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Mucoepidermoid carcinoma (MEC) is the most common malignant tumour of the salivary gland, primarily involving the parotid gland. Here, the cases of two patients, aged 47 and 67 years, respectively, who underwent surgery for pathologically confirmed Warthin-like MEC of the parotid gland between January 2019 and December 2019 in Anyang Tumour Hospital, are described. In each case, the tumour consisted of epithelial and lymphoid cell components, covered with two or more layers of epithelium, with visible scattered mucous cells, and lymphoid stroma with a large number of lymphocytes and germinal centres formed. Most importantly, the tumours lacked the well-organized, bilayered oncocytic epithelial structure that is characteristic of Warthin’s tumour. Mastermind like transcriptional coactivator 2 ( MAML2) gene rearrangements were identified in the tumour cells using break-apart fluorescence in situ hybridization (FISH) probes, confirming the diagnosis of Warthin-like MEC. Post-operatively, patients have remained disease free for 31 and 27 months, respectively. Warthin-like MEC of the parotid gland is rare and is often misdiagnosed as metaplastic Warthin’s tumour. Diagnosis depends mainly on the unique clinicopathologic features together with FISH analyses.

This current case report presents the detailed clinicopathological analysis of three patients with papillary thyroid carcinoma, each of which presented with the ‘snowstorm appearance’ on ultrasonography. Ultrasonography of this tumour typically shows a diffusely enlarged thyroid with hypoechoic and heterogeneous internal echoes, and diffusely scattered microcalcifications, which form the ‘snowstorm appearance’. Microscopically, case 1 had a large number of psammoma bodies, infiltration of lymphocytes, formation of lymphatic follicles and extensive squamous metaplasia, leading to the diagnosis of a diffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC). Case 2 was diagnosed with follicular papillary thyroid carcinoma. Their tumour had numerous calcifications in the stroma and follicles. Case 3 was diagnosed with a multifocal papillary thyroid carcinoma in the background of Hashimoto's thyroiditis. Their tumour showed calcification in the stroma and follicles, together with cervical lymph node metastasis. DSVPTC is a rare variant of thyroid papillary carcinoma. It has the ‘snowstorm appearance’ on ultrasound, but this can also be found in follicular papillary carcinoma and multifocal thyroid papillary carcinoma. Papillary thyroid carcinoma with the ‘snowstorm appearance’ has a large number of peripheral lymph nodes metastases, thus requiring radical surgery and postoperative adjuvant therapy.