British Journal of Radiology (2005) 78, 450-452
© 2005 British Institute of Radiology
doi: 10.1259/bjr/62643156
Bilateral multilocular cystic nephromas: a rare occurrence
K S Sodhi, MD1,
S Suri, MD, DABR1,
R Samujh, MCh2,
K L N Rao, MCh, FACS, FAMS2,
K Vaiphei, MD3 and
A K Saxena, MD, DNB1
Departments of 1 Radiodiagnosis, 2 Pediatric Surgery and 3 Histopathology, Postgraduate Institute of Medical Education and Research, (PGIMER), Chandigarh – 160 012, India
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Abstract
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We present a rare case of bilateral renal cystic tumours in an 18-month-old female child, which proved to be cystic nephromas on imaging and histopathology. Although unilateral cystic nephromas are known in children; the occurrence of bilateral tumours is rare.
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Introduction
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Cystic nephroma, also called multilocular cystic nephroma is a rare renal neoplasm. Bilateral cystic nephromas are much rarer. In fact, unilaterality of the lesion was one of the eight initial diagnostic criteria proposed by Powell et al [1] and revised by Boggs and Kimmelstiel [2]. To the best of our knowledge, only 4 paediatric cases of bilateral cystic nephromas have been reported [3], including two cases with asynchronous involvement.
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Case report
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An 18-month-old female child presented with a complaint of a gradually increasing abdominal lump on the right side of the abdomen, present for the last 10 months. She had no history of fever, gastrointestinal or urinary complaints.
On examination, she was active, afebrile, well built, with a normal pulse, respiratory rate and blood pressure. Laboratory tests were normal with a creatinine of 1.0 mg dl–1. Abdominal examination revealed a large, firm, smooth, mobile, cystic, non-tender mass in the right lumbar region, which crossed the midline. The left flank was normal. Ultrasound of the abdomen (Figure 1
) and CT (Figure 2a,b), revealed the presence of large, well circumscribed, multiloculated, purely cystic masses, in both lumbar regions, arising from both kidneys. There was no evidence of calcification or fat within the lesions. The right sided mass compressed the head of the pancreas, the liver, gallbladder and spleen were normal, and there was no ascites or abdominal lymphadenopathy. Based on CT scan, diagnosis of cystic nephromas was made. The patient underwent bilateral partial nephrectomies. Histopathological examination of the resected tumours revealed numerous varying sized cystic structures, lined by flattened to low cuboidal cells, with intervening septae showing proliferating fibroblasts, thin walled vessels, lymphoid aggregates and few flattened tubules and glomeruli. No blastemal nodules or solid areas were seen. The histological diagnosis was of bilateral multilocular cystic nephromas.
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Figure 1. Ultrasound abdomen of an 18-month-old girl reveals a multiseptate cystic mass in the left hypochondrium.
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Figure 2. (a) Coronal and (b) axial contrast enhanced CT abdomen of the same patient showing bilateral, cystic, multiseptate renal masses.
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Discussion
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Bilateral renal cystic tumours in children are an uncommon group of tumours and include cystic wilms tumour, renal lymphangiomatosis, tuberous sclerosis complex, cystic nephroma and cystic poorly differentiated nephroblastoma.
Of these, tuberous sclerosis complex consists of multiple angiomyolipomas and cysts, while renal lymphangiomatosis consists of multiple perirenal and parapelvic cysts. Both these entities can be easily diagnosed on imaging. The other three entities; cystic wilms tumour, cystic nephroma and cystic poorly differentiated nephroblastoma are less easily differentiated on imaging.
Cystic nephroma is an uncommon renal neoplasm, initially thought to only occur unilaterally. Powell et al [1] established eight diagnostic criteria for these lesions: unilateral involvement; solitary lesion; multilocular lesion; non-communication with the renal pelvis; non-communication of the cysts with each other; loculi lined by epithelium; intralocular septa devoid of renal parenchyma; and if residual renal tissue were present, it should be normal. Of these criteria, one was modified by Boggs and Kimmelstiel [2], several years later to include the presence of immature renal tissue in the intervening septa. These criteria have remained largely unchanged over the years, although more recently some authors have proposed the elimination of unilaterality as a diagnostic criteria [3].
Multilocular cystic renal tumours refer to two types of generally benign renal tumours: cystic nephroma (CN) and cystic poorly differentiated nephroblastoma (CPDN) [4, 5], although the other end of the spectrum does include cystic wilms tumours. These are well circumscribed, discrete lesions consisting entirely of cysts and septae, without solid tumour components except for the septae. These tumours generally follow a benign course; nephrectomy alone is usually curative, with rare local recurrences effectively managed by local radiation or chemotherapy.
These tumours usually present as an abdominal mass, in a young child between the ages of 3 months and 4 years [6]. The mass may slowly increase in size or may demonstrate rapid growth. Systemic symptoms are uncommon.
Cystic nephroma and cystic poorly differentiated nephroblastoma are indistinguishable on gross examination as well as on imaging. The masses are often large, averaging 8–10 cm in size and are single, unilateral, and involve only part of the kidney [4]. There is no communication between cysts or with the collecting system. Septae in CN are fibrous and may contain well-differentiated tubular structures; poorly differentiated tissues and blastemal cells are absent in the septae of CN. CPDN resembles CN in every feature except that the septae in CPDN contain blastemal cells with or without other embryonal stromal cells. It is important to note that that there are no solid elements (other than septae) in this lesion, differentiating the entity from wilms tumour and other renal neoplasms, which may contain cystic spaces owing to haemorrhage and necrosis [7].
Radiologically, plain film findings may demonstrate a soft tissue mass with displacement of bowel loops. Ultrasound demonstrates a complex intrarenal mass with acoustic enhancement. Septations, dividing the mass into discrete sonolucent locules, may be seen if the cysts are of sufficient size. When individual cysts are small however, ultrasound may demonstrate numerous internal echoes but no distinct loculations [6]. The findings of a peripheral crescentic rim of renal collecting system, is helpful to confirm the renal origin of the tumour. On CT, a sharply circumscribed, multiseptated mass is demonstrated, with cystic spaces between septae. The contents of the cysts may be similar to or slightly greater than water attenuation. In some tumours the cystic spaces are very small, resulting in the appearance of a solid soft tissue mass. Enhancement of septae may be seen following intravenous contrast; however, no filling of cystic spaces with contrast occurs [6]. MRI demonstrates an encapsulated multilocular renal mass, with the capsule showing low signal intensity on all pulse sequences, variable signal intensity of cyst contents on T1 weighted images, and high signal intensity of cyst contents on T2 weighted images [4]. All cases of CN follow a benign course and renal sparing surgery is the optimal treatment described for this lesion [3].
However, CPDN may demonstrate more aggressive behaviour with a potential for recurrence following resection. Since these two entities cannot be distinguished by imaging or by gross appearance, the treatment is complete surgical resection, with non-invasive imaging for follow-up if the tumour proves to be CPDN.
In conclusion, although cystic nephromas in children are more commonly unilateral, they may also rarely occur bilaterally and need to be differentiated from other cystic renal tumours of childhood.
Received for publication September 13, 2004.
Accepted for publication January 17, 2005.
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References
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- Powell T, Shackman R, Johnson H. Multilocular cysts of the kidney. J Urol 1951;23:142–52.
- Boggs LK, Kimmelstiel P. Beningn multilocular cystic nephroma: a report of two cases of so-called multilocular cyst of the kidney. J Urol 1956;76:530–41.[Medline]
- Ferrer FA, McKenna PH. Partial nephrectomy in a metachronous mutlilocular cyst of the kidney (cystic nephroma). J Urol 1994;151:1358–60.[Medline]
- Geller E, Smergel EM, Lowry PA. Renal neoplasms of childhood. Radiol Clin North Am 1997;35:1391–413.[Medline]
- Joshi V, Beckwith JE. Multi locular cyst of the kidney (cystic nephroma) and cystic, partially differentiated nephroblastoma. Cancer 1989;64:466–79.[CrossRef][Medline]
- Madewell J, Goldman S, Daris C, et al. Multilocular cystic nephroma: a radiographic pathologic correlation of 58 patients. Radiology 1983;146:309–21.[Abstract/Free Full Text]
- Agrons G, Wagner B, Davidson A, et al. Multi locular cystic renal tumour in children: radiologic-pathologic correlation. Radiographics 1995;15:653–69.[Abstract]
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Abstract
Introduction
