Head and Neck Extranodal Interdigitating Dendritic Cell Sarcoma: Case Report and Review of the Literature.

Interdigitating dendritic cell sarcoma (IDCS) is an exceedingly rare neoplasm originating from professional antigen presenting cells normally located in the T zone of the lymph node. The purpose of this report was to describe the first case of the IDCS of the submandibular gland and perform a review of the literature of head and neck IDCS. We present a case of an 81-year-old man with a 5 months history of slowly enlarging painless mass in right submandibular region. Fine needle aspiration cytology was suggestive of squamous cell carcinoma. The patient underwent surgical resection of the right submandibular gland and neck dissection. A malignant spindle cell proliferation involving the submandibular gland and colonizing one laterocervical lymph node was found. Morphology and immunophenotype prompted a differential diagnosis of a metastatic spindle cell melanoma versus an IDCS. Transmission electron microscopy was performed and supported a diagnosis of IDCS. The diagnosis of IDCS is a challenging task and may require a large array of techniques.