Cribriform Adenocarcinoma of the Minor Salivary Gland (CAMSG); A Separate and Malignant Entity

Introduction/Objective Cribriform adenocarcinoma of the minor salivary gland (CAMSG) is a recently described salivary gland neoplasm (SGN) that WHO includes under the polymorphous adenocarcinoma (PAC) subheading. CAMSG is reported to occur mostly in the base of the tongue and lingual tonsils. Methods We present a case of CAMSG of buccal mucosa in a 48-year old woman who presented with pain and swelling on the left side of the face that started after tooth extraction. Imaging revealed a large expansile mass (5.8 x 4.3 x 6.1 cm) originating in the left mandibular angle extending into masticator space, maxillary sinus, pterygopalatine fossa, sphenoid, middle cranial fossa, orbit and skull base. Ameloblastoma, primary intraosseous carcinoma, and squamous cell carcinoma were considered. Incisional biopsy revealed a tumor comprised of round to ovoid cells with clear to vesicular nuclei (ground-glass appearance) and occasional mitosis present in irregular solid, cribriform, and microcystic patterns in a hyalinized stroma with the presence of abundant mucin within lobules and stroma. Results Differential diagnosis of secretory carcinoma, hyalinizing clear cell carcinoma, and less likely PAC and mucoepidermoid carcinoma were considered, all inconsistent with the imaging findings. The tumor cells were positive for S100 and negative for CD117, ki67, p63, CD117, and TTF-1. Based on a prominent cribriform pattern, vesicular nuclei, and S-100 expression, a diagnosis of cribriform adenocarcinoma of minor salivary gland origin was rendered. The patient subsequently underwent left partial maxillectomy, left partial mandibulectomy, and resection of the skull base and left neck dissection and was staged as pT4bN0, with negative margins and vascular invasion. The patient underwent radiation therapy and at 6- month follow up was alive and healthy. Clinically and histologically CAMSG overlaps with tumors of both salivary and non-salivary gland origin. Conclusion Recognition of CAMSG as a distinct entity will help in accurate diagnosis and categorization in the WHO classification of SGNs.