An extremely rare case of interdigitating dendritic cell sarcoma of the parotid gland with a 40‑month disease‑free survival time after only surgery: A case report

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm arising from dendritic cells and is mainly located in the lymph nodes. To the best of our knowledge, no treatment strategy has yet been established for IDCS, despite its aggressive clinical features. The present study presents the case of a patient with IDCS who experienced a 40-month disease-free survival time after surgery alone. The patient, a 29-year-old woman, presented with a painful right subaural swelling. Diagnostic MRI and ¹⁸F-fludeoxyglucose positron emission tomography/computed tomography revealed a right parotid gland tumour and ipsilateral cervical lymph node. The patient underwent surgical resection, and histological examination of the resected tissue specimens confirmed IDCS diagnosis. To the best of our knowledge, this is only the fifth report of an IDCS located in the parotid gland, with the longest follow-up period among cases of IDCS reported in this region. The positive outcome of this patient suggests that surgical resection may be an effective treatment option for local IDCS. Nonetheless, further studies are required to establish a definitive diagnosis and treatment strategy for IDCS.