Renal epithelioid angiomyolipoma with a negative premelanosome marker immunoprofile: a case report and review of the literature

Comprehensive Insights Into Renal Perivascular Epithelioid Cell Neoplasms: From Molecular Mechanisms to Clinical Practice

Perivascular epithelioid cell neoplasms (PEComas) are a rare category of mesenchymal tissue tumors, manifesting across various tissues and organs such as the kidneys, liver, lungs, pancreas, uterus, ovaries, and gastrointestinal tract. They predominantly affect females more than males. PEComas characteristically express both melanocytic and smooth muscle markers, making immunohistochemistry vital for their diagnosis. Renal angiomyolipoma (AML) represents a common variant of PEComas, typically marked by favorable prognoses. Nonetheless, only a small fraction of subtypes, especially epithelioid AML, possess the capacity to be malignant. Renal PEComas usually appear as asymptomatic masses accompanied by vague imaging characteristics. The main methods for diagnosis are histopathological analysis and the application of immunohistochemical stains. Presently, a uniform treatment plan for renal PEComas is absent. Strategies for management include active surveillance, selective arterial embolization, surgical procedures, and drug-based treatments. The focus of this review is on renal PEComas, shedding light on their pathogenesis, pathological characteristics, clinical presentations, diagnosis, and treatment modalities, and incorporating a clinical case study.

Sonazoid-enhanced ultrasonography and pathologic characters of CD68 positive cell in primary hepatic perivascular epithelioid cell tumors: A case report and literature review

Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor rarely described in the liver. Sonazoid is a new ultrasound contrast with both vascular and post-vascular phases due to the uptake of Kupffer cell. CD68 is a defined immunohistorical staining marker for macrophage including Kupffer cell. No previous cases have been reported to reveal Kupffer images in the post-vascular phase by using Sonazoid and pathologic characters of CD68 positive cell in PEComa. Herein, we describe the first case to present Sonazoid contrast-enhanced ultrasonography (CEUS) findings in Kupffer images and CD68 positive cell in hepatic PEComa which may lead to rethink of the phagocytic properties of macrophages.

Can renalase be a novel candidate biomarker for distinguishing renal tumors?

Renalase (RNLS) is synthesized mainly in renal tissues. The function of RNLS in cancerous renal tissues has not been investigated. We investigated the synthesis of RNLS in chromophobe renal cell carcinoma, papillary renal cell carcinoma and clear cell renal cell carcinoma with Fuhrman grades (FG): FG1, nucleoli are absent or inconspicuous and basophilic; FG2, nucleoli are conspicuous and eosinophilic and visible but not prominent; FG3, nucleoli are conspicuous and eosinophilic; FG4, extreme nuclear pleomorphism, multinucleate giant cells, and/or rhabdoid and/or sarcomatoid differentiation. We used 90 tissue samples including 15 healthy controls, 15 chromophobe renal cell carcinoma tissues and 10 papillary renal cell carcinoma renal tissues: 12 FG1, 14 FG 2, 14 FG 3 and 10 FG4. RNLS in the tissue samples was measured using enzyme linked immunosorbent assay and immunostaining of RNLS in these tissues. RNLS was significantly greater in the chromophobe renal cell carcinoma and papillary renal cell carcinoma tissues than the control. The least amount of RNLS was found in the renal tissues of clear cell renal cell carcinoma FG1; the amount of RNLS increased as the FG grades increased. Because RNLS increased significantly in renal tissues due to cancer, except for clear cell renal cell carcinoma FG1, RNLS may be useful biomarker for distinguishing grades of renal cancer. Because RNLS increases cell survival, anti-RNLS preparations may be useful for treating cancer in the future.

Epithelioid angiomyolipoma with tumor thrombus in IVC and right atrium

Epithelioid angiomyolipoma is an uncommon subtype of renal angiomyolipoma associated with potentially malignant behavior and is considered a distinct entity by the World Health Organization classification of renal tumors. We present a case of an epithelioid variant of angiomyolipoma with extension into the renal vein, inferior vena cava reaching up to the right atrium. Pre-operatively, a diagnosis of renal cell carcinoma was considered based on imaging findings. Intra-operatively due to extensive adhesions, surgical resection was not performed and only tissue sampling was performed for histopathology. Microscopic examination revealed short fascicles of spindle cells and perivascular epithelioid cells. A differential diagnosis of renal cell carcinoma with sarcomatoid differentiation was considered. The immunohistochemical profile showed tumor cells that express Melan-A and smooth muscle actin, while they were negative for pan-cytokeratin, PAX8, CK7, CD117 and CD34. Therefore a diagnosis of epithelioid angiomyolipoma was rendered. The presence of intravascular thrombi on radiological investigation and carcinoma-like growth pattern on light microscopy may compound an erroneous diagnosis of renal cell carcinoma. Hence, it is prudent for the urologist to consider differential diagnosis other than renal cell carcinoma when confronted with a renal neoplasm presenting with intravascular thrombi. In these cases, a core biopsy should be planned pre-operatively and diagnosis should be made with aid of appropriate immunohistochemical markers.

Metastatic epithelioid angiomyolipoma treated with everolimus in a patient receiving hemodialysis: A case report

Introduction

A patient undergoing hemodialysis and being treated with everolimus for metastatic epithelioid angiomyolipoma has never been described in the literature, to our knowledge.

Case presentation

A 53‐year‐old woman who had undergone trans‐arterial embolization for epithelioid angiomyolipoma was referred with a chief complaint about right knee pain. Hemodialysis had been started after the embolization. Needle biopsy specimens of tumors obtained from behind the right kidney and in the right femur were diagnosed as epithelioid angiomyolipoma metastases. The patient underwent treatment with everolimus and achieved a partial response after 6 months of treatment without serious adverse events.

Conclusion

Everolimus might be effective for patients with metastatic epithelioid angiomyolipoma who are undergoing hemodialysis.

Eosinophilic Kidney Tumors: Old and New

Context.—

Eosinophilic cytoplasm is the most common finding of difficult-to-classify kidney tumors. Morphology, cytogenetics, and immunohistochemical stains are discriminatory. This review compares well-recognized tumors such as granular clear cell carcinoma, papillary variants, chromophobe renal cell carcinoma, and oncocytoma and introduces newly described entities of hybrid oncocytic tumors, carcinomas defined by translocations, and carcinomas with deficiencies in the tricarboxylic acid cycle. The focus is on immunostaining, clinical correlations, and differential diagnoses. Representative examples of some entities are presented with elaboration on their workup.

Objective.—

To provide a review of the differential diagnoses for renal neoplasms with eosinophilic cytoplasm and elaborate on methods that may assist with correct identification.

Data Sources.—

Review of current literature on kidney tumors with eosinophilic cytoplasm, as well as the authors' personal experience.

Conclusions.—

Eosinophilic cytoplasm is a feature shared by many kidney tumors. Understanding the morphologic differences and the role of ancillary studies is key when encountering such a tumor.

Gastric Angiomyolipoma Masquerading as Gastric Malignancy

Gastric angiomyolipoma (AML) is extremely rare, with only 3 cases reported in English literature, all of which presented with upper gastrointestinal bleed, either in the form of hematemesis or melena. A 42-year-old man presented with upper gastrointestinal bleed, the source of which was found to be a large mass in the stomach, which was shown histologically to be gastric AML. This is the fourth but largest tumor (9 × 6 × 5 cm) to be reported to date.

Hepatic Angiomyolipoma Staining in the Post-vascular Phase of Contrast-enhanced Ultrasound Due to the Presence of Macrophages

A 47-year-old Japanese man was referred to hospital after the detection of a liver tumor. Dynamic computed tomography and gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging were consistent with a diagnosis of hepatocellular carcinoma (HCC). No perfusion defect was observed in the post-vascular phase of contrast-enhanced ultrasound (CEUS). Histopathological staining of the tumor cells was positive for antibodies against HMB-45 and cluster of differentiation (CD) 68, confirming the diagnosis of hepatic angiomyolipoma (HAML). These findings indicated the presence of macrophages in HAML. We herein report a case of HAML explain how macrophages that are present within the tumor affect the staining characteristics in the post-vascular phase of CEUS.

CT-imaging features of renal epithelioid angiomyolipoma

Background

The aim of this study was to describe the computed tomography (CT)-imaging features of renal epithelioid angiomyolipomas (E-AMLs) to understand and recognize this new category of renal tumors.

Methods

Institutional review board approval was obtained for this retrospective study. Clinical data and preoperative CT images of 11 cases of E-AML were retrospectively analyzed. All patients had unenhanced and tri-phase dynamic enhanced CT examination. CT-imaging features including tumor size, existence of fat and calcification, enhancement degree, enhancement pattern, and enhancement heterogeneity were evaluated.

Results

The patients were ten women and one man. The size of tumor ranged from 1.8 to 10.3 cm. All of them had distinct edges; one had a lobulated appearance, ten had bulging contour of the involved kidney, and four lesions had intratumoral fat. Eight of the E-AMLs demonstrated hyper-attenuation, two as iso-attenuation, and one as hypo-attenuation compared with renal parenchyma on unenhanced CT images. Contrast-enhanced CT features were markedly heterogeneous in eight cases (73 %). The predominant enhancement pattern was rapid wash-in to slow wash-out (91 %).

Conclusions

The radiological appearance of most E-AMLs has a tendency to be hyper-attenuated on precontrast CT with or without fat component and demonstrates a rapid wash-in to slow wash-out dynamic enhancement pattern.

Development of pathological diagnostics of human kidney cancer by multiple staining using new fluorescent Fluolid dyes

New fluorescent Fluolid dyes have advantages over others such as stability against heat, dryness, and excess light. Here, we performed simultaneous immunostaining of renal tumors, clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, acquired cystic disease-associated RCC (ACD-RCC), and renal angiomyolipoma (AML), with primary antibodies against Kank1, cytokeratin 7 (CK7), and CD10, which were detected with secondary antibodies labeled with Fluolid-Orange, Fluolid-Green, and Alexa Fluor 647, respectively. Kank1 was stained in normal renal tubules, papillary RCC, and ACD-RCC, and weakly or negatively in all other tumors. CK7 was positive in normal renal tubules, papillary RCC, and ACD-RCC. In contrast, CD10 was expressed in renal tubules and clear cell RCC, papillary RCC, AML, and AC-RCC, and weakly in chromophobe RCC. These results may contribute to differentiating renal tumors and subtypes of RCCs. We also examined the stability of fluorescence and found that fluorescent images of Fluolid dyes were identical between a tissue section and the same section after it was stored for almost three years at room temperature. This indicates that tissue sections can be stored at room temperature for a relatively long time after they are stained with multiple fluorescent markers, which could open a door for pathological diagnostics.