A Comprehensive Commentary on the Multilocular Cystic Renal Neoplasm of Low Malignant Potential: A Urologist’s Perspective

[Clinicopathological characteristics and prognosis of multilocular cystic renal neoplasm of low malignant potential]

OBJECTIVE

To analyze the clinicopathological characteristics and prognosis of patients with multilocular cystic renal neoplasm of low malignant potential and compare the clinicopathological characteristics of patients with multilocular cystic renal neoplasm of low malignant potential who underwent different surgical methods.

METHODS

Clinicopathological data and prognosis of patients admitted to Peking University Third Hospital from January 2010 to September 2023 were collected. Patients who underwent radical nephrectomy or nephron-sparing surgery and were pathologically diagnosed with multilocular cystic renal neoplasm of low malignant potential were identified. Based on the surgical methods, the patients were divided into radical nephrectomy group and nephron-sparing surgery group. The clinicopathological characteristics of the two groups were compared.

RESULTS

A total of 35 patients were enrolled in this study. The median age at diagnosis was 53.0 (39.0-62.0) years. Among the 35 patients, 23 were males (65.7%) and 12 were females (34.3%). Nine patients underwent radical nephrectomy (25.7%), while 26 patients underwent nephron-sparing surgery (74.3%). The clinical T-stage of 35 patients did not exceed T2a stage. The median operation time was 145.0 min, and the median estimated intraoperative blood loss was 20.0 mL. The median postoperative hospitalization days was 6.0 d. The postoperative pathological results did not indicate renal sinus invasion, sarcomatous change, adrenal invasion or lymph node invasion. Based on the surgical methods, the patients were divided into a radical nephrectomy group and a nephron-sparing surgery group. There was no significant difference in clinicopathological charac-teristics between the two groups. Except for one patient who was lost to the follow-up, all the other patients were followed up for 8-111 months, with a median follow-up time of 70.5 months. Only one patient died from non-cancer-specific reasons, other patients had no tumor metastasis or recurrence.

CONCLUSION

Patients with multilocular cystic renal neoplasm of low malignant potential have a good prognosis. There is no significant difference in clinicopathological characteristics of patients between nephron-sparing surgery group and radical nephrectomy group for multilocular cystic renal neoplasm of low malignant potential.

Clinicopathological characteristics and typing of multilocular cystic renal neoplasm of low malignant potential

BACKGROUND

Up until now, no research has been reported on the association between the clinical growth rate of multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) and computed tomography (CT) imaging characteristics. Our study sought to examine the correlation between them, with the objective of distinguishing unique features of MCRNLMP from renal cysts and exploring effective management strategies.

AIM

To investigate optimal management strategies of MCRNLMP.

METHODS

We retrospectively collected and analyzed data from 1520 patients, comprising 1444 with renal cysts and 76 with MCRNLMP, who underwent renal cyst decompression, radical nephrectomy, or nephron-sparing surgery for renal cystic disease between January 2013 and December 2021 at our institution. Detection of MCRNLMP utilized the Bosniak classification for imaging and the 2016 World Health Organization criteria for clinical pathology.

RESULTS

Our meticulous exploration has revealed compelling findings on the occurrence of MCRNLMP. Precisely, it comprises 1.48% of all cases involving simple renal cysts, 5.26% of those with complex renal cysts, and a noteworthy 12.11% of renal tumors coexisting with renal cysts, indicating a statistically significant difference (P = 0.001). Moreover, MCRNLMP constituted a significant 22.37% of the patient population whose cysts demonstrated a rapid growth rate of ≥ 2.0 cm/year, whereas it only represented 0.66% among those with a growth rate below 2.0 cm/year. Of the 76 MCRNLMP cases studied, none of the nine patients who underwent subsequent nephron-sparing surgery or radical nephrectomy following renal cyst decompression experienced recurrence or metastasis. In the remaining 67 patients, who were actively monitored over a 3-year postoperative period, only one showed suspicious recurrence on CT scans.

CONCLUSION

MCRNLMP can be tentatively identified and categorized into three types based on CT scanning and growth rate indicators. In treating MCRNLMP, partial nephrectomy is preferred, while radical nephrectomy should be minimized. After surgery, active monitoring is advisable to prevent unnecessary nephrectomy.

Immunohistochemical expression of cytochrome P4A11 (CYP4A11), carbonic anhydrase 9 (CAIX) and Ki67 in renal cell carcinoma; diagnostic relevance and relations to clinicopathological parameters

BACKGROUND

Cytochrome P4A11 (CYP4A11) is a member of cytochrome p450 family, which is involved in arachidonic acid metabolism that participates in promoting malignant cell proliferation, progression, and angiogenetic capacity. Carbonic Anhydrase 9 (CAIX) is a transmembrane protein that plays an integral part in regulating hypoxia which affects cancer cell metabolism, proliferation and promotes metastasis. The aim of this study was to evaluate the immunohistochemical expression of CYP4A11, CAIX and ki67 in RCC subtypes in relation to clinicopathological parameters and to evaluate the diagnostic significance of CYP4A11 and CAIX in differentiating renal cell carcinoma (RCC) subtypes.

MATERIALS AND METHODS

one hundred primary RCC cases, collected from Pathology Department, Faculty of Medicine, Tanta University and from private laboratories, were evaluated for immunohistochemical expression of CYP4A11, CAIX and ki67.

RESULTS

CYP4A11 was expressed in 59% of RCC; with 91.7% sensitivity and 90% specificity in differentiating clear cell and non-clear cell subtypes. CAIX was expressed in 50% of RCC; with 95% sensitivity, 80% specificity. High expression of CYP4A11 was statistically positively associated with higher tumor grade, high expression of CAIX was statistically positively associated with lower tumor grade and absence of necrosis and high ki67 labeling index was significantly associated with clear cell subtype, larger tumor sizes, higher tumor grade, advanced tumor stage, fat invasion and vascular invasion.

CONCLUSIONS

CYP4A11 and CAIX can be used as diagnostic markers to differentiate clear cell RCC from other subtypes. CYP4A11 is more diagnostically accurate and specific than CAIX. High expression of CYP4A11, low CAIX expression and high ki67 labeling index were related to features of aggressive tumor behavior.

Multicystic Clear Cell Renal Tumors With Low-grade Nuclear Features: Time to Include TFE3 Translocation-associated Carcinomas

TFE3 -rearranged renal cell carcinoma (RCC) is a distinct, uncommon entity with more than 20 different fusion partners identified; however, histomorphology may be suggestive of specific fusion partners in select TFE3 -rearranged RCCs. For example, most MED15 :: TFE3 fusion associated RCCs exhibit multilocular cystic morphology, mimicking multilocular cystic renal neoplasm of low malignant potential. Here we present a case of MED15 :: TFE3 RCC in an older adult and review the literature with an emphasis on practical diagnostic approaches for predominantly cystic, low-grade, clear cell renal tumors.

Mixed epithelial and stromal tumor of the kidney: A retrospective clinicopathological evaluation

OBJECTIVE

Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare renal tumor for which there is limited clinical case experience. The aim of this study was to investigate the clinicopathological features, imaging manifestations, immunohistochemical phenotype, diagnosis, and differential diagnosis of MESTK.

METHODS

We systematically evaluated the clinicopathological characteristics of 13 patients diagnosed with MESTK from 2016 to 2022.

RESULTS

There were 12 female cases and 1 male case, and their age ranged from 24 to 62 (mean age 47 years). The tumor was located in the left kidney in 11 patients. Seven of these patients were located in the upper pole of the left kidney. The mean diameter of the tumor was 4.6 cm (range 1.3-8.6 cm), and the main body of the tumor was mainly located in the medulla or medulla. In 7 cases, the tumors were clearly outlined, 4 cases had clear but irregular borders, and in 3 cases, the masses broke through the renal capsule but did not invade the surrounding organs. All tumors had varying proportions of cystic and solid components. In most tumors, the epithelial cell component was predominant. Among the epithelial components, we observed a predominance of large cysts. Small cysts and tubular structures were also seen; the least common were papillary structures. The most common types of lining epithelium were flat and cuboidal. The cell cytoplasm was predominantly eosinophilic with hyaline degeneration. The tumor cells were composed of different proportions of sparse hypocellular areas and dense hypercellular areas between these cells. In most cases, the cellular stroma had an ovarian-like appearance. It is characterized histologically by mature adipocytes, thick-walled blood vessels, and chronic inflammatory cells. Calcification and collagenization were seen in a few cases. In all female patients, estrogen and progesterone receptors in the interstitial component were almost always positively expressed. In male patients, all interstitial components showed locally positive expression of androgens.

CONCLUSION

MESTK had unique characteristics with complex and variable lesion shapes. There was a high degree of overlap with cystic kidney cancer, and the rate of missed and misdiagnosis was extremely high. The diagnosis could not be confirmed by preoperative imaging. The final diagnosis depended on pathomorphology.