bilirubin in hyperbilirubinemia or hemosiderin in hemochromatosis, or exogenous pigments such as heavy metals can be introduced into the mucosa, e.g. in an amalgam tattoo. Almost all white patches are benign, i.e. non-malignant. The differential diagnosis of a white lesion in the mouth can be considered according to a surgical sieve (see table).Leukoplakia cannot be rubbed off the mucosa, distinguishing it readily from white patches such as pseudomembraneous candidiasis, where a white layer can be removed to reveal an erythematous, sometimes bleeding surface underneath. The white color associated with leukoedema disappears when the mucosa is stretched. A frictional keratosis will generally be adjacent to a sharp surface such as a broken tooth or rough area on a denture and will disappear when the causative factor is removed. Some have a suggested as general rule that any lesion that does not show signs of healing within 2 weeks should be biopsied. Morsicatio buccarum and linea alba are located at the level of the occlusal plane (the level at which the teeth meet). A chemical burn has a clear history of placing an aspirin tablet (or other caustic substance such as eugenol) against the mucosa in an attempt to relieve toothache. Developmental white patches usually are present from birth or become apparent earlier in life, whilst leukoplakia generally affects middle aged or elderly people. Other causes of white patches generally require pathologic examination of a biopsy specimen to distinguish with certainty from leukoplakia.
Type I – No fistula present

Type IA – Presence of the cystic duct
Type IB – Obliteration of the cystic ductTypes II–IV – Fistula present

Type II – Defect smaller than 33% of the CHD diameter
Type III – Defect 33–66% of the CHD diameter
Type IV – Defect larger than 66% of the CHD diameter

Diagnosis
Imaging by ultrasonography, MRCP, or CT scan usually make the diagnosis. MRCP can be used to define the lesion anatomically prior to surgery. Occasionally Mirizzis syndrome is diagnosed or confirmed on ERCP when requested to alleviate obstructive jaundice or cholangitis by means of an endoscopically placed stent, or when USS has been wrongly reported as choledocolithiasis. Treatment
Simple cholecystectomy is suitable for type I patients. For types II–IV, subtotal cholecystectomy can be performed to avoid damage to the main bile ducts. Cholecystectomy and bilioenteric anastomosis may be required. Roux-en-Y hepaticojejunostomy has shown good outcome in some studies. Epidemiology
Mirizzis syndrome occurs in approximately 0.1% of patients with gallstones. It is found in 0.7 to 2.5 percent of cholecystectomies.It affects males and females equally, but tends to affect older people more often. There is no evidence of race having any bearing on the epidemiology. Eponym
It is named for Pablo Luis Mirizzi (1893–1964), an Argentinian physician. Mirizzi was educated and trained in his hometown and later visited some of the best hospitals throughout the United States for further education and training. Mirizzi specialized in abdominal and thoracic surgery and would write prolifically on related surgical topics. References


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