Concurrent Warthin tumor and Kimura disease: a case report.

BACKGROUND: Warthin tumor (WT) is a common benign salivary tumor of the parotid gland. Clinically, it occurs in men in their fifth to seventh decades who typically smoke cigarettes. WTs have been reported with different head and neck neoplasms and other salivary gland tumors within the same or another salivary gland. Kimura disease (KD) is a rare chronic inflammatory disease with unknown etiology affecting young to middle-aged Asian men. KD presents as an asymptomatic nodule in the head and neck area, with regional lymphadenopathy and salivary gland involvement. CASE PRESENTATION: A 64-year-old Arabic man presented with a 10-year history of an asymptomatic swelling of the left face. Computed tomography showed a well-defined, multicystic mass with heterogeneous enhancement. The resected mass was composed of two distinct components. There was a well-demarcated proliferation of papillary and cystic oncocytic epithelium with lymphoid stroma, consistent with WT. Some areas exhibited sclerotic fibrosis, with multiple lymphoid follicles showing folliculolysis, follicular hyperplasia, and eosinophilic infiltrate. The patient's immunoglobulin E level serum was elevated, confirming a coexisting KD. The patient underwent a left superficial parotidectomy, with no recurrence at a 30-month follow-up. CONCLUSION: This report describes the first concurrent case of WT and KD in the parotid gland.

Low-Grade Fibromyxoid Sarcoma Featuring an Unusual EWSR1-CREB3L2 Gene Fusion: Report of a Rare Case Arising in the Parotid Gland.

Low-grade fibromyxoid sarcoma (LGFMS), also known as Evan's tumor, is a fibroblastic tumor with a deceptively bland morphology but a high metastasizing potential and late recurrence. It presents clinically as a slowly growing mass in the deep soft tissue of extremities and trunk. Morphologically, it shows a biphasic pattern with alternating fibrous and myxoid areas, whorling growth pattern, hypocellularity, and bland fibroblasts with curvilinear or arcuate vessels in between. Collagen rosettes with central hyalinization is a helpful feature but not specific. MUC-4 is the most sensitive immunostain in LGFMS. The majority of cases harbor a gene fusion in FUS - CREB3L2. Herein, we present a 23-year-old female patient with a slow growing painless mass in the left parotid gland, which was later diagnosed as LGFMS. Involvement of the head and neck region by LGFMS is uncommonly encountered. To date, only two cases within the parotid gland have been described.