Fine needle aspiration cytolog of perineal alveolar rhabdomyosarcoma: cytohistopathologic and immunocytochemical correlations.

Objective: To describe the cytopathologic findings in a case of alveolar rhabdomyosarcoma (ARMS) of the perineum in a 13-year-old girl and to compare the cytopathologic findings with the histopathologic and immunohistochemical features observed on the corresponding fragments obtained from core biopsy of the mass.

Study Design: The cytopathologic findings observed in fine needle aspiration biopsy of a vulvar mass were analyzed with reference to their predictive diagnostic value in pathologic evaluation of the lesion.

Results: Following a prospective cytopathologic diagnosis of ARMS, a cutting needle core biopsy was performed. Histopathologic and immunohistochemical study of the tissue fragments confirmed the cytopathologic diagnosis.

Conclusion: Careful cytopathologic evaluation of optimal cell samples from ARMS may elicit a correct diagnosis provided that immunocytochemical staining for markers of myogenic differentiation is performed in a pretherapeutic phase.