bromochloroacetic-acid and Histiocytic-Disorders--Malignant

Fibroblastic reticulum cell tumor (FRCT) is a rare dendritic neoplasm arising from fibroblastic reticulum cells (FBRCs) and exhibiting peculiar cytokeratin expression. FRCTs usually involve the lymph nodes, although they can also be encountered in the spleen and soft tissues. FRCTs are composed of mildly atypical spindle or ovoid cells, arranged in loose whorls, which express almost invariably low-weight cytokeratins, smooth muscle actin, and CD68. An admixed lymphoplasmacytic infiltrate is also frequently present in solid organ sites. The clinical picture may vary from very indolent to aggressive disease exhibiting features of malignancy, such as cytological pleomorphism, necrosis, or high mitotic rate and metastatic potential. FRCT is a challenging diagnosis, due to its rarity and deceptive cytokeratin expression. Hereafter, we revise the most recent literature regarding such condition and report the case of an extremely indolent splenic FRCT, with no features of malignancy.

Topics: Histiocytic Disorders, Malignant; Humans; Keratins; Neoplasms; Splenic Neoplasms

Fibroblastic reticular cell (FRC) neoplasms, which are one of the histiocyte tumor types, are very rare. Here we report a cytokeratin (CK)-positive FRC neoplasm having features of follicular dendritic cells in a 54-year-old woman with right axillary lymph node swelling. The resected lymph node showed multiple nodular aggregations simulating and replacing normal follicles. The tumor cells had a uniform, large and oval to polygonal shape, abundant cytoplasm, and various sizes of nuclei with central eosinophilic nucleoli and coarse nuclear chromatin. They were positive for CK AE1/AE3+CAM5.2, CK7, tenascin C, l-caldesomone, and CD21, weakly positive for S100, and negative for CD1a. Ultrastructurally, the tumor cells had long interdigitating microvillus-like cell processes and oval to elongated vesicular nuclei. In addition, the intercellular spaces contained accumulations of collagen, and some tumor cells had desmosomal-like junctions. These findings suggest that the present case is a CK-positive FRC tumor with follicular dendritic cell features.

Topics: Biomarkers, Tumor; Biopsy; Dendritic Cells, Follicular; Female; Histiocytic Disorders, Malignant; Humans; Immunohistochemistry; Karyotyping; Keratins; Lymph Node Excision; Lymph Nodes; Microscopy, Electron; Middle Aged; Positron-Emission Tomography; Stromal Cells; Tomography, X-Ray Computed; Treatment Outcome