The sonographic appearance of milk of calcium in renal caliceal diverticuli

Abstract

A collection of milk of calcium in a caliceal diverticulum is an unusual finding with benign clinical implications. Only one case' has been reported demonstrating the sonographic features of milk of calcium in a caliceal diverticulum, although the conventional urographic appearance has been well documented. We have added a second case which confirms the previously described sonographic findings of gravity-dependent, echogenic, shadowing material in a cystic renal lesion. Our case is unique in that we discovered bilateral caliceal collections of milk of calcium. The literature on milk of calcium is briefly reviewed. CASE REPORTA 25-yr-old woman presented to the Massachusetts General Hospital with right upper quadrant pain and a temperature of 100.4"F. On physical examination, there was right upper quadrant pain but no flank tenderness. The leukocyte count was 11,400, with no left shift. The laboratory chemistry values of Ca2+, PO4, blood urea nitrogen, creatinine, bilirubin, serum glutamic-oxaloacetic transaminase , and serum glutamic-pyruvic transaminase were normal. On urinalysis, a few amorphous crystals were noted in the sediment. There was no pyuria, bacteriuria, or hematuria. Urine cultures were negative. The pH was 6.5, and the specific gravity was 1.009.A preliminary film of the abdomen revealed opacifications in the right and left upper quadrants overlying the renal shadows, suggesting calculi. On the upright film, the calcifications formed a linear collection on the right and a meniscus-like "half-moon" collection on the left, (Fig 1A). An oral cholecystogram showed good opacification of the gallbladder and no evidence of stones.Abdominal ultrasound examination was performed using an ATL scanner* with a 3.5-MHz transducer. The supine real-time scans demonstrated right and left upper pole cystic lesions with enhanced through transmission. There were gravity-dependent, dense internal echoes with minor acoustic shadowing (Fig lC, D). On nephrotomography, the lesions did not opacify ( Fig 1B).The patient's symptoms resolved after two days, and she was discharged without a diagnosis of her right upper quadrant pain. DISCUSSIONThe sonographic appearance of milk of calcium within a caliceal diverticulum was first reported by Schabel et all in 1980. Our case confirms his findings of gravity-dependent echogenic material in a cystic renal lesion with low-grade shadowing. Although a reasonable differential diagnosis might include calculi within a hydrocalyx, the sonographic features of this entity appear diagnostic.The radiographic manifestations of milk of calcium in a caliceal diverticulum were first discussed by Fresnais2 and described in the English literature by H~w e l l .~ Characteristically, a meniscus or calcium-fluid level is seen on horizontal beam projections but is not appreciated en face. Since ultrasound has a well-documented capacity to image renal cystic lesions and stones surrounded by fluid, it should also be sensitive in diagnosing this condition.milk of calcium occurred with equal frequency i...

Pyelocalyceal diverticulum: the imaging spectrum with emphasis on the ultrasound features

“…In one of them, an additional linear calcification was seen in the lesion (case 8). Connection with the collecting system was demonstrated on delayed images in 2 cases (cases 8,9) (Figures 5b-d).…”

“…Recognition of mobile echogenic material within such a cyst-like structure is considered characteristic of milk of calcium [3,4,8]. A cyst-like mass with milk of calcium is presumed to be a PCD [8].…”

“…Recognition of mobile echogenic material within such a cyst-like structure is considered characteristic of milk of calcium [3,4,8]. A cyst-like mass with milk of calcium is presumed to be a PCD [8]. When echogenic material is found within a cyst-like mass it is therefore important to scan in different positions to demonstrate the [3,4].…”

Renal cyst completely filled with milk of calcium on ct appears as a simple cyst on sonography

“…The communication that exists with the renal collecting system is usually very narrow and may be obliterated. 1,2 Proposed underlying causes for the development of calyceal diverticula include abnormal branching of the ureteric buds and developmental defect of Wolffian ducts. 2,3 Alternative explanations include rupture of renal cyst into the collecting system, as a result of infection, and from passage of a stone.…”

“…3 Reported constituents of milk of calcium include calcium carbonate, calcium oxalate, calcium phosphate, ammonium phosphate, and calcium hydroxyapatite, among others. 1,3 Renal cysts with milk of calcium typically have layering echogenic material in their dependent aspect, variable acoustic shadowing, and reverberation echoes. 2 In one study acoustic shadowing in cysts containing milk of calcium was dependent on the size of the mass, with no acoustic shadowing for lesions less than 0.6 cm, but present to varying degrees in larger lesions.…”