Dendritic cell tumor in a salivary gland lymph node: a rare differential diagnosis of salivary gland neoplasms

The patient underwent complete tumor resection, and is currently free of disease, 2 years after surgery. These extremely rare tumors must be distinguished from other more common tumors in the salivary glands. Awareness that dendritic cell tumors may occur in this localization, careful histologic evaluation and ancillary immunohistochemical and electron microscopical analyses should allow for recognition of this entity.The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1614859498581601 webcite.Dendritic cell sarcomas (DCS) are exceedingly rare entities, arising from antigen-presenting cells of the immune system. DCS are subclassified into the better characterized follicular (FDCS) [1] and interdigitating (IDCS) [2] dendritic cell sarcomas and other rare and less well classifiable dendritic cell tumors like fibroblastic reticular cell tumors, indeterminate dendritic cell tumors and dendritic cell tumors, not otherwise specified (DCT, NOS) [2]. DCS was first described in 1986 by Monda et al. [3]. Since then, nearly 300 cases, most of them FDCS, have been described in the literature. Although most DCS evolve in cervical, mediastinal, axillary and inguinal lymph nodes, also extranodal manifestations have been described [4]. The clinical behaviour of DCS is similar to that of low-grade soft tissue sarcoma, with an approximately 30% overall risk for developing local recurrences and metastases [5]. Because of the rareness of the disease a standardized treatment is lacking.We herein report a case of a dendritic cell tumor, NOS of an intraparotideal lymph node, emphasizing the important role of ancillary immunohistochemical and molecular studies in establishing this extraordinarily rare diagnosis.A 69-year-old man presented with a 2-months history of a gradually enlarging painless, firm, mobile, 2 × 2 × 2 cm swelling at the caudal pole of the left parotid gland without systemic symptoms. His medical history was unremarkable.