On further questioning, the patient confirmed a previous history of melanoma excised 9 years earlier from the right supraclavicular fossa with clear margins. No disease in the intervening years.
The fluid from the chest drain was sent for cytology.
Cytology
MACROSCOPIC DESCRIPTION: 80ml moderately bloodstained fluid.
MICROSCOPIC DESCRIPTION: The smears are cellular, containing numerous abnormal epithelioid cells. They have pleomorphic nuclei, bi/multinucleation, coarse chromatin, occasional intranuclear pseudoinclusions and moderate amounts of cytoplasm. No pigment is seen.
FINAL DIAGNOSIS: Positive for malignancy, in keeping with metastatic melanoma.