Multilocular Cystic Tumor Research Articles

MP22-13 CLINICAL AND PATHOLOGIC CHARACTERISTICS OF EARLY ONSET RENAL CELL CARCINOMA

You have accessJournal of UrologyKidney Cancer: Epidemiology & Evaluation/Staging I1 Apr 2017MP22-13 CLINICAL AND PATHOLOGIC CHARACTERISTICS OF EARLY ONSET RENAL CELL CARCINOMA Win Shun Lai, Tyler Clemmensen, Ava Saidian, Soroush Rais-Bahrami, and Jennifer Gordetsky Win Shun LaiWin Shun Lai More articles by this author , Tyler ClemmensenTyler Clemmensen More articles by this author , Ava SaidianAva Saidian More articles by this author , Soroush Rais-BahramiSoroush Rais-Bahrami More articles by this author , and Jennifer GordetskyJennifer Gordetsky More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.667AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Based on studies from the SEER database, renal cell carcinoma (RCC) is considered early onset in adults ≤ 46 years of age. Limited data exists regarding patients with early onset RCC. Our objective was to investigate the clinical and pathologic characteristics within this unique subset of patients with RCC. METHODS We retrospectively reviewed our surgical pathology database from 2011-2016 for patients with RCC. The clinical and pathologic characteristics of patients ≤ 46 years were compared to the overall population. RESULTS We identified 98/604 (16%) cases of RCC in patients ≤ 46 years. The median age of patients with early onset RCC compared to our control group was 38.6 (range 19-46) vs. 64.4 (range 47-89) years, respectively. Early onset RCC patients included Caucasians (55%), African Americans (40%), Latino (4%), and Asian (1%). Histologic subtypes, included clear cell (54%), papillary (29%), unclassified (7%), chromophobe (5%), clear cell papillary (3%), multilocular cystic neoplasm (1%), and carcinoid (1%). 20/28 (71%) of early onset papillary RCCs occurred in African Americans. Risk factors for RCC included hypertension (47%), smoking (22%), obesity (12%), diabetes mellitus (9%), and chronic kidney disease (CKD) or end-stage renal disease (ESRD) (16.3%). Known genetic syndromes prior to diagnosis were identified in 7/98 (7%) patients (1 Von Hippel Lindau, 2 Familial Adenomatous Polyposis, 1 Marfan, 1 Tuberous Sclerosis, 1 Birt-Hogg-Dube). There was no significant difference between the two groups in terms of tumor size, focality, margin status, presence of necrosis, or sarcomatoid features. Non-Caucasians were more likely to develop early onset RCC (OR 1.98; p=0.001). Patients with early onset RCC were more likely to receive a radical nephrectomy (OR 1.98; p=0.001), have lower grade tumors (OR 0.69; p=0.033) and present with organ confined disease (p=0.008). CONCLUSIONS Despite having more indolent tumor characteristics and organ confined disease, early onset RCC patients were more likely to undergo a radical nephrectomy. In addition, a high percentage of these patients had either concurrent, or risk factors for developing, CKD/ESRD. These findings suggest that this population is potentially being over treated and should undergo nephron sparing surgery if surgically feasible. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e261-e262 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Win Shun Lai More articles by this author Tyler Clemmensen More articles by this author Ava Saidian More articles by this author Soroush Rais-Bahrami More articles by this author Jennifer Gordetsky More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Gene fusions PAFAH1B1–USP6 and RUNX2–USP6 in aneurysmal bone cysts identified by next generation sequencing

Aneurysmal bone cyst (ABC) is a locally aggressive, expansile, typically multilocular cystic bone tumor. ABC was previously thought to be a non-neoplastic lesion; however, it is now considered to be neoplasm that features recurrent chromosomal translocations resulting in gene fusions between ubiquitin specific peptidase 6 (USP6) and multiple partners, including COL1A1, CDH11, TRAP150, ZNF90 and OMD. Using next generation sequencing (NGS), we uncovered two fusion partners of USP6 in two ABCs: platelet activating factor acetylhydrolase 1b regulatory subunit 1 (PAFAH1B1), which is known to contribute to tumorigenesis in lung cancer, and runt-related transcription factor 2 (RUNX2), which is known to regulate osteoblastic differentiation, osteosarcoma tumorigenesis and its metastasis. In our study, the PAFAH1B1-USP6 fusion consisted of the promoter of PAFAH1B1 fused to the 5'-untranslated region (5'-UTR) of USP6 and was discovered in a typical ABC. The RUNX2-USP6 fusion had the promoter and a short coding region of RUNX2 fused to the translation start codon of USP6 and was detected in an unusually aggressive ABC with an osteosarcoma-like soft tissue extension. Our findings not only expanded the repertoire of the partner genes of USP6 in ABC but also can serve as a reference for future studies to better understand the correlation between various gene fusions and the progression of ABC.

Morphological, immunohistochemical, and chromosomal analysis of multicystic chromophobe renal cell carcinoma, an architecturally unusual challenging variant.

Chromophobe renal cell carcinoma (ChRCC) is typically composed of large leaf-like cells and smaller eosinophilic cells arranged in a solid-alveolar pattern. Eosinophilic, adenomatoid/pigmented, or neuroendocrine variants have also been described. We collected 10 cases of ChRCC with a distinct multicystic pattern out of 733 ChRCCs from our registry, and subsequently analyzed these by morphology, immunohistochemistry, and array comparative genomic hybridization. Of the 10 patients, 6 were males with an age range of 50-89years (mean 68, median 69). Tumor size ranged between 1.2 and 20cm (mean 5.32, median 3). Clinical follow-up was available for seven patients, ranging 1-19years (mean 7.2, median 2.5). No aggressive behavior was documented. We observed two growth patterns, which were similar in all tumors: (1) variable-sized cysts, resembling multilocular cystic neoplasm of low malignant potential and (2) compressed cystic and tubular pattern with slit-like spaces. Raisinoid nuclei were consistently present while necrosis was absent in all cases. Half of the cases showed eosinophilic/oncocytic cytology, deposits of pigment (lipochrome) and microcalcifications. The other half was composed of pale or mixed cell populations. Immunostains for epithelial membrane antigen (EMA), CK7, OSCAR, CD117, parvalbumin, MIA, and Pax 8 were positive in all tumors while negative for vimentin, TFE3, CANH 9, HMB45, cathepsin K, and AMACR. Ki67 immunostain was positive in up to 1% of neoplastic cells. Molecular genetic examination revealed multiple chromosomal losses in two fifths analyzable tumors, while three cases showed no chromosomal numerical aberrations. ChRCC are rarely arranged in a prominent multicystic pattern, which is probably an extreme form of the microcystic adenomatoid pigmented variant of ChRCC. The spectrum of tumors entering the differential diagnosis of ChRCC is quite different from that of conventional ChRCC. The immunophenotype of ChRCC is identical with that of conventional ChRCC. Chromosomal numerical aberration pattern was variable; no chromosomal numerical aberrations were found in three cases. All the cases in this series have shown an indolent and non-aggressive behavior.

A resected case of symptomatic acinar cell cystadenoma of the pancreas displacing the main pancreatic duct.

Acinar cell cystadenoma (ACA) of the pancreas has been newly recognized as an entity by the World Health Organization (WHO) definition (2010), and its pathogenesis has not been known adequately because of the rarity. Here, we report a case of a 22-year-old female who had been followed up for a cystic lesion at the tail of the pancreas pointed out by a screening computed tomography (CT) scan 7 years ago. The tumor grew in size from 3.3 to 5.1 cm in diameter for 6 years (0.3 cm per year). Particularly, it rapidly grew up to 6.3 cm in the latest 3 months in concurrence with the emergence of epigastralgia. A contrasted CT scan revealed the irregularly formed, multilocular cystic tumor having thin septum and calcification. The intratumoral magnetic resonance imaging intensity in the T1 and T2 weighted images were low and high, respectively. No communications between the tumor and the main pancreatic duct (MPD) were found, but the tumor displaced the MPD. She underwent surgical resection because the tumor was growing, turned symptomatic, and it seemed difficult to be diagnosed correctly until totally biopsied. Spleen-preserved distal pancreatectomy was performed. It was pathologically diagnosed as ACA; the cyst was lined by cells with normal acinar differentiation; cuboidal cells with round, basally oriented nuclei and eosinophilic granules in its apical cytoplasm. The abdominal pain has disappeared, and no recurrences have been found during a 5-year follow-up. Clinicians are recommended to consider an ACA as one of differential diagnoses of cystic tumors of the pancreas to provide appropriate diagnostics and therapeutics.

Unicystic granulosa cell tumor.

Granulosa cell tumors are the most frequent sex cord stromal tumor and account for approximately 5% of all primary ovarian tumors. About 5% occur before puberty and 40% occur in the menopausal age group; however, these tumors have an indolent biological behavior [1]. The clinical presentation in most cases is due to estradiol secretion but some may be nonfunctional or may present with virilizing symptoms. Unilocular and multilocular cystic granulosa cell tumors have been reported in the literature but are rare disease processes [2,3].

First adult case of sporadic localized glomerulocystic kidney mimicking a tumor

Glomerulocystic kidneys (GCKs) are mainly observed in infants and young children, and are characterized by the cystic dilatation of Bowman's space to form glomerular cysts (GCs). GCKs are associated with various conditions. Additionally, the cystogenesis of GCKs remains controversial. The present study describes a rare adult case of a sporadic localized GCK that radiologically mimicked a multilocular cystic tumor, and analyses the features of GC. A 42-year-old male with hematuria underwent a right partial nephrectomy for a cystic mass. The majority of the cyst was distributed in the cortex and contained a single collapsed glomerulus. Using serial sections, narrow and serpiginous proximal tubules that continued to the GCs were detected. These findings suggested that obliteration at the glomerulotubular junction was not the primary cause of GC in this case. To the best of our knowledge, this is the first adult case of a sporadic localized GCK mimicking a tumor. Unnecessary surgical procedures may be avoided by careful evaluation of computed tomography scans and magnetic resonance imaging, although localized GCKs are quite rare.

Pediatric Multilocular Cystic Nephroma Extending into the Renal Pelvis and Ureter

OZET Multilocular cystic nephroma (MCN) is a rare tumor at the most benign end of the spectrum of the multilocular cystic neplasms of kidney. Nephrectomy is curative for MCN. In this case-report, we present a 16-month-old girl with a 10x15 cm multilocular cystic renal tumor extending into the renal pelvis and proximal ureter on the right side demonstrated on magnetic resonance imaging. Nephrectomy was performed. The pathology was completely consistent with MCN.

Interesting cases in gynecologic pathology: case 5

An 8.5-year-old girl presented with breast development, irregular uterine bleeding, and a spurt in height during the previous 9 months. She also complained of rapid increase of abdominal girth and body weight (4 kg). No remarkable past history or family history was noted. Her height (143 cm), breast development (Tanner stage 3), and pubic hair (Tanner stage 2) were compatible with precocious puberty. Laboratory examinations showed microcytic hypochromic anemia (Hb 9.2g/dL), and serum estradiol was 138pg/mL. LH and FSH were in the undetectable level even after a LH-RH (100 μg) injection. Ovarian tumor markers including CEA, CA19-9, CA125, α-fetoprotein, and hCG were within the normal range. Magnetic resonance imaging revealed a giant multilocular cystic tumor (25 × 14 × 10 cm) in the lower abdomen. Tumor resection was performed. The tumor originated from the right ovary and contained 3500 × mL of yellowish serous fluid. The left ovary was grossly normal. The resected right ovarian tumor was multilocular cystic, measuring 16.0 × cm in the greatest dimension, with occasional foci of whitish yellow elevated components in the cystic wall.

Segment I intrahepatic biliary cystadenocarcinoma impinging on the hepatic vein

Biliary cystadenoma is a rare cystic tumor; prognosis is dependent on the completeness of the surgical resection. The case of a 65-year-old woman with a multilocular cystic hepatic tumor is reported. Radiological and laboratory findings suggested the diagnosis of cystadenoma with localized malignant degeneration. A surgical resection of hepatic Segment I was performed, requiring total vascular exclusion (TVE) of the liver and a needle aspiration of a non-degenerated cyst to permit total resection. TVE and decompression of a cyst presumed to be benign may be warranted to achieve a safe and complete resection of biliary cystadenoma.

Fronto-parietal osteoblastoma with secondary aneurysmal bone cyst: A case report

Osteoblastomas and aneurysmal bone cysts each comprise 1% of primary bone tumours. As both osteoblastomas and aneurysmal bone cysts are not common, osteoblastomas with secondary aneurysmal bone cysts of calvaria are extremely rare. Only three cases describing a secondary aneurysmal bone cyst in the setting of a calvarial osteoblastoma can be found in the literature. We report the case of the surgical resection of the fronto-parietal osteoblastoma accompanying a secondary aneurysmal bone cyst. The case is a 24-year-old male with a 2-year history of a painless lump in the hair-bearing region of the left fronto-parietal area without neurologic symptoms. Computed tomography showed an intradiploic tumour with maintained inner and outer cortex of the left front-parietal bones. 3.0-T magnetic resonance imaging showed a well-circumscribed, intradiploic, multilocular cystic tumour. A gadolinium-enhanced sequence showed strong peripheral and septal enhancement. These findings were consistent with an osteoblastoma associated with secondary aneurysmal bone cyst. An en bloc tumour resection with a 10-mm horizontal margin was completed without complications. The calvarial defect was covered by calvarial bone graft harvested from the contralateral fronto-parietal bone. The postoperative course was uneventful. Pathological diagnosis was consistent with the osteoblastoma with secondary aneurysmal bone cyst. After a follow-up period of 2 years, there was no evidence of recurrence. The combination of osteoblastoma and aneurysmal bone cyst of the calvaria is a rare clinical entity. Careful preoperative examination and complete resection of the tumour are essential.

A one-stage operation for abdominal aortic aneurysm and intraductal papillary mucinous neoplasms of the pancreas: report of a case

Pancreatic surgery concomitant with abdominal aortic repair is rarely chosen due to concerns about prosthetic infection following pancreatic leakage and the poor prognosis of pancreatic neoplasms. We herein report a successfully treated case of infrarenal abdominal aortic aneurysm and intraductal papillary mucinous neoplasms of the pancreas treated by a one-stage operation. A 75-year-old male with a history of cerebral infarction and chronic subdural hematoma was referred to our department with a pulsatile abdominal mass. A 70-mm infrarenal abdominal aortic aneurysm with severe proximal neck angulation and a 28-mm multilocular cystic tumor with mural nodules in the pancreas body were detected. Abdominal aortic repair with a prosthetic graft and distal pancreatectomy were performed simultaneously. The postoperative course was mostly uneventful, and he was discharged to a rehabilitation facility.

Abstract 3640: Potential cooperation of monoclonal antibody based targeting of gamma-glutamyl transferase (GGT1) with chemotherapy in kidney tumor xenografts

Abstract Gamma-glutamyl transferase (GGT1) is a cell membrane bound enzyme that functions in gamma-glutamyl cycling, to provide cells with intracellular glutathione (GSH). GGT1 has been recognized to participate in chemotherapeutic resistance of tumors to carboplatin and various alkylating agents by increasing GSH levels intracellularly, thus allowing the tumor to escape electrophilic damage. Cysteinylglycine generated by membrane bound GGT1 can bind to extracellular cisplatin and prevent it from entering the cell. Mechanisms that target GGT1 and alter its function have been postulated to increase tumor sensitivity to conventional chemotherapies. We have generated a novel monoclonal antibody (mAb), 8G9 [IgG2a, k1] that recognizes GGT1. An immunohistochemical (IHC) survey of benign adult human tissues revealed an antigen distribution in formalin-fixed, paraffin embedded tissues consistent with previous reports of GGT1 expression. A subsequent IHC screen of nearly 100 kidney tumors revealed that scoring based on 8G9 immunoreactivity showed a preference for clear cell (94.45%), multilocular cystic (100%) and papillary cell (95.83%) kidney tumors. A statistical association of 8G9 immunostaining with Fuhrman nuclear grade or pathology staging was not evident. FACS analysis confirmed that 8G9 recognizes a cell surface epitope. Cross-immunoprecipitations performed with 8G9 and a commercially available GGT1 antibody confirmed that 8G9 recognizes GGT1. 8G9 exhibited a unique preference for native GGT1 likely through recognition of a combined epitope formed by the association of the GGT1 heavy and light chains. Because 8G9 appears to recognize a native, surface accessible GGT1 epitope, we performed xenograft studies to test the efficacy of 8G9 in blocking kidney tumor growth either as a single agent or in combination with cisplatin or carboplatin. Athymic nude mice were engrafted with the human kidney tumor cell line Caki-1. Upon successful tumor engraftment, mice were treated with 8G9, cisplatin or carboplatin as single agents or with 8G9+ ciplatin or 8G9 + carboplatin. As a single agent, 8G9 treatment did not result in a reduction of relative tumor volume. Likewise, there was little difference in relative tumor volume in mice treated a combination of 8G9 and carboplatin. However, 8G9 + cisplatin treatment exhibited a modest reduction in tumor volume. These preliminary data suggest that targeting GGT1 may have a cooperative effect in reducing tumor growth in the presence of cisplatin, and that the efficacy of chemotherapy combined with targeting GGT1 may be particularly sensitive to the mechanistic action of the chemotherapeutic agent. Further studies are needed to fully evaluate GGT1 as a potential drug target. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3640. doi:10.1158/1538-7445.AM2011-3640

Mixed Epithelial and Stromal Tumor of the Kidney With Elevated Serum Level of Cancer Antigen 125

Mixed epithelial and stromal tumor of the kidney is a newly categorized lesion, with few reported cases. We report a rare case of a 45-year-old woman with a palpable abdominal mass and elevated serum level of serum cancer antigen 125, who was not receiving hormones or contraceptive agents. Abdominal magnetic resonance imaging revealed a large multilocular cystic tumor that arose in the left central kidney. Nephrectomy was performed under the initial impression of cystic renal cell carcinoma; however, a diagnosis of mixed epithelial and stromal tumor was confirmed according to pathological and immunohistochemical findings. Serum level of cancer antigen 125 returned to normal after 1 month postoperatively and no recurrence was found in the following 18 months.

Huge Mediastinal Cystic Tumor Penetrating the Sternum

We report a very rare case of a huge anterior mediastinal tumor penetrating the sternum that was diagnosed in a 59-year-old woman. The tumor was completely resected en bloc with the manubrium sterni, and the chest wall defect was closed with a pectoralis major muscle flap. Histologic examination of the cystic mass revealed the diagnosis of a benign mediastinal cystic tumor, most likely a benign cystic mature teratoma.

A case report of undifferentiated carcinoma with osteoclast-like giant cells of the pancreas and literature review.

Osteoclast-like giant cell tumors rarely arise in the pancreas. Here we report the case of a 78-year-old woman who was diagnosed with a well-defined 3 cm multilocular mass in the pancreatic body by the use of ultrasonography, computed tomography and magnetic resonance imaging. The rim and the septa of the tumor were well enhanced. The distal pancreas was removed with the spleen and the peripancreatic lymph nodes. Macroscopically, the mass was composed predominantly of a multilocular cystic tumor filled with hemorrhagic necrosis, and partly composed of solid components. A histopathological study showed a proliferation of multinucleated osteoclast-like giant cells and spindle cells. Although the predominant tumor cells were strongly positive for vimentin and CD68 and negative for epithelial markers, there were some sparsely scattered cytokeratin-positive neoplastic glands. Seventeen months after surgery, the patient is still alive and has had no recurrence. Below we review 32 cases of osteoclast-like giant cell tumor of the pancreas that have been reported in English literature since 2000.

Primary Ovarian Mucinous Cystic Tumor With Prominent Theca Cell Proliferation and Focal Granulosa Cell Tumor in its Stroma: Case Report, Literature Review, and Comparison With Sertoli-Leydig Cell Tumor With Heterologous Elements

A 73-year-old woman was found to have a 22 cm unilateral multilocular mucinous cystic tumor of the ovary. Microscopic examination showed a routine appearance of the epithelial component, which ranged from benign to borderline to low-grade carcinoma. The stromal component was unusual because of a striking cellular theca cell component in the stroma, which, in turn, merged with a component of adult granulosa cell tumor. The "parent" neoplasm in this case and 3 other similar cases in the literature appears to be the mucinous neoplasm, in contrast with the other example of mucinous neoplasia associated with sex cord neoplasia, the Sertoli-Leydig cell tumor with heterologous elements, in which the "parent" neoplasm is likely the Sertoli-Leydig cell tumor.

Mucinous cystic neoplasm of the pancreas presenting with hemosuccus pancreaticus: Report of a case

Hemosuccus pancreaticus (HP) is mostly induced by a ruptured pseudoaneurysm or hemorrhage from a pseudocyst in chronic pancreatitis. We herein report a rare case with HP induced by tumor hemorrhage. The present patient is a 71-year-old woman referred to us with a diagnosis of severe progressive anemia. Endoscopy revealed hemorrhage from the papilla of Vater. Computed tomography showed a multilocular cystic tumor in the tail of the pancreas. The patient underwent a distal pancreatectomy. The histopathological diagnosis was carcinoma in mucinous cystadenoma. No cancer infiltration into the pancreatic duct was detected. Pancreatography of the resected specimen demonstrated an overt communication between the main pancreatic duct and the cystic cavity of the tumor, which was not demonstrated preoperatively by endoscopic retrograde pancreatography. Although the cause of HP is mainly acute or chronic pancreatitis, we should bear in mind that a pancreatic tumor may be a possible cause of HP and that, as such, prompt and proper treatment is mandatory.

Cystadenoma Originating From the Gallbladder

Biliary cystadenomas are very uncommon benign tumors. They are very rare occurrences in the gallbladder, and there are only a few case reports in the literature. 1-3 Cystadenomas are more frequently seen among middle-aged women. The clinical presentation varies and depends on the size and location of the cyst. They are unilocular or multilocular cystic tumors that contain septations. Although biliary cystadenomas are of a benign nature, they may recur after excision, and there is a risk of development of cystadenosarcomas. 4-6 Hepatobiliary cystadenomas are most commonly seen in the liver (83%) followed by the extrahepatic biliary system (13%) and gallbladder (0.02%). 7 In this report, we present the sonographic results of a rare case of cystadenoma originating in the gallbladder.

Multi-detector CT Features of Benign Adnexal Lesions

The purpose of our study was to evaluate the multidetector computed tomography (MDCT) features of benign adnexal lesions. We report the MDCT features of 68 histologically proven benign adnexal lesions. Pathologic diagnoses were nonneoplastic adnexal cysts (n = 16), endometriomas (n = 12), serous or mucinous cystadenomas (n = 15), fibromas or fibrothecomas (n = 7), teratomas (n = 6), and a variety of benign adnexal lesions (n = 12). The CT protocol included scanning of the abdomen after the intravenous administration of iodinated contrast material (portal phase) using a detector collimation of 16 x 0.75 mm and a pitch of 1.2. Ovarian cysts had a characteristic CT appearance of a cystic lesion, with smooth, thin wall, and occasionally a few septa. Serous and mucinous cystadenomas were detected as multilocular cystic tumors containing serous fluid or liquids of higher than water CT density, respectively. Dilated fallopian tube was seen as an oblong, tubular, fluid-filled structure. MDCT was accurate to characterize mature cystic teratomas. Endometriomas had a variable CT appearance, including a unilocular or multilocular cystic mass, and a homogeneous hyperdense mass lesion. Fibrous tissue had a 50 HU CT density in patients with fibromas or fibrothecomas. MDCT may provide accurate diagnostic information about the benign nature of adnexal lesions.

Multilocular cystic renal cell carcinoma: a case report and literature review

Objective To discuss the diagnosis and outcome of multilocular cystic renal cell car-cinoma. Methods The clinic data of 1 case of multilocular cystic renal cell carcinoma were reviewed with its clinical manifestation, imaging, pathology and therapy in our hospital. The male patient aged 49 was incidentally found to have a right renal tumor. The CT scan showed a multiloeular cystic tumor in the low pole of the right kidney with a clear outline. The thin septa were found in the tumor, which were enhanced in the enhancement CT scan. The enhancement MRI showed the cystic wall was en-hanced. Results The patient received a partial nephrectomy as his treatment. The pathological char-acteristics were as following: the multilocular cystic tumor was about 3 cm×2 cm×2 cm with clear serosity in it. The cystic wall was smooth with the width of 0.1-0.2 cm. Most of the cystic cavities were covered by monostratified or stratified cubic clear cells, and some were covered by squamous epi-thelium or no epithelium at all. The septum was composed of collagen fiber, and clear cells were found in it. The clear cells form small collections but do not form expansile nodules. The final pathological diagnosis was multilocular cystic renal cell carcinoma. The follow-up was 20 months, without local re-currence or distant metastasis was found. Conclusions Multilocular cystic renal cell carcinoma (MCRCC) is a rare variant of renal cell carcinoma with a good prognosis. MCRCC is an uncommon tumor of the kidney composed of multiple cysts with clear cells in the septa indistinguishable from grade I renal cell carcinoma. Most patients are asymptomatie and the tumors are discovered inciden-tally. The preoperative diagnosis of MCRCC immediately depends on imaging studies. Pathology is the key to diagnosis. Key words: Multilocular cystic renal cell carcinoma; Clinical research