Nuclear moulding

Nuclear moulding in pathology

Nuclear moulding is a histopathological feature observed in certain types of cancer cells, where the nuclei of adjacent cells appear to conform to each other's shapes. This phenomenon is particularly characteristic of small cell lung carcinoma (SCLC), a type of lung cancer known for its aggressive behavior and poor prognosis.

Characteristics

Nuclear moulding occurs when the nuclei of tumor cells are closely packed together, often due to the high cellularity and scant cytoplasm typical of certain malignancies. This close apposition causes the nuclei to indent and conform to the shapes of neighboring nuclei, creating a "moulded" appearance. This feature is most commonly associated with small cell lung carcinoma but can also be seen in other high-grade neuroendocrine tumors.

Pathological Significance

In the context of pathology, nuclear moulding is an important diagnostic clue. It helps pathologists differentiate small cell lung carcinoma from other types of lung cancer, such as non-small cell lung carcinoma (NSCLC). The presence of nuclear moulding, along with other features like high mitotic rate, necrosis, and scant cytoplasm, supports the diagnosis of SCLC.

Associated Conditions

While nuclear moulding is most commonly associated with small cell lung carcinoma, it can also be observed in other conditions, including:

• Merkel cell carcinoma
• Lymphoma
• Certain types of neuroendocrine tumors

Histological Examination

Under the microscope, nuclear moulding is best appreciated in cytological preparations, such as fine needle aspiration biopsies or smears. The nuclei appear hyperchromatic and overlap each other, with the nuclear contours adapting to the shapes of adjacent nuclei.

Small cell lung cancer cytology showing nuclear moulding

Clinical Implications

The identification of nuclear moulding in a biopsy or cytology specimen can have significant clinical implications. It aids in the accurate classification of lung cancer, which is crucial for determining the appropriate treatment strategy. Small cell lung carcinoma, characterized by nuclear moulding, typically requires a different therapeutic approach compared to non-small cell lung carcinoma.

Related pages

• Small cell lung carcinoma
• Lung cancer
• Pathology
• Cytology