Classification of Ragazzi et al for Mitochondrial Content of Oncocytic and Other Invasive Breast Carcinomas

 

Oncocytic cells have abundant, granular eosinophilic cytoplasm due to a high number of mitochondria.

Percent of Tumor Cells Staining with AMA	Designation
>= 70% as 3+ (strong)	oncocytic
>= 50% as 2+ (moderate) or 3+ strong, not oncocytic	mitochondrion-rich

 

where:

• Staining is strong when it is the same as oncocytic cells in a Warthin tumor.

• Staining is moderate when it is the same as cells of striated ducts that are rich in mitochondria.

 

An invasive carcinoma that did not meet either of these designations was termed not mitochondrion-rich.

 

Most oncoyctic and mitochondrion-rich carcinomas are high grade (Grade III) and overexpress HER2 (human epidermal growth factor receptor 2).