title: Milk of calcium stones: radiological signs and management outcome.
abstract: Milk of calcium (MOC) is a rare type of stone that was first described in 1940 by Ludin and Howald who reported MOC in renal cysts. Milk of calcium is a viscous colloidal suspension of calcium salts. Stasis, obstruction and infection are important predisposing factors. Due to a layering effect, characteristic radiological signs especially in CT can help in diagnosis to avoid unsuccessful shock wave lithotripsy. This is the largest reported case series, in which radiological signs by CT scan to predict renal MOC stones, clinical picture and management outcome are described in detail. Cases with suspected renal milk of calcium stones were studied over 7 years (2008-2015). All cases were diagnosed preoperatively by non-contrast CT. Urine cultures were performed in all patients preoperatively. Intra-operative and postoperative findings were reported. Stones retrieved were sent for chemical analysis using an infrared method. Seven cases of milk of calcium renal stones were included in this study. These stones were faint radio-opaque in two cases and radiolucent in five cases. All cases were diagnosed preoperatively with non-contrast CT. Their Hounsfield units (HU) ranged from 114 to 612. All stones were located in a dependent position (gravitational effect) in the posterior aspect of dilated calyces. Five cases exhibited the typical fluid level and two cases demonstrated semilunar (half moon) pattern in the anterior surface of the stones. All cases underwent PCNL with suction and retrieval of soft stones without the need for disintegration. When stones demonstrate a low Hounsfield unit, are arranged in dependent positions within dilated calyces and exhibit fluid level or semilunar pattern on non-contrast CT, milk of calcium stones should be considered. PCNL is an effective modality for management of renal milk of calcium stones.
authors.affiliation: Urology Department, Menoufia University, Shebin El-Kom, Egypt, mshazly2001@yahoo.com.
authors.forename: M
authors.initials: M
authors.lastname: El-Shazly
mesh_terms: D000328:Adult; D000368:Aged; D002119:Calcium Carbonate; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging* / Q000628:therapy; D008875:Middle Aged; D011859:Radiography; D016896:Treatment Outcome
chemical_list: D002119:Calcium Carbonate
references.citation: J Urol. 1985 Jan;133(1):77-8
references.pmid: 3964883
references.citation: Minerva Urol Nefrol. 1994 Jun;46(2):133-6
references.pmid: 7974086
references.citation: Br J Radiol. 2008 Feb;81(962):e35-6
references.pmid: 18238910
references.citation: Ann Urol (Paris). 1990;24(7):552-7
references.pmid: 2291644
references.citation: JRSM Open. 2014 Jun 09;5(7):2054270414533324
references.pmid: 25057410
references.citation: J Urol. 1980 Jan;123(1):1-8
references.pmid: 6766192
references.citation: Int J Urol. 2006 Aug;13(8):1109-11
references.pmid: 16903938
references.citation: Spinal Cord. 2000 May;38(5):325-6
references.pmid: 10822407
references.citation: Cent European J Urol. 2012;65(3):170-3
references.pmid: 24578958
references.citation: Urol Int. 1993;51(3):171-6
references.pmid: 8249230
references.citation: Hinyokika Kiyo. 1990 Dec;36(12):1447-50
references.pmid: 2127507
references.citation: Urology. 2011 Mar;77(3):596-7
references.pmid: 20708780
references.citation: Tech Urol. 1996 Summer;2(2):102-7
references.pmid: 9118405
references.citation: Urol Int. 1998;60(1):62-5
references.pmid: 9519425
references.citation: Urology. 1992 Aug;40(2):149-51
references.pmid: 1502752
references.citation: Arch Ital Urol Androl. 1996 Dec;68(5 Suppl):111-5
references.pmid: 9162340