1989, 96 (6), 1627.

9. SUAREZ V., CHESNER I.M.. PRICE A.B., NEWMAN J. - - Pneumatosis cystoides intcstinalis. Arch. Pathol. Lab. Med., 1989, 113, 898-9(/1.

10. WARING J.P., MANNE R.K,, WADAS D.D., SANOWSKI R.A. - - Mucosal pseudolipomatosis : an air pressure-related colonoscopy complication. Gastrointest. Endoscopy, 1989, 35 (2), 93-4.

1l. WARRING J.P., MANNE R.K., WADAS D.D. - - Gastro- enterology, 1989, 96 (6), 1626.

I N T R O D U C T I O N

Mucosal pseudolipomatosis of the large bowel is a rare complication o f colonoscopy. It is often asTmpto- matic, A hhough pathologic findings are typical endo- scopic .features are variable and the mechanism remains poorly understood. We report a case o f pseu- dolipomatosis of the rectosigmoid, discovered when a chronic diarrhoea was investigated, and where the implication of colonoscopy is doubtful.

C A S E H I S T O R Y

A 31-year-old man, without any previous history nor any toxic habits', complained o f suffering from a glairy daytime diarrhoea accompanied by colic pain over the past two months. His general condition was preserved. The clinical examination, the biological

workup o f this chronic diarrhoea and an echography o f the abdomen were normal, An ileocoloscopy (pre- pared with polyethylene glycol) only revealed a rectal tubular adenoma, which was resected with a diather- real loop. The rectum was not biopsied. Since the diarrhoea continued to persist, a short endoscopy, prepared with a Normacol | enema, was again carried out two months later. A l though the macroscopic appearance remained normal, staged biopsies o f the rectosigmoid disclosed intramucosaL optically empty vacuoles (Figure 1) resembling adipoo'tes. The epi- thelium and the crypts were normal. There were no associated vascular changes nor any submucosal pneumatosis. Without any treatment, the diarrhoea disappeared within three weeks. A check-up carried out eight months later did not reveal any signs o f recurrence. The diagnosis of a pseudolipomatosis o f the rectosigmoid was maintained. The part played by the colonoscopy, carried out two months before the diagnosis and which had not aggravated the symp- toms, is debatable.

Acta Endoscopica Volume 25 - N ~ 2 - 1995 177

D I S C U S S I O N

Mucosal pseudolipomatosis of the colon was repor- ted for the first time in 1985 by Snover et al. [7] after studying 24 cases. The authors had previously repor- ted cases of lipomatosis of the rectocolonic mucosa. Specific stains for fats (Red Oil O, Sudan black B), fur mucins (PAS), and ultrastructural [7, 10] as well as polarized light [10] studies proved the absence of adi- pocytes.

Microscopic features of this disorder are characte- ristic: presence of intramucosal, optically empty vacuoles (20 to 130 lam in size). These cystic areas force back the adjacent cells of the lamina propria, whose nucleus, at a tangent to the vacuole, can resemble adipocytes. Although there may be, some- times, a discrete pericystic collagenation, the surface epithelium, the blood vessels, the crypts and the glands are unharmed, and the submucosa is intact.

Macroscopic features are equivocal. The mucous membrane of our patient was normal. Ben Rejeb [1] reported a soft and regular axial stenosis o f the sig- moid, bringing to mind a lymphangioma or a fatty tumour. The classic features, however, are superficial or barely raised, white or yellowish plaques, which may be single or multiple, with sizes ranging from mil- limeters to centimeters, and bearing a resemblance to pseudomembranes [4, 7, 10] on a discretely or inten- sely erythematous background [8].

The Pathogenesis o f the disorder remains contro- versial: Jonas [4] found the mucous membrane to be macroscopically normal in 20 cases, when the endo- scope was first introduced, with lesions appearing during the examination. The disinfection procedure of the endoscope (10 minute irrigation of the operating channels with 3 % hydrogen peroxide) was called into question. The author reported that all cases (except one) returned to normality when this procedure was abandoned. The oxidising proerties of hydrogen per- oxide, creating effervescence, could explain the obser- ved phenomenon. The chemical colics following a soapsuds enema, or one with added hydrogen per- oxide, reproduce this mechanism, just as an irrigation with peroxide of a murine colon produced the same effect within a minute; histological vacuolar features were then observed.

On the other hand, other authors, among whom Snover, have never employed similar disinfection pro- cedures. A contamination of the operating channels by glutaraldehyde has been envisaged [4, 5], all the more that cases of pseudolipomatosis occurred mostly towards the end of an endoscopic examination. The

low incidence of this disorder - 0.3 to 1.7 % of colono- scopies [4, 7, 10] - argues against this hypothesis, as does the case reported by Ben Rejed where the patient had never previously undergone a rectoscopy [1].

As to Waring [10], who reported 4 cases, the lesions were present right at the beginning of the first endo- scopy. The explanation which was given was a trans- epithelial release of intraluminal gas by iatrogenic barotrauma. In a healthy mucosa, the gas remains intromucosal whereas in an affected mucosa, it dif- fuses towards the submucosa [6, 8, 11]. The association of a pseudolipomatosis and a cystic pneumatosis is not infrequent (5 cases out of 25 found by Gagliardi [3] and 3 cases out of 10 for Suarez [9]) and gives some support to the exploratory technique since, as Snover and Cox [2] point out, some experienced endoscopists have never observed it, but this is refuted by Jonas [5]. However, all attempts to reproduce a pseudolipomato- sis on corpses by insufflation or parietal colonic instil- lation of gas have failed [7, 10] and so this mechanism does not explain everything.

The symptoms, which are very variable, do not per- mit to date the onset nor establish the chronology of the disorder with regard to an endoscopy. Most of the reported cases were discovered accidentally during screening endoscopies [7, 10, 11], but a rectal syn- drome followed the discovery in 5 of the 21 cases reported by Jonas. Our patient had a chronic diar- rhoea for two months before undergoing colonoscopy while Ben Rejeb's patient suffered from abundant spontaneous proctorrhagias. In these two cases, a link between the symptoms and pseudolipomatosis seems therefore to be genuine because the disappearance of the functional symtpoms was accompanied by a histo- logical recovery. In our case, the iatrogenic triggering factor is very debatable, and all the more so that the regression of the symptoms, usually lasting a few weeks after the incriminated endoscopy, took conside- rably longer.

C O N C L U S I O N

Pseudolipomatosis of the colonic mucosa is a well- defined histological entity. The iatrogenic nature is sometimes quite undeniable: hydrogen peroxide coli- tis, endoscopic barotrauma... Its protein symptomato- logy, the existence of spontaneous cases prompts to take into consideration the multifactoriat nature of this disorder, albeit benign, just like the multiple causes of cystic pneumatosis.

178 Volume 25 - N ~ 2 - 1995 Acta Endoscopica