02580nas a2200457   4500000000100000008004100001260001300042653001900055653001000074653001100084653002000095653001600115653002000131653001400151653002800165653002000193653001600213653001800229653001100247653002200258653001200280653002300292653001200315653001600327653000900343653002500352653001600377100002000393700001700413700001700430700001800447700002100465700002100486700001800507700001800525245010900543300001100652490000700663520143800670022001402108       2000                            d  c2000 Jan10aAbdominal pain10aAdult10aBiopsy10aChronic Disease10aClofazimine10aCrystallization10aCytoplasm10aDiagnosis, Differential10aFrozen Sections10aHistiocytes10aHistiocytosis10aHumans10aIntestinal Mucosa10aJejunum10aLeprostatic Agents10aleprosy10aLymph Nodes10aMale10aMicroscopy, Electron10aRadiography1 aSukpanichnant S1 aHargrove N S1 aKachintorn U1 aManatsathit S1 aChanchairujira T1 aSiritanaratkul N1 aAkaraviputh T1 aThakerngpol K00aClofazimine-induced crystal-storing histiocytosis producing chronic abdominal pain in a leprosy patient.  a129-350 v243 a<p>Clofazimine-induced crystal-storing histiocytosis is a rare but well-recognized condition in the literature. Besides the common reddish discoloration of the skin, clofazimine produces gastrointestinal disturbances-sometimes severe abdominal pain, prompting exploratory laparotomy, because pathologic and radiologic findings can produce diagnostic difficulties if the pathologic changes caused by clofazimine are not recognized. The authors report such a case in a leprosy patient to emphasize the importance of history taking, the radiologic abnormalities of the small intestine, and the pathologic findings in small intestine and lymph node biopsies. Clofazimine crystals are red in the frozen section and exhibit bright-red birefringence. However, they are clear in routinely processed histologic sections because they dissolve in alcohol and organic solvents. They also appear as clear crystal spaces during electron microscopic study, but some osmiophilic bodies can be observed. Histiocytosis caused by clofazimine crystals produces infiltrative lesions in radiologic studies mimicking malignant lymphoma or other infiltrative disorders. Associated plasmacytosis in the histologic sections can simulate lymphoplasmacytic lymphoma or multiple myeloma with crystal-storing histiocytosis. With the knowledge of this rare condition caused by clofazimine, appropriate management to avoid an unnecessary laparotomy is possible.</p>  a0147-5185