Attention first oncocytomas as benign kidney tumors after a series of cases reported by Klein and Valensi in 1976. They constitute about 3-5% of renal tumors in most large series. However, the tumor was similar to oncocytoma described above, Zippel et al. The term means oncocyte "Swollen cells" because of numerous cytoplasmic mitochondria. similar tumors may occur in the salivary glands, thyroid, parathyroid, adrenal and sites.
Pathology
Oncocytomas are well circumscribed, unencapsulated tumors with a characteristic central stellate scar, seen in 33%, most commonly in large tumors. The average size is about 5 cm, however, may be as large as 20 cm. The color is classically mahogany-brown, but can be brown to pale yellow. The bleeding may be seen in 20%. They are composed of solid nests and sheets with abundant eosinophilic cytoplasm oncocyte granular, residing in a stro edematous, mucopolysaccharide-rich extracellular evil of the matrix. Believed to be derived from collecting duct intercalated cells. The cores usually do not show pleomorphism, with a uniform dispersion of chromatin, central discrete nucleoli and mitotic activity are rare to absent. Features such as the perirenal fat, and lymphovascular invasion can be seen and seems to confer a worse prognosis.
However, "atypical" as the gross involvement of the renal vein, extensive papillary architecture, foci of clear cell sarcomatoid dedifferentiation, prominent necrosis and frequent or atypical mitosis have a different connotation and are incompatible with a diagnosis oncocytoma.
The most common differential diagnosis oncocytomas and chromophobe RCC are clear cell RCC with eosinophilic cells. The distinction between these tumors by aspiration cytology specimen can be difficult. Hale's colloidal iron, parvalbumin, and vimentin were negative (although luminal focal) compared with diffuse cytoplasmic iron, colloidal can be seen in oncocytomas and mitochondrial antibody was positive in oncocytoma and can help in the differential diagnosis. The electron microscope, characterized by the accounts of numerous mitochondria of normal appearance of cytoplasmic granularity, which leads to the use of the term "mitochondrioma" by some authors. Microvesicles seen in chromophobe RCC oncocytoma are absent.
Oncocytosis is a condition in which the kidneys contain oncocytomatous multifocal nodules with oncocytic changes in the renal tubules and cysts in the surrounding regions of the kidneys. Multifocality and bilaterality can occur in 5-13% of oncocytomas resected. It behaves similarly to solitary tumors. Sometimes an injury can contain both components oncocytomatous and chromophobe RCC, a condition known as "hybrid oncocytic tumor (tumor HOT)." Therefore, it is crucial to examine thoroughly and properly shows a lesion grossly resembles a oncocytoma. The coexistence of chromophobe RCC and oncocytoma with morphological similarities have sparked a debate about whether these two entities represent two ends of the spectrum, with a common origin of collecting duct intercalated cells. Recent molecular evidence suggests that renal oncocytoma and chromophobe RCC share some similarities not only morphological, but also the first cytogenetic abnormalities, including loss of chromosomes Y, 1, and 14
The Birt-Hogg-Dube syndrome is a family where the gene autosomaldominant, FSH has been located on the short arm of chromosome 17. This is characterized by skin papules domed in the facial area, renal tumors (27% of patients), lung cysts and spontaneous pneumothorax. The most common renal tumor is a hybrid of chromophobe RCC and oncocytoma with multiple tumors in the majority. The possibility of this familial syndrome should be entertained in a diagnosis of renal oncocytosis.
Clinical Presentation
Oncocytoma may occur anywhere between the ages of 14-90 years, without gender predilection. Mainly detected as an incidental finding on routine radiographic studies. Occasionally, patients may have hematuria, flank pain or a palpable mass. On CT, the lesion is usually hypodense, well-defined, peripheral location and a central scar. It has a "pattern of spokes of the wheel" on angiography.
Treatment and Prognosis
Current literature supports the benign nature of the disease, curative surgery to be. metachronous lesions were reported as late as 9 years after initial diagnosis. If the clinical data or information confirms preoperative oncocytoma can be safely treated by partial nephrectomy. Therefore, the preoperative diagnosis can prevent overtreatment. However, most patients undergo nephrectomy due to the inability of current diagnostic methods for reliably distinguish renal cell carcinoma, and occasional coexistence of RCC chromophobe and clear cell RCC with oncocytoma .
Pathology
Oncocytomas are well circumscribed, unencapsulated tumors with a characteristic central stellate scar, seen in 33%, most commonly in large tumors. The average size is about 5 cm, however, may be as large as 20 cm. The color is classically mahogany-brown, but can be brown to pale yellow. The bleeding may be seen in 20%. They are composed of solid nests and sheets with abundant eosinophilic cytoplasm oncocyte granular, residing in a stro edematous, mucopolysaccharide-rich extracellular evil of the matrix. Believed to be derived from collecting duct intercalated cells. The cores usually do not show pleomorphism, with a uniform dispersion of chromatin, central discrete nucleoli and mitotic activity are rare to absent. Features such as the perirenal fat, and lymphovascular invasion can be seen and seems to confer a worse prognosis.
However, "atypical" as the gross involvement of the renal vein, extensive papillary architecture, foci of clear cell sarcomatoid dedifferentiation, prominent necrosis and frequent or atypical mitosis have a different connotation and are incompatible with a diagnosis oncocytoma.
The most common differential diagnosis oncocytomas and chromophobe RCC are clear cell RCC with eosinophilic cells. The distinction between these tumors by aspiration cytology specimen can be difficult. Hale's colloidal iron, parvalbumin, and vimentin were negative (although luminal focal) compared with diffuse cytoplasmic iron, colloidal can be seen in oncocytomas and mitochondrial antibody was positive in oncocytoma and can help in the differential diagnosis. The electron microscope, characterized by the accounts of numerous mitochondria of normal appearance of cytoplasmic granularity, which leads to the use of the term "mitochondrioma" by some authors. Microvesicles seen in chromophobe RCC oncocytoma are absent.
Oncocytosis is a condition in which the kidneys contain oncocytomatous multifocal nodules with oncocytic changes in the renal tubules and cysts in the surrounding regions of the kidneys. Multifocality and bilaterality can occur in 5-13% of oncocytomas resected. It behaves similarly to solitary tumors. Sometimes an injury can contain both components oncocytomatous and chromophobe RCC, a condition known as "hybrid oncocytic tumor (tumor HOT)." Therefore, it is crucial to examine thoroughly and properly shows a lesion grossly resembles a oncocytoma. The coexistence of chromophobe RCC and oncocytoma with morphological similarities have sparked a debate about whether these two entities represent two ends of the spectrum, with a common origin of collecting duct intercalated cells. Recent molecular evidence suggests that renal oncocytoma and chromophobe RCC share some similarities not only morphological, but also the first cytogenetic abnormalities, including loss of chromosomes Y, 1, and 14
The Birt-Hogg-Dube syndrome is a family where the gene autosomaldominant, FSH has been located on the short arm of chromosome 17. This is characterized by skin papules domed in the facial area, renal tumors (27% of patients), lung cysts and spontaneous pneumothorax. The most common renal tumor is a hybrid of chromophobe RCC and oncocytoma with multiple tumors in the majority. The possibility of this familial syndrome should be entertained in a diagnosis of renal oncocytosis.
Clinical Presentation
Oncocytoma may occur anywhere between the ages of 14-90 years, without gender predilection. Mainly detected as an incidental finding on routine radiographic studies. Occasionally, patients may have hematuria, flank pain or a palpable mass. On CT, the lesion is usually hypodense, well-defined, peripheral location and a central scar. It has a "pattern of spokes of the wheel" on angiography.
Treatment and Prognosis
Current literature supports the benign nature of the disease, curative surgery to be. metachronous lesions were reported as late as 9 years after initial diagnosis. If the clinical data or information confirms preoperative oncocytoma can be safely treated by partial nephrectomy. Therefore, the preoperative diagnosis can prevent overtreatment. However, most patients undergo nephrectomy due to the inability of current diagnostic methods for reliably distinguish renal cell carcinoma, and occasional coexistence of RCC chromophobe and clear cell RCC with oncocytoma .