The lungs are a very common site for metastasis. Metastases are diagnosed in sputum in up to 70% of cases.
- Squamous carcinomas from aerodigestive tract
- Breast carcinoma
- Renal cell carcinoma
- Adenocarcinomas from digestive tract
- Bladder carcinoma
- Male and female genital tract malignancies
- Thyroid carcinoma
- Hematopoietic malignancies
Confirming metastatic disease is a major indication for transthoracic FNA.
Primary sites for some metastatic tumors can be inferred based on their characteristic cytologic features, but the clinical history is particularly important. Tissue-specific markers can be assessed on cell block preparations; immunocytochemistry is often helpful in distinguishing primary from metastatic disease and in identifying the origin of metastasis.
Signet ring carcinoma:
Renal clear cell carcinoma:
Oncocytic thyroid carcinoma:
Metastatic epidermoid carcinoma:
Metastatic breast carcinoma: