[1 case per day of PHILIPS] Imaging manifestations of renal epidermoid cysts in 1 case

Renal epidermoid cysts are clinically rare and easy to misdiagnose before surgery, and the clinical and imaging data of a case of renal epidermoid cyst confirmed by surgical pathology are analyzed in this paper, and combined with the literature to improve the understanding of

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The patient, a 30-year-old male, began to develop upper abdominal distention and malaise 1 month ago, without nausea, vomiting, fever, diarrhea, and no melancholy and clay stools

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Routine bowel preparation, fasting, oral warm boiled water 300 ml before examination, using Toshiba Aquilion 16-layer multi-row spiral CT scanner

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A huge cystic mass can be seen in the right renal region, about 7 cm ×12 cm in size, the wall is thin, the inner separation is visible, the inner and posterior walls are slightly thickened, the thickened medial wall is partially seen with punctate calcium spots, the water-like density of the cystic fluid, the flocculents of the inner visible flakes are slightly higher, a nodule and the thickened posterior wall broad group (Fig.

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A very large cystic mass on the medial side of the right kidney, dark red, with a heavy adhesion to the peritoneum, the mass originated from the right kidney, and the electric hook cut through the sac wall, and a large amount of yellow-white viscous paste flowed out

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There are many theories about the etiology of epidermoid cysts, which are roughly divided into two categories: congenital and acquired, congenital is the development of the skin ectoderm remaining when the early neural groove is closed, and the acquired one is mostly trauma surgery that brings the epidermis into deep tissues and continues to proliferate and grow, and is more common in the fingers, palms, plantars or surgical

Epidermoid cysts mostly occur on the surface of the body, rarely occur in solid organs, renal epidermoid cysts are rare in clinical practice, and there are few similar cases reported at home and abroad, among which scholars have proposed that kidney and ureter epidermoid cysts may be caused by epithelial cell metaplasia caused by stone stimulation after injury to epithelial cells caused

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The disease is more common in patients aged 30 to 40 years, the ratio of men to women is 1.

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3 Image representation

Imaging is the mainstay of the diagnosis and differential diagnosis of cystic lesions in vivo, and correct diagnosis provides guidance for treatment planning and follow-up, but imaging reports of renal epidermoid cysts are rare and are mostly reported
in cases 。 Reviewing the literature and the case data of this case, the imaging manifestations of epidermoid cysts are summarized as follows: typical CT of epidermoid cysts is characterized by water-like density of intracystic fluid, smooth edges, thin and uniform sac walls, in some rare cases, intracyscapsular separation, uneven thickening of cyst walls, occasional calcium spots, high-density clumps or flocculents visible in the capsule, no strengthening or mild strengthening of the cyst wall and separation of lesions after injection, and no strengthening
of cystic fluid and cyst contents.

In this case, the right renal epidermoid cyst shows a large separating cystic mass, the inner and lower wall is unevenly thickened, the density in the capsule is uneven, high-density nodules and flocculents are visible, the cyst wall and separation are mildly strengthened after injection, and the cyst fluid and contents are not significantly strengthened, which is consistent
with the literature report.

MRI shows that the contents of the epidermoid cyst are more advantageous than CT, the amorphous mass in the cystic fluid, cloud flocculent or nodular keratides, the high and low mixed signals on T2WI, T1WI is equal or slightly higher signal, because the capsule contains colloidal detritus, solid cholesterol crystals and other lipids, etc.
, keratinized squamous epithelial cells continue to shed and disintegrate products, so the DWI is high signal, the presence of these keratins, so that the MRI performance of epidermoid cysts has certain characteristics; In addition, MRI also has obvious advantages in the localization and diagnosis of tumors, which can clearly show the relationship between the mass and the surrounding adjacent organs and whether there is adhesions, etc.
, which has important clinical significance for guiding surgery, and MRI can be used as the optimal examination method for epidermoid cysts
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According to the CT manifestations of the lesion in this case, the differential diagnosis should include the following cystic lesions: 1) Renal cysts: the cyst wall of the simple renal cyst lesion is thin, smooth and clear, rounded, the density is uniform and the CT value is < 20Hu, the MRI is uniformly long T1 long T2 signal shadow, bleeding or infected renal cysts can be separated, the density within the cyst is increased, the signal is complex, the cyst wall may be calcified, but the enhanced scan is still not strengthened; 2) Cystic kidney cancer: round or oval, the cyst wall is thin, the edges are smooth, the surrounding solid components are often visible, the wall nodules and separations are enhanced, and the wall nodules and intervals are more than moderately strengthened; 3) Cystic teratoma: because the sac contains lipid component T1WI can see high signal, typical can see the "float sign", lipid level sign can also contain teeth, calcification and bone components, it is not difficult to identify; 4) Renal echinococcosis: often combined with hepatic and pulmonary echinococcosis, the calcification of the cyst wall is thicker ring or lumpy, the small cysts of different degrees can be seen in the large sac, the sac wall is strengthened after enhancement, combined with clinical laboratory tests and whether the patient is from the epidemic area, it can be used to identify epidermoid cysts as a benign disease, but its malignant rate into squamous cell carcinoma is 0.
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045%, there are reported 16 cases of epidermoid cyst malignancy into squamous carcinoma, including skull, head and neck and thighs, Gu Zhiming and others have reported 1 case of malignancy of left kidney epidermoid cyst, Treatment of this lesion is preferably surgical resection, which is aimed at complete removal of the mass to prevent residue and the possibility
of recurrence.