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Papillary formations in metastatic melanoma
1Department of Pathology and Laboratory Medicine, University of Pennsylvania Medical Center, Philadelphia 19104, USA. baloch@mail.med.upenn.edu
Diagnostic Cytopathology
|March 23, 1999
Summary
Metastatic melanoma can present with unusual papillary structures in fine-needle aspiration (FNA) samples, mimicking other cancers. Recognizing these distinct cytomorphologic features is crucial for accurate diagnosis and avoiding misinterpretation of melanoma.
Area of Science:
- Oncology
- Cytopathology
Background:
- Metastatic melanoma exhibits diverse cytomorphologic features.
- Accurate diagnosis of metastatic melanoma is critical for patient management.
Observation:
- Ten cases of metastatic melanoma with distinct, cohesive, papillary tissue fragments in fine-needle aspiration (FNA) specimens were analyzed.
- These fragments featured a central fibrovascular core with attached tumor cells, alongside scattered malignant cells, macrophages, and necrosis.
- Aspiration sites included lymph nodes, pancreas, bone, and skin.
Findings:
- Immunohistochemical studies (S-100 protein, HMB-45 antigen, factor VIII) and electron microscopy confirmed melanoma diagnosis.
- Nine cases had primary cutaneous melanoma; one had the primary detected post-metastasis diagnosis via FNA.
- The papillary formations were a distinct cytomorphologic variation in metastatic melanoma.
Implications:
- Awareness of these papillary formations in cytology is essential for accurate interpretation.
- This cytomorphologic variation can prevent misdiagnosis of metastatic melanoma.
- Understanding these features aids in distinguishing melanoma from other poorly differentiated neoplasms.