Fine-needle aspiration cytopathology of soft tissue myoepithelioma: an analysis of seven cases.

TitleFine-needle aspiration cytopathology of soft tissue myoepithelioma: an analysis of seven cases.
Publication TypeJournal Article
Year of Publication2022
AuthorsWakely PE, Siddiqui MT
JournalJ Am Soc Cytopathol
Volume11
Issue1
Pagination31-39
Date Published2022 Jan-Feb
ISSN2213-2945
KeywordsAdult, Aged, Biopsy, Fine-Needle, Chondrosarcoma, Female, Humans, Male, Middle Aged, Myoepithelioma, Neoplasms, Connective and Soft Tissue, Sarcoma, Soft Tissue Neoplasms
Abstract

INTRODUCTION: Soft tissue myoepithelioma (STM), a rare mesenchymal neoplasm morphologically analogous to its more common salivary gland (SG) counterpart, is the subject of single case reports regarding its fine-needle aspiration (FNA) biopsy. To our knowledge, ours is the first case series of STM.

MATERIALS AND METHODS: A search was made of our pathology databases for cases diagnosed as STM. FNA biopsy smears and cell blocks were performed using standard techniques.

RESULTS: Seven cases were retrieved from 4 men and 3 women (M:F = 1.3:1; age range: 25-79 years, x = 54 years). All but 1 presented as a primary neoplasm. Six aspirates were from the extremities, and 1 from the abdominal wall. Mean tumor size was 5.7 cm. Cytologic diagnosis of STM or suspicious for STM was made in 3 cases (43%). Remaining FNA diagnoses were spindle cell neoplasm/lesion (2), spindle cell sarcoma (1), and extraskeletal myxoid chondrosarcoma (1). Three cases were composed primarily or solely of uniform spindle cells, 3 primarily of uniform epithelioid cells with plasmacytoid features, and 1 case a mixture of these 2 cell types. Myxoid/chondromyxoid stroma was relatively abundant except in the single hypocellular example. Immunohistochemical (IHC) testing performed in 71% was nonspecific, but positive with S-100 in 4 of 5, EMA in 3 of 3, calponin in 2 of 2, and keratin in 1 of 3 examples.

CONCLUSION: FNA biopsy smears of STM are remarkably similar cytomorphologically to their SG equivalent. However, STM can be misidentified principally as extraskeletal myxoid chondrosarcoma, thus requiring a relatively broad IHC panel for a specific diagnosis.

DOI10.1016/j.jasc.2021.09.001
Alternate JournalJ Am Soc Cytopathol
PubMed ID34649776
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Momin Siddiqui, M.D.

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