Diffuse Oncocytosis Research Articles

Mitochondrial DNA mutations distinguish bilateral multifocal renal oncocytomas from familial Birt–Hogg–Dubé tumors

Oncocytomas are mostly benign tumors characterized by accumulation of defective mitochondria, and in sporadic cases, are associated with disruptive mitochondrial DNA (mtDNA) mutations. However, the role mtDNA mutations have in renal tumors of Birt–Hogg–Dubé (BHD) patients and other renal oncocytomas with an apparent genetic component has not been investigated to date. Here we characterize the mitochondrial genome in different renal tumors and investigate the possibility of employing mtDNA sequencing analyses of biopsy specimens to aid in the differential diagnosis of oncocytomas. The entire mitochondrial genome was sequenced in 25 samples of bilateral and multifocal (BMF) renal oncocytomas, 30 renal tumors from BHD patients and 36 non-oncocytic renal tumors of different histologies as well as in biopsy samples of kidney tumors. mtDNA sequencing in BMF oncocytomas revealed that all tumors carry disruptive mutations, which impair the assembly of the NADH-ubiquinone oxidoreductase. Multiple tumors from a given BMF oncocytoma patient mainly harbor the same somatic mutation and the kidneys of these patients display diffuse oncocytosis. In contrast, renal oncocytomas of patients with BHD syndrome and renal tumors with different histologies do not show disruptive mtDNA mutations. Moreover, we demonstrate that it is feasible to amplify and sequence the entire mtDNA in biopsy specimens, and that these sequences are representative of the tumor DNA. These results show that pathogenic mtDNA mutations affecting complex I of the respiratory chain are strongly correlated with the oncocytoma phenotype in non-BHD-related renal tumors and that mtDNA sequences from biopsies are predictive of the tumor genotype. This work supports a role for mtDNA mutations in respiratory chain complexes as diagnostic markers for renal oncocytomas.

L'hyperplasie oncocytaire nodulaire multifocale de la glande parotide

Objectives Oncocytic lesions rarely affect the parotid gland, accounting for less than 1% of all salivary lesions. The WHO classification described three main types: diffuse oncocytosis, focal nodular oncocytosis hyperplasia, and oncocytoma. Multifocal nodular oncocytosis hyperplasia of the parotid gland represents an extremely rare, non-tumorous pathology of the parotid gland. Material and methods We report a case of multifocal nodular oncocytosis hyperplasia of the parotid gland in a 70-year-old woman who was referred for a left preauricular mass that had gradually increased in size over the last 2 years. No lymph node of the neck was palpable. Results MRI demonstrated multiple bilateral lesions of the parotid glands. Total parotidectomy, preserving the facial nerve, was performed. Conclusion We discuss the physiopathology and the treatment of multifocal nodular oncocytosis hyperplasia and provide a review of the literature.

Multifocal adenomatous oncocytic hyperplasia of the parotid gland

Oncocytes appear as the principal component in some pathological conditions of the salivary glands including diffuse oncocytosis, oncocytic metaplasia, oncocytoma, oncocytic carcinoma, and multifocal adenomatous oncocytic hyperplasia. Oncocytic tumors rarely affect the major salivary glands, accounting less than 1% of all salivary gland tumours. Multifocal adenomatous oncocytic hyperplasia in the salivary glands is an extremely rare condition. The differential diagnosis of the clear cell variant includes many malignant salivary gland tumors. We report a new case of multifocal adenomatous oncocytic hyperplasia of the parotid gland in a 64-year-old man. The differential histopathogenesis, diagnosis, and treatment of this rare entity are discussed.

Diffuse hyperplastic oncocytosis of the parotid gland

Oncocytic tumours rarely affect the major salivary glands, accounting for less than 1% of all salivary-gland tumours. The World Health Organisation classification groups these tumours into three principal types: diffuse oncocytosis, focal adenomatous oncocytic hyperplasia and oncocytoma. Diffuse hyperplastic oncocytosis is the rarest lesion: only six cases have been previously reported in the literature. This condition of putative hyperplastic pathogenesis follows a benign course, whereas oncocytomas may recur after excision. No metastatic dissemination or recurrence of diffuse hyperplastic oncocytosis has been reported. We present and discuss a new case of diffuse hyperplastic oncocytosis of the parotid gland.

Tumour-like Lesions of the Salivary Glands: The New VMO Classification

Tumour-like lesions must be distinguished from true tumours of the salivary glands. In the new WHO classification of salivary gland tumours seven entities were considered: sialadenosis, oncocytosis (diffuse oncocytosis and focal adenomatous oncocytic hyperplasia), necrotizing sialometaplasia (salivary gland infarction), benign lymphoepithelial lesion (chronic myoepithelial sialadenitis), salivary duct cysts (mucoceles of the minor salivary glands of extravasation or retention type, cysts of the major salivary glands, ranula and dysgenetic polycystic disease of the parotid gland), chronic sclerosing sialadenitis of the submandibular gland (Küttner tumour), and cystic lymphoid hyperplasia in AIDS. The main topics of clinical data and pathohistology were described and documented by the results of the Salivary Gland Register in Hamburg (1965-1989).

Oncocytic adenomas and oncocytic hyperplasia of salivary glands: a clinicopathological study of 26 cases

Twenty-six benign oncocytic lesions of the salivary glands, excluding Warthin's tumours, have been reviewed and criteria for their classification as oncocytoma, multifocal nodular oncocytic hyperplasia, diffuse oncocytosis, pleomorphic adenoma with oncocytic change or oncocytic monomorphic adenoma have been proposed. The histological and clinical features of this heterogeneous group of lesions are discussed. This analysis suggests that the majority of lesions initially categorized as oncocytomas were, in fact, either non-neoplastic or, alternatively, oncocytic change in other types of adenoma.