Fine-needle aspiration cytology of intranodal palisaded myofibroblastoma of the inguinal lymph node

Background: Intranodal palisaded myofibroblastoma (IPM) is a rare, lymph node mesenchymal neoplasm; the cytologic features are limited in the literature. Case: The patient was a 51-year-old female who had a firm, palpable mass in the right inguinal region. Fine-needle aspiration (FNA) was performed. The smears revealed large, 3-dimensional clusters of cohesive spindle cells, densely surrounding a central, orange-colored, acellular matrix core. These cells had a single, elongated nucleus and an inconspicuous nucleolus. Also seen were spindle cells in short fascicles with dense cytoplasm. The spindle cells were loosely arranged in a single-cell pattern. In addition to the spindle cells and matrix, hemosiderin granules were scattered in the background. A few lymphocytes were identified. Conclusion: A diagnosis of IPM should be considered when FNA smears of lymph node show bland spindle cells in various patterns including single cells, short fascicles, large cohesive clusters with core amianthoid fibers and background hemosiderin granules.