Xanthogranulomatous pyelonephritis with nephrocutanous fistula and coexisting renal replacement lipomatosis

Renal Replacement Lipomatosis Presenting in the Setting of Ureteral Stricture with Absence of Renal Calculus Disease

Renal replacement lipomatosis of the kidney is a rare, benign entity in which extensive fibrofatty proliferation of the renal sinus is associated with marked atrophy of the renal parenchyma. It is often associated with calculi or long-standing inflammation. This entity may be confused with a fatty neoplasm of the kidney. A 51-year-old woman with a past medical history of pancreas transplant for type 1 diabetes subsequently developed ureteral stricture. This was initially managed by a nephrostomy tube and nephroureterostomy stenting with periodic exchanges to help restore urine flow; however, the renal function of the kidney progressively declined with recurrent and complicated urinary tract infections. She presented for kidney transplant with right native nephrectomy. Gross examination of the right kidney revealed a 12.8 cm renal sinus lipomatous mass replacing much of the kidney. Microscopically, the mass consisted of mature adipose tissue with fibrous septae and occasional thick-walled vessels with prominent smooth muscle bundles. A rare atypical stromal cell was present, otherwise no significant cytologic atypia or lipoblasts were identified. After excluding fat-predominant angiomyolipoma and well-differentiated liposarcoma, a diagnosis of renal replacement lipomatosis was made. Renal replacement lipomatosis is a benign condition typically associated with a nonfunctioning or poorly functioning kidney often linked to renal calculus disease or chronic renal infection. The presentation in our case was atypical given an absence of associated renal calculus disease. This case is intended to increase awareness of this less commonly encountered entity as it may be confused with a fatty neoplasm of the kidney, some with malignant potential.

Renal replacement lipomatosis: A rare type of renal pseudotumor

Replacement lipomatosis of the kidney is the end result of severe atrophy of renal parenchyma with secondary marked proliferation of renal sinus and perirenal fatty tissue. Although ultrasonography may suggest the diagnosis, CT demonstrated the distinctive features most accurately. We report a case of renal replacement lipomatosis with coexistent xanthogranulomatous pyelonephritis and multiple perinephric and parietal wall collections.

MRI appearance of massive renal replacement lipomatosis in the absence of renal calculus disease

Renal replacement lipomatosis is a rare benign entity in which extensive fibrofatty proliferation of the renal sinus is associated with marked renal atrophy. In this report, we present a case of massive renal replacement lipomatosis demonstrated on MRI. The presentation was atypical given an absence of associated renal calculus disease, and an initial CT scan was interpreted as suspicious for a liposarcoma. The differential diagnosis and key MRI findings that served to establish this specific diagnosis are reviewed. Histopathological correlation is also presented, as the patient underwent nephroureterectomy.

Cause of internal hemorrhage determined after exhumation: Report of one case

A 36-year-old woman consulted the medical emergency unit of a private health center for abdominal pain and gastroenteritis of 5 days duration. Acute right pyelonephritis was diagnosed. Five hours after admission she became unconscious in a state of clinical shock. She was transferred to an intensive care unit but resuscitation attempts were unsuccessful and she died 3h later. Three days after death, she was buried in the family vault. Five days after the burial, her husband lodged a complaint with the public prosecutor because he had not received a clear explanation from the physicians concerning the cause of his wife's death. After analysis of the medical records of the deceased by two forensic pathologists, a medicolegal autopsy was ordered by the public prosecutor. The corpse was exhumed and autopsy performed 9 days after death. Massive hemoperitoneum was diagnosed with a macroscopically ruptured subcapsular hematoma. Pathological study confirmed acute right pyelonephritis and demonstrated the precise cause of the hemorrhage: rupture of the hepatic artery at the hilar part, following infectious arteritis which was probably secondary to the acute pyelonephritis. To the best of our knowledge, this is the first published report of such a case.

Renal replacement lipomatosis

We report a relatively rare case of renal replacement lipomatosis presenting as a renal mass. Computed tomography revealed a predominantly low-density and roundish mass, with an irregular renal parenchyma, high-density calcification, and abundant low-density fat. The differential diagnosis before surgery was squamous cell carcinoma, teratoma, or angiomyolipoma of the kidney. The case was initially misdiagnosed, because we had no experience with this disease. After mass exploration, histological examination confirmed the diagnosis of renal replacement lipomatosis. The patient was free from signs of recurrence 10 months after the operation.