An oncocytic neoplasm refers to a type of growth composed of specific cells known as oncocytes. These growths can occur in various parts of the body and are characterized by the unique appearance of their constituent cells. Such neoplasms can be either non-cancerous (benign) or cancerous (malignant). Understanding these growths involves examining the cells that form them and how they behave within the body.
Understanding Oncocytes
Oncocytes are distinct cells recognized by their unusually large size and a cytoplasm that appears bright pink or eosinophilic when viewed under a microscope after staining. This characteristic pink color is due to an abundance of mitochondria, the cell’s energy-producing organelles, which also give the cytoplasm a granular appearance.
These specialized cells are often larger and more granular than surrounding cells in normal tissue. Oncocytes can be found in various tissues, sometimes in healthy conditions, but they are also a defining feature of oncocytic neoplasms. The accumulation of altered mitochondria can also lead to oncocytic changes, which involve cellular enlargement.
Common Locations and General Characteristics
Oncocytic neoplasms develop in several organs. They are frequently observed in the thyroid gland (sometimes called Hürthle cell tumors), kidneys (renal oncocytomas), salivary glands (particularly the parotid gland), and adrenal glands.
Macroscopically, benign oncocytic adenomas often appear as encapsulated, solid nodules. They sometimes have a characteristic brown cut surface, as seen in the thyroid.
Distinguishing Oncocytic Neoplasms
A primary concern when an oncocytic neoplasm is identified is determining whether it is benign or malignant. Benign oncocytic neoplasms, such as oncocytomas, are non-cancerous and typically do not invade nearby tissues or spread to other parts of the body. In contrast, malignant oncocytic neoplasms, also known as oncocytic carcinomas, have the potential to grow into surrounding tissues and may spread to distant sites.
Pathologists examine several features to differentiate between benign and malignant forms. They assess cellular atypia (abnormal cell characteristics), invasiveness (growth beyond normal boundaries), and mitotic activity (the rate at which cells are dividing). Even though oncocytomas are non-cancerous, they may be removed if they cause symptoms or if imaging studies cannot definitively distinguish them from cancerous growths.
Diagnosis and Management Approaches
The diagnostic process for an oncocytic neoplasm begins with imaging techniques. An ultrasound or CT scan can locate the growth and assess its size and characteristics. While imaging provides initial information, it cannot definitively determine the neoplasm’s nature.
Following imaging, a biopsy is performed. This involves taking a small tissue sample from the growth for microscopic examination by a pathologist. Pathological examination is the definitive method for diagnosis and determining if it is benign or malignant.
Once diagnosed, management strategies vary by neoplasm type and location. For benign oncocytic neoplasms, watchful waiting may be an option, especially if the growth is small and asymptomatic. Surgical removal is common for symptomatic benign growths, those difficult to distinguish from cancer, and all malignant oncocytic neoplasms to ensure complete removal.