Spindle cell melanoma: a comparison of the cytomorphological features with the epithelioid variant

Fine-needle aspiration cytology serves as a rapid and cost-effective tool for the diagnosis of melanoma, especially in the recurrent and metastatic cases. The diagnosis poses a challenge due to the varied morphological patterns. Spindle cell melanoma mimics other sarcomas and carcinomas on morphology. This study highlights the cytomorphological features of spindle cell melanoma and compares them with the conventional epithelioid type.

Cytology smears of 55 aspirates from 45 diagnosed cases of melanoma from various sites were reviewed. Histopathology correlation was done in spindle and mixed cell tumors.

Melanomas with a pure or mixed spindle cell component occurred in 31% of the cases and in a slightly higher age group. These demonstrated prominent cellular cohesion (p < 0.0001), mild to moderate nuclear atypia and inconspicuous to small nucleoli as compared to the epithelioid variant. The presence of melanin pigment was a useful clue to the diagnosis. Most of the cases correlated well with the histomorphology.

Spindle cell melanoma is a morphological variant which can be readily misinterpreted due to a lack of classical cytological features of melanoma. Hence, these are vulnerable to be misinterpreted as other neoplasms. An awareness of clinical and cytological features is important to reach the correct diagnosis.