Background: Spindle cell neuroendocrine carcinomas of the lung may be frequently observed on fine needle cytology (FNC) samples and often pose stimulating differential diagnostic problems.
Case: The cytopathologic findings from FNC performed on a long-standing coin lesion of the lung in a 54-year-old woman were analyzed in view of the data and long clinical history.
Conclusion: A final diagnosis of low grade spindle cell neuroendocrine carcinoma was reached by combining cytopathologic and immunocytochemical information. The main lesions considered in the differential diagnosis were intrapulmonary inflammatory myofibroblastic tumor (fibrohistiocytic variant) and spindle cell thymoma.