Preoperative fine needle aspiration cytologic diagnosis of spindle cell myoepithelioma of the parotid gland: a case report

BACKGROUND: There are only rare case reports of preoperative fine needle aspiration cytologic (FNAC) diagnosis of myoepithelioma of the salivary gland. Myoepitheliomas with pure spindle cell morphology may simulate a variety of benign or malignant spindle cell soft tissue tumors. CASE: A 54-year-old woman presented with a history of progressively increasing swelling in the right parotid region. The clinical diagnosis was parotid malignancy. Routine FNAC yielded highly particulate material. The smears were cellular, with tissue fragments, clusters of spindle cells and numerous small globules and strands of bright magenta material. High cellular yield and pure spindle cell population with an accentuated chromatin pattern in Papanicolaou-stained smears simulated a low-grade spindle cell soft tissue sarcoma. A vague resemblance to a schwannoma was also noted. However, based on the characteristic findings of the May-Grünwald-Giemsa (MGG)-stained smears, a preoperative diagnosis of myoepithelioma was made and confirmed by subsequent histopathologic examination and immunohistochemistry. CONCLUSION: Cytologically, spindle cell myoepithelioma of the salivary gland may simulate low-grade spindle cell soft tissue sarcoma or schwannoma. However, optimal sampling of the lesion and logical interpretation of the MGG-stained smears, in the appropriate clinical situation, allow a confident preoperative diagnosis of these tumors.