Fine-needle aspiration cytology features of a recurring plexiform fibrohistiocytic tumor in the upper limb and review of the literature

Approach to Fine Needle Aspiration of Giant Cell-rich Tumors of Soft Tissue

Giant cells may be found in a wide variety of reactive and neoplastic soft tissue lesions. Because of their distinct histomorphology, they often stand out in procured samples such as fine needle aspirates. The giant cells themselves may be benign or neoplastic. However, the presence, type, and quantity of giant cells are usually not specific and in some cases can even be misleading when making a diagnosis. The aim of this review is to guide the practicing cytopathologist in narrowing their differential diagnosis when encountering one of these challenging giant cell-rich lesions of the soft tissue.

Plexiform fibrohistiocytic tumor on the chest of a 5-year-old child and review of the literature

Plexiform fibrohistiocytic tumor (PFT) is a rare neoplasm of mesenchymal origin that can be identified by its propensity for children and adolescents combined with a characteristic histologic arrangement of histiocytes and osteoclast-like giant cells whorled within tumor islands. A 5-year-old female presented with a raised, intermittently tender, and slowly enlarging tumor on her chest, which was histologically confirmed to be a PFT. We present this case along with a comprehensive review of PFT cases reported in the literature to describe the demographic, histologic, and rarely metastatic behavior of this entity. It is important to include PFT on the differential diagnosis of an enlarging tumor in the pediatric population.

Plexiform Fibrohistiocytic Tumor Presenting as a Central Neck Mass Clinically Mimicking a Thyroglossal Duct Cyst: An Unusual Case Reported with Histo-cytopathologic Correlation and a Review of the Cytopathology Literature

We present the case of an uncommon example of a plexiform fibrohistiocytic tumor (PFHT) occurring in the anterior central neck region of a 40 year-old female with previous subtotal thyroidectomy. The tumor clinically mimics a complicated thyroglossal duct cyst. On fine needle aspiration cytology, the tumor was composed of sheets of bland spindle cells and nests of plump histiocytoid cells in vaguely whorled arrangements. Occasional multinucleated giant cells were also identified. The excised specimen showed an irregular, highly infiltrative subcutaneous tumor arranged in a nodular/plexiform pattern concentrated to the center of the tumor mass. In addition, the tumor contained numerous tongue-like extensions composed of variably cellular, fibroblastic/fibromatosis-like areas. These fibroblastic/fibromatosis-like extensions reached far from the epicenter of the tumor and were associated with scattered small plexiform nodules of histiocytic cells. These tongue-like extensions multifocally involved the surgical margins. The fibroblastic and histiocytoid cells showed diffuse smooth muscle actin (SMA) expression. The multinucleated giant cells and also the histiocytoid proliferation were positive for CD68. This case illustrates an uncommon both anatomical and demographic manifestation of PFHT and also characterize the fine needle aspiration cytologic features in this tumor, which previously have been reported in a few cases.