Page 44 - AAOMP Meeting 2019

POSTER ABSTRACTS - TUESDAY, JUNE 11, 2019

#39 PRIMARY INTESTINAL-LIKE ADENOCARCINOMA OF THE MINOR SALIVARY
GLANDS: CLINICOPATHOLOGIC AND IMMUNOHISTOCHEMICAL CHARACTERISTICS
OF 2 CASES
Dr. Prokopios Argyris (University of Minnesota), Dr. Rajaram Gopalakrishnan (University of Minnesota), Dr.
Ioannis Koutlas (University of Minnesota)
Objective:Intestinal (colonic)-like adenocarcinoma (ILAC) of salivary gland (SG) origin represents a rare type of salivary
gland tumor with remarkable histopathologic similarity to intestinal-type adenocarcinoma of the sinonasal tract and base of
the tongue with examples reported in the major salivary glands. Immunohistochemically, intestinal-type adenocarcinoma
features strong positivity for CK20, CDX-2 and variable reactivity for CK7, whereas ILAC is CK7(+), CDX-2 and CK20
negative. We report two ILACs affecting intraoral minor SGs.
Findings: Case 1: A 79-year-old male presented with a 1.2-cm submucosal mass of the right posterior buccal mucosa.
Histopathologically, the neoplastic cells were high columnar or cuboidal, characterized by large nuclei with prominent
nucleoli, nuclear pleomorphism and rare mitoses, and formed cystic or cribriform structures. Case 2: A 60-year-old
male presented with a firm, asymptomatic, deep submucosal, nodular lesion of left upper lip, measuring 1.5x1.0 cm.
Microscopic examination revealed a cyst-like space lined by columnar, intestinal-type, epithelium. Mucinous
differentiation was also seen. The neoplastic epithelium demonstrated intraluminal papillary folds. Neoplastic cells featured
cellular pleomorphism with hyperchromatic enlarged nuclei and prominent nucleoli. Both patients did not have history of
colonic adenocarcinoma. By immunohistochemistry, both cases of ILAC were strongly and diffusely positive for CK7, β-
catenin and e-cadherin, focally or rarely positive for CK5/6, CK8/18 (in areas with apocrine features), and negative for
CDX-2, CK20, EMA (MUC-1), S100, calponin, α-SMA, p40, mammaglobin, TTF-1, CD34 and mitochondria.
Interestingly, notwithstanding the absence of nuclear staining, fine and granular CDX-2 paranuclear staining was noticed in
one case. Ki67 nuclear index was 15% for the first case and 30% for the second.
Conclusions: ILAC is a rare type of salivary gland neoplasm exhibiting intestinal features, prominent nuclear
pleomorphism and increased proliferation rates mimicking high-grade intestinal-type adenocarcinomas of the head and
neck. Ancillary CDX-2, CK20 and CK7 immunostains can aid in the diagnosis.

#40 CANALICULAR ADENOMA WITH A UNICYSTIC MORPHOLOGY. REPORT OF A
RARE CASE AND REVIEW OF THE LITERATURE.
Mr. Efstathios Pettas (Dental School, National and Kapodistrian Univeristy of Athens), Dr. Vasileios Ionas
Theofilou (Department of Oral Medicine and Pathology, Dental School, National and Kapodistrian University of
Athens), Dr. Argyrios Daskalopoulos (Department of Oral Medicine and Pathology, Dental School, National and
Kapodistrian University of Athens), Dr. Savvas Titsinides (Department of Oral Medicine and Pathology, Dental
School, National and Kapodistrian University of Athens), Dr. Evangelia P. Piperi (Department of Oral Medicine
and Pathology, Dental School, National and Kapodistrian University of Athens), Dr. Demos Kalyvas (Department
of Oral and Maxillofacial Surgery, Dental School, National and Kapodistrian University of Athens), Prof. Andreas
Lazaris (1st Department of Pathology, School of Medicine, National and Kapodistrian University of Athens),
Prof. Nikolaos G. Nikitakis (Department of Oral Medicine and Pathology, Dental School, National and
Kapodistrian University of Athens)
Objectives: Canalicular adenoma (CA) represents a benign salivary gland tumor, which usually appears as a slowly
growing submucosal nodule with a clear predilection for the upper lip. Histopathologically, it is typically characterized by
monomorphic cuboidal or columnar cells, forming anastomosing or beading structures arranged in a highly vascular, loose
stroma. However, peculiar histopathologic findings and significant overlap with other similar entities, such as basal cell
adenoma (BCA), may be observed complicating the diagnostic process. Herein, we present a rare case of CA with
histopathologic similarities to BCA, exhibiting a solitary cystic morphology. Also, the literature on unicystic CA is
reviewed.
Findings: A 74 year-old female patient with unremarkable medical history presented for evaluation of a painless mass
on the upper lip. The clinical examination revealed a soft, fluctuant submucosal nodule, covered by normal appearing
mucosa. With a provisional diagnosis of benign salivary gland tumor, excisional biopsy was performed. Histopathologic
examination demonstrated an encapsulated solitary cystic formation, lined by monotonous basaloid or cuboidal cells,
arranged in solid or trabecular patterns. Differential diagnosis included BCA or unicystic CA and
immunohistochemical positivity for S-100, CD117 and CK7, as well as negativity for GFAP, SMA and p63, was noted.
A final diagnosis of unicystic CA was rendered, which, to our knowledge represents only the 11 th case reported to this
date.
Conclusions:Cystic morphology has been described in various benign or malignant salivary gland tumors and is associated
with clinical aspects, as well as the biologic behavior of certain neoplasms. Regarding CA, the presence of multiple cystic
spaces has been observed in several cases; however, the occurrence of a true unicystic lesion is considered extremely rare.