Malignant oncocytoma of the maxillary sinus--an ultrastructural study

A unique case of a malignant oncocytoma of the maxillary sinus is reviewed in detail. The ultrastructural findings are presented. The histologic and ultrastructural criteria that characterize oncocytes and the clinicopathologic features of benign and malignant oncocytomas are discussed. This case represents the eleventh reported case that would truly qualify as a malignant oncocytoma of the paranasal sinuses.     

Preoperative diagnosis of renal oncocytoma and treatment possibilities

We report 2 cases of renal oncocytoma and review the literature. A number of radiological, cytological and ultrastructural differential features of oncocytoma that are known today make preoperative diagnosis of this tumour possible. Analysis of the reported cases allows to conclude that oncocytomas are of universally benign character with a very good prognosis. Metastases have not been documented. Thus we suggest that many patients with oncocytoma could be spared the operation of nephrectomy. Partial kidney resection or heminephrectomy are to be preferred with solitary oncocytomas of a moderate size.     

Chromophobe cell carcinoma: analysis of five cases

Five cases of a recently characterized renal neoplasm, chromophobe cell carcinoma, encountered during an ultrastructural and DNA flow cytometric study of renal cortical neoplasms are described. These tumors usually are dark on gross examination and often are associated with focal hemorrhage or necrosis. Microscopically the tumor cell cytoplasm ranges from clear to eosinophilic, potentially eliciting a broad differential diagnosis encompassing renal cell carcinoma and oncocytoma. Ultrastructural studies disclosed the diagnostically required numerous complex cytoplasmic vesicles of unknown composition and origin, and DNA ploidy studies revealed an aneuploid cell population in three of five cases, which correlates with the malignant potential.     

Renal oncocytoma—bilateral,multifocal

One hundred thirteen cases of “grade I renal oncocytoma” are reported from several centers. All centers report absence of associated metastatic disease. In the present review of 219 radical nephrectomy specimens, 11 renal oncocytomas were identified, an incidence of 5 per cent. No diagnostic angiographic features could be identified. Multifocal potential is exemplified by study of a bilateral case and 2 cases of 2 independent oncocytomas in the same kidney. The fine histologic criteria distinguishing oncocytoma from malignant renal tumors suggest that the oncocytomas may have the potential of malignant degeneration. The possible “premalignant classification” of oncocytomas and the lack of dependable diagnostic features radiographically force the management to be the same as for Stage I renal carcinoma. The prognostic information available after histologic definition of renal oncocytoma is valuable.     

Metastatic renal oncocytic neoplasm with benign histologic appearance

We present a case of malignant renal oncocytoma which displayed a benign histologic appearance in the primary renal tumor and in metastases to the spine and liver. The case demonstrates the difficulty that may be encountered in distinguishing benign renal oncocytomas from malignant renal oncocytomas. Whereas, the accepted criteria will enable a distinction in the majority of instances, occasional instances may be encountered in which a benign histology does not provide an accurate reflection on the clinical course.     

Caveolin expression in adult renal tumors

Histopathological criteria are usually sufficient for the accurate distinction of benign form malignant renal tumors. A minority of cases however, poses a vexing diagnostic dilemma. Recent studies suggest that caveolin, a scaffolding cell membrane protein may prove helpful in predicting the behavior of these neoplasms. We analyzed a series of 40 renal tumors of which 7 were clear cell and 6 granular Renal Cell Carcinomas (RCC), 10 cases of Papillary Carcinoma (PCC), 4 cases of Chromophobe Renal cell carcinomas (CRCR), 11 cases of Oncocytomas (OC) and 2 cases of Collecting Duct Carcinomas (CDC). The distribution of immunoreactivity was analyzed by quantifying caveolin cell membrane staining in each case. There was a statistically significant difference in the expression of caveolin-1 between oncocytoma with a mean labeling index of 91.7 and the cases of malignant renal tumors with a mean labeling index of 26.9 for RCC, 24 for CDC, 21 for CRCR, and 19.2 for PCC. The results suggest an association between loss of caveolin expression among malignant renal tumors that might be useful in distinguishing oncocytoma from malignant renal tumors and possibly implicates this peptide in their pathogenesis.     

肾嗜酸细胞腺瘤伴潜在恶性1例报告并文献复习

目的：探讨肾嗜酸细胞腺瘤的诊断、治疗和预后,提高肾嗜酸细胞腺瘤的诊疗水平。方法：对本院1例肾嗜酸细胞腺瘤患者的临床特点、治疗方法、病理特征以及治疗预后进行分析,并结合文献探讨其鉴别诊断及治疗预后。结果：影像学诊断为肾脏肿物,术后病理学检查为肾嗜酸细胞腺瘤,灶性侵犯肾实质,伴潜在恶性。对其实施根治性肾切除术并术后免疫治疗。结论：肾嗜酸细胞腺瘤是一种罕见的肾脏良性肿瘤,极少数潜在恶性或恶变,男女均可发病,术前诊断较困难易误诊为肾癌。治疗首选保留肾单位手术,对有潜在恶性和恶性的以肾癌治疗指南来进行,并且密切随访。     

Renal oncocytoma

The author reports on a case of renal oncocytoma, showing up as a side find, ing during autopsy. In the light microscopic picture of the tumour typical tubular alveolar, in some places solid arrangement was observed. The cytoplasm of the tumour cells could be characterized by even, subtle granulation. Malignant transformation was detected. It has been proved by electron microscopic examination that the granular appearance of the cytoplasm originated from mitochondria.In the light of the literary data the author underlines the rarity and the diagnostical importance of the alteration. Oncocytoma should be distinguished from granular, cellular cancer of the kidney and from malignant oncocytoma.     

Systemic vasculitis revealing a benign tumor: a paraneoplastic syndrome?

Systemic vasculitis is a rare event in the course of malignant tumors and has not been described in association with benign tumors. We report a case of renal oncocytoma in a patient who presented with digital necrosis, arthralgia, myalgia, and a decline in general health. The symptoms resolved fully after tumor excision, supporting a diagnosis of paraneoplastic syndrome.     

Molecular pathology of renal oncocytoma: A review

Differentiating renal oncocytoma from its renal cell carcinoma (RCC) mimics, particularly chromophobe RCC, can be difficult, especially when limited tissue is available for evaluation and requires sophisticated microscopic, ultrastructural and immunohistochemical evaluation. In this review, the relevant literature has been reviewed, and supporting data obtained by applying modern microarray‐based technologies are discussed with a focus on molecular pathology of renal oncocytoma. The high resolution whole‐genome DNA‐microarray based analyses excluded with all certainty the occurrence of small specific alterations. Renal oncocytomas are characterized by variable chromosomal patterns. The number of genes selected by global gene expression analyses and their usefulness in the diagnostic pathology based on immunohistochemical evaluation is far below the expectations. The conflicting staining patterns, together with the poor specificity of proposed antibodies, leads us to believe that these candidate immunomarkers might not help in the separation of these tumors. Applying DNA based tools might help in the diagnosis of renal oncocytoma with uncertain histology. However, only the combination of all available techniques could give reliable information.     

Chromosome anomalies suggestive of malignant transformation in bilateral renal oncocytoma

A patient with bilateral renal oncocytoma is presented, and the clinical, radiological and pathological characteristics of this uncommon, clinically benign renal tumor are discussed briefly. Chromosomal analysis studies revealed the following clonal abnormalities: trisomy of chromosome 7, and monosomy of chromosomes 3 and 14, and the X chromosome. A possible clonal abnormality of chromosome 10 and 3 nonclonal anomalies also were identified. The same anomalies were present in both tumors. These karyotypic anomalies are compatible with malignant transformation of the cells of these tumors and, since benign tumors rarely are associated with demonstrable cytogenetic changes, they suggest that oncocytoma, although clinically benign, may have malignant potential.     

Renal oncocytoma with synchronous contralateral renal cell carcinoma

We report a case of simultaneous contralateral oncocytoma and renal cell carcinoma. The diagnosis and prognosis of renal oncocytoma are discussed, and the management of bilateral renal tumors is reviewed.     

Oncocytoma in a horseshoe kidney

Renal oncocytoma is an unusual tumor that has been identified with increasing frequency during the last decade, and more than 150 cases have been reported in the literature, including multifocal and bilateral tumors. We report a case of oncocytoma in a horseshoe kidney. Oncocytoma and tumors in horseshoe kidneys are discussed.     

Bilateral kidney tumors: oncocytoma and adenocarcinoma. A case report

An unusual case of bilateral kidney tumors with two histologically different tumors, one right-sided oncocytoma and one left-sided renal cell carcinoma is described. The morphological features of the two tumors are briefly delineated. The diagnostic dilemma between an oncocytoma and a renal cell carcinoma is discussed.     

Primary malignant mesothelioma of the penis: case report and review of the literature

We present an unusual case of primary malignant mesothelioma of the penis in an adult male. The clinical features and microscopic, immunohistochemical, and ultrastructural characteristics that help to identify this entity are described. A discussion of the behavior of malignant mesothelioma follows, as well as a possible explanation for its origin in the penis. To date, no cases of primary malignant mesothelioma of the penis have been reported.     

Collecting duct carcinoma associated with oncocytoma

Collecting duct carcinoma (CDC) is a rare, highly aggressive malignant neoplasm that arises from the collecting duct epithelium of the kidney. CDC was reported to coexist with renal cell and transitional cell carcinomas. We report a rare case of CDC associated with oncocytoma, confirmed by the characteristic histological appearance and immunohistochemistry. We also review the epidemiological, histological and immunohistochemical criteria for diagnosis, in addition to the genetic and cytogenetic aberrations reported in the literature. Identification and reporting CDC is important for the establishment of treatment strategies and monitoring prognosis.     

Renal oncocytoma associated with necrotizing glomerulonephritis

A case of renal oncocytoma associated with focal segmental necrotizing glomerulonephritis is described. The patient showed haematuria, mild proteinuria and arterial hypertension; the diagnosis was made after right nephrectomy performed because of the presence of a renal mass. A severe re-activation of the glomerulonephritis was observed 15 months after the nephrectomy and a steroid and immunosuppressive therapy was started. Our case is the first reported in which the removal of renal oncocytoma is not followed by the disappearance of renal symptoms, as currently reported in literature, suggesting that the two diseases are not always related.     

RENAL ONCOCYTOMA CONTAINING "CHROMOPHOBE" CELLS

We report a rare case of renal oncocytoma containing occasional "chromophobe" cells. This case suggests an intimate relationship between oncocytoma and "chromophobe" renal cell carcinoma.     

A case of renal oncocytoma

A case of renal oncocytoma is reported. A 56-year-old woman was admitted with the complaint of an abdominal mass. Right transabdominal nephrectomy was performed on January 23, 1984. The resected kidney weighed 262 g and contained a well-demarcated 5 X 5 X 4 cm tumor in the middle portion. The cross section of the tumor was tan-brown. Light microscopic examination disclosed that the greater part of the tumor was composed of cells with abundant, and finely granular eosinophilic cytoplasm and with moderate nuclear pleomorphism. Electron microscopic examination confirmed that the cytoplasm had numerous mitochondria and few other organelles. According to these findings, the tumor was diagnosed as renal oncocytoma. Furthermore, it is noteworthy that in this case there were tubular arrangement of the cells resembling proximal renal tubules in a focal area and a group of cells with considerable nuclear atypia and hyperchromatism in another area. The patient has been well without any local recurrence or distant metastasis ten months after the operation. In addition, fourteen cases of renal oncocytoma in Japan, including the present case, are reviewed.     

Renal oncocytoma: diagnostic and therapeutic aspects

Renal oncocytoma is one of the most unusual benign lesions, which presents as a complicated mass resulting in a diagnostic and therapeutic dilemma. A new case of renal oncocytoma in a 13-year-old boy is presented. The clinocopathologic features of this rare entity are discussed, with special emphasis on diagnosis and treatment. There are no specific presumptive clinical and laboratory findings, including tumor markers, ploidy analysis, and imaging techniques that distinguish oncocytoma from other renal masses. The most important diagnostic aid is to bear this entity in mind when a child presents with an unexplained renal mass. Frozen section biopsies followed by partial nephrectomy are mandatory for the appropriate treatment after excluding bilateral or multifocal occurrence.