Cytological features of melanoma in exfoliative fluid specimens

• Published in: Journal of clinical pathology Vol. 62; no. 7; pp. 638 - 643
• Main Authors: Murali, R, Loughman, N T, McKenzie, P R, Watson, G F, Thompson, J F, Scolyer, R A
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and Association of Clinical Pathologists 01.07.2009; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adenocarcinoma - diagnosis; Aged; Aged, 80 and over; Biological and medical sciences; Body Fluids - cytology; Cytodiagnosis; Dermatology; Diagnosis, Differential; Diagnostic Errors; Epithelial Cells - pathology; Female; Fluids; Histiocytes - pathology; Humans; Information systems; Investigative techniques, diagnostic techniques (general aspects); Laboratories; Male; Medical sciences; Melanoma; Melanoma - diagnosis; Melanoma - pathology; Melanoma - secondary; Metastasis; Middle Aged; Morphology; Pathology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Sensitivity and Specificity; Skin; Skin Neoplasms - pathology; Tumors; Tumors of the skin and soft tissue. Premalignant lesions; Anatomic pathology; Malignant tumor; Cytology; Malignant melanoma; Cancer
• ISSN: 0021-9746; 1472-4146
• DOI: 10.1136/jcp.2009.065599

Aims:To describe the cytological appearances of melanoma in fluid specimens and potential diagnostic pitfalls in interpreting such specimens, which have been infrequently reported in the literature.Methods:Cases of melanoma diagnosed at a single institution between 1993 and 2008 in cytology specimens of fluids (pleural, ascitic, cerebrospinal and other fluids), but excluding fine needle biopsy specimens, were identified and reviewed.Results:32 fluid specimens containing metastatic melanoma (from 26 patients) were identified. Most of the specimens were moderately cellular and showed moderate to marked nuclear pleomorphism. Mitotic figures and intranuclear cytoplasmic invaginations were identified in 11 (34.4%) and seven (21.9%) cases, respectively. Melanin pigment was seen in eight (25.0%) cases. Variable numbers of histiocytes were present, and mesothelial cells were present in body cavity fluid specimens.Conclusions:In fluid specimens, reactive mesothelial cells and histiocytes may mimic epithelioid melanoma cells. Awareness of the morphological features and diagnostic pitfalls of melanoma in fluids is necessary to avoid the potentially serious consequences of misdiagnosis.