A cystic nephroma, also known as multilocular cystic nephroma, mixed epithelial stromal tumour (MEST) and renal epithelial stromal tumour (REST), is a type of rare

benign Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

kidney tumour Kidney tumours are tumours, or growths, on or in the kidney. These growths can be benign or malignant ( kidney cancer). Presentation Kidney tumours may be discovered on medical imaging incidentally (i.e. an incidentaloma), or may be present in pa ...

Symptoms

Cystic nephromas are often asymptomatic. They are typically discovered on

medical imaging Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to revea ...

incidentally (i.e. an

incidentaloma In medical or research imaging, an incidental imaging finding (also called an incidentaloma) is an unanticipated finding which is not related to the original diagnostic inquiry. As with other types of incidental medical findings, they may represe ...

Diagnosis

Cystic nephromas are diagnosed by

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, an interventional radiologist, or an interventional cardiology, interventional cardiologist. The process involves the extraction of sampling (medicine), sample ...

or excision. It is important to correctly diagnose them as, radiologically, they may mimic the appearance of a

renal cell carcinoma Renal cell carcinoma (RCC) is a kidney cancer that originates in the lining of the Proximal tubule, proximal convoluted tubule, a part of the very small tubes in the kidney that transport primary urine. RCC is the most common type of kidney cance ...

that is cystic.

Pathologic diagnosis

The characteristics of cystic nephromas are: *

Cyst A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubb ...

s lined by a simple epithelium with a ''hobnail morphology'', i.e. the nuclei of the cyst lining epithelium bulges into the lumen of the cysts, * Ovarian-like stroma that has a: **Spindle cell morphology, and has a **Basophilic

cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...

. Cystic nephromas have an immunostaining pattern like ovarian stroma; they are positive for: * Estrogen receptor (ER), * Progesterone receptor (PR) and *

CD10 Neprilysin (; also known as membrane metallo-endopeptidase (MME), neutral endopeptidase (NEP), cluster of differentiation 10 (CD10) and common acute lymphoblastic leukemia antigen (CALLA)) is an enzyme that in humans is encoded by the ''MME'' ge ...

Differential diagnosis

Renal tumors by relative incidence and prognosis

* cystic partially differentiated nephroblastoma *cystic standard nephroblastoma (cystic Wilm's tumor) *cystic

mesoblastic nephroma Congenital mesoblastic nephroma, while rare, is the most common kidney neoplasm diagnosed in the first three months of life and accounts for 3-5% of all childhood renal neoplasms. It is generally non-aggressive and amenable to surgical removal, tho ...

*cystic

*other renal cysts

Additional images

Image:Cystic_nephroma_intermed_mag.jpg,

Micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...

of a cystic nephroma.

H&E stain Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin–eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diag ...

References

External links

{{Urologic neoplasia Benign renal neoplasms