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A 15-year-old old Japanese male with a 2-month history of swelling of his left subauricular area was admitted to our department. A thumb-sized, hard mass with mild tenderness was palpated on the left parotid gland. Ultrasonography revealed a well-circumscribed, hypoechoic mass exhibiting heterogeneity in the left parotid gland measuring 1.7 × 1.5 × 1.3 cm. Computed tomography scan revealed a well-circumscribed, solid mass exhibiting slight peripheral enhancement in the left parotid gland. Magnetic resonance imaging revealed a hypointense mass in the left parotid gland on both T1- and T2-weighted images. Clinicoradiologic findings suggested a benign or low-grade malignant parotid tumor. The patient underwent left superficial parotidectomy with adequate safety margins. The facial nerve was identified and preserved. Neither facial paralysis nor tumor recurrence was observed as of 1 year postoperatively. Histologically, the nodule consisted of a vaguely nodular arrangement of variably sized ducts and acini in a hyalinized fibrous background with focal myxoid changes. The ductal/acinar component exhibited a bilayered arrangement of cuboidal luminal and flattened abluminal cells exhibiting a variety of epithelial proliferative patterns, including micropapillary and cribriform. Areas of oncocyte-like changes with intracellular coarse eosinophilic granules, apocrine-like feature, foamy/vacuolated changes, and clear cells were noted in the proliferating epithelium. Immunohistologically, the luminal cells were positive for gross cystic disease fluid protein-15. The Ki-67 labeling index was 2-3%. The histologic features and immunohistologic profile were consistent with sclerosing polycystic adenosis. Targeted next-generation sequencing of 160 cancer-related genes using the surgical specimen revealed no mutations, including known significant mutations in PTEN, PIK3CA, or PIK3R1., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A 52-year-old man with a 2-year history of left buccal swelling was admitted to our department. An elastic hard oral mass was palpated under the intact buccal mucosa. A CT scan with enhancement revealed a solid mass measuring 2.0 × 1.5 × 1.3 cm between the left masseter muscle and the maxilla. Laboratory examination showed elevated peripheral blood eosinophil count of 1070/μL (12.3%) and serum immunoglobulin (Ig)E level of 1374 IU/mL. Histologic examination of transorally excised mass revealed lymphoid follicular hyperplasia with reactive germinal centers and eosinophilic infiltration with eosinophilic micro-abscesses in the germinal centers. Abundant IgE deposition in a reticular fashion was observed in the germinal centers and c-kit positive mast cells was observed in the paracortical area in the excised mass. The patient was diagnosed with Kimura disease (KD) and treated with oral prednisolone, tapering from 10 mg/day for approximately 8 months. Eosinophil count and serum IgE level decreased to 435/μL (5%) and 520 IU/dL, respectively. He is free from symptoms at the time of this submission. KD, a rare, benign, and chronic inflammatory disorder, occurs predominantly in young male adults in Asia. Patients with KD who presents with buccal mass are relatively rare. Immunohistologic analyses suggested that an allergic reaction played an important role in the etiology of KD in this case.

Glomangiopericytoma (GPC) is a rare mesenchymal tumor arising from the nasal cavity or paranasal sinuses. GPC was categorized as a borderline and low-malignant-potential tumor by the World Health Organization in 2005 and accounts for less than 0.5% of all sinonasal tumors. We report a case of GPC in a 74-year-old woman with a history of recurrent epistaxis and nasal obstruction. A reddish tumor was seen in the right nasal cavity. Enhanced computed tomography showed a mass lesion occupying the right nasal cavity. The tumor, which originated from the nasal septum in the olfactory fissure area, was resected with 5-mm mucosal margins by endoscopic sinus surgery. Histologic examination revealed a uniform proliferation of oval-to-short spindle-shaped cells beneath the epithelium. Immunohistologic analysis demonstrated the tumor cells were positive for α-smooth muscle actin, β-catenin and Vimentin, and negative for AE1/AE3, Bcl-2, CD34, CD117, Factor VIIIR Ag, S-100 protein, or STAT6. The percentage of Ki-67-positive cells was approximately 5%. Genetic analysis using next-generation sequencing revealed a missense mutation in the CTNNB1 gene (c.110C > G, p.S37C). While other CTNNB1 mutations have been described in GPC; this is the first report of this specific mutation. The mutation was confirmed using Sanger sequencing.