Papillary adenocarcinoma of minor salivary gland origin in a child

Historical Evolution of the Polymorphous Adenocarcinoma

The 2017 World Health Organization Classification of Head and Neck Tumors introduced for the first time the diagnostic terminology "cribriform variant of polymorphous adenocarcinoma". This nomenclature attempts to reconciliate the ongoing taxonomical controversy related to cribriform adenocarcinoma of tongue. In order to better understand this classification conundrum, it is imperative for pathologist to comprehend the historical evolution of polymorphous adenocarcinoma formerly known as polymorphous "low grade" adenocarcinoma. This review highlights our understanding of these tumors since their origins.

Newly described salivary gland tumors

This review concentrates on three salivary gland tumors that have been accepted in the recent literature as new neoplastic entities: mammary analog secretory carcinoma (MASC), sclerosing polycystic adenoma (SPA) and cribriform adenocarcinoma of tongue and other minor salivary glands (CAMSGs). MASC is a distinctive low-grade malignant salivary cancer that harbors a characteristic chromosomal translocation, t(12;15) (p13;q25) resulting in an ETV6-NTRK3 fusion. SPA is a rare lesion often mistaken histologically for low-grade salivary carcinoma. Previously thought to be a reactive fibroinflammatory process, but recent evidence of clonality, recurrences in up 30%, and dysplastic foci suggest it may be truly neoplastic. CAMSG is a distinct tumor entity that differs from polymorphous low-grade adenocarcinoma (PLGA) by location (ie, most often arising on the tongue), by prominent nuclear clearing, alterations of the PRKD gene family and clinical behavior with frequent metastases at the time of presentation of the primary tumor. Early metastatic disease seen in most cases of CAMSG associated with indolent behavior makes it a unique neoplasm among all low-grade salivary gland tumors. Salivary glands may give rise to a wide spectrum of different tumors. They are often diagnostically challenging as morphological features often overlap between different entities. Although conventional morphology in combination with immunohistochemical findings still provide the most important clues for diagnosis, recent advances in molecular pathology offer new diagnostic tools in investigating the differential diagnosis, as well as providing potentially valuable prognostic indicators. In the last two decades, several new salivary gland tumor entities have been described, namely MASC, SPA and CAMSGs.

Salivary gland tumor "wishes" to add to the next WHO Tumor Classification: sclerosing polycystic adenosis, mammary analogue secretory carcinoma, cribriform adenocarcinoma of the tongue and other sites, and mucinous variant of myoepithelioma

This review is a continuation of suggested tumor additions to the next WHO Tumor Classification. The author will focus on four salivary gland entities that have recently become accepted in the literature as new neoplastic entities: sclerosing polycystic adenosis, mammary analogue secretory carcinoma, cribriform adenocarcinoma of the tongue and other sites, and mucinous variant of myoepithelioma.

Cribriform adenocarcinoma of minor salivary gland: a report of two cases with an emphasis on cytology

Cribriform adenocarcinoma of minor salivary gland (CAMSG) is a recently characterized low grade salivary gland malignancy that most commonly presents as a mass in the base of the tongue, frequently with regional lymph node metastasis. Given its relative rarity and overlapping cytomorphology, CAMSG may be confused with polymorphous low grade adenocarcinoma (PLGA) in minor salivary gland sites and papillary thyroid carcinoma (PTC) in cervical metastasis, in both fine-needle aspiration and excisional specimens. As there are no cytology reports in the literature, we present two new cases of CAMSG and describe the aspiration cytology of the tumor taken from bench top aspirates, compare it with the histomorphology, and discuss the features that may help one avoid misdiagnosis of PTC in the setting of cervical lymph node metastasis. We found that like PTC, aspirates of CAMSG contain polymorphic fragments of epithelial cells arranged in monolayer sheets, papillary fronds and tips, and occasional cribriform configurations, and metachromatic stromal fragments, which may be misinterpreted as colloid. A background of myxoid/mucoid material also reminiscent of colloid was prominent. Differentiation from PLGA is more difficult based strictly on cytology. A review of the most current literature in relation to the molecular and immunohistochemical profiles, therapeutic options, and prognosis is also presented. It is critical for pathologists and clinicians to be aware of this tumor when presented with patients having a cervical lymph node mass in the absence of a primary tumor.

Adenocarcinoma of the anterior tongue: a case report

Adenocarcinoma of the minor salivary gland more commonly involves the palate and base of tongue but rarely presents in the anterior tongue. We report a rare case of adenocarcinoma of the minor salivary gland located in the anterior togue of a 74-year-old man. Furthermore, we discuss the histopathological features of this neoplasm, the treatment plan, and a literature review of the current standard of care.

Cribriform adenocarcinoma of the tongue and minor salivary glands: a review

Cribriform adenocarcinoma of the tongue and minor salivary glands (CATMSG) is a tumor occurring mostly, but not exclusively, in the base of the tongue. Other locations are minor salivary glands of the oral cavity. Histopathologically, CATMSG resembles papillary carcinoma of the thyroid gland. It usually reveals a solid growth devoid of colloid, and eosinophilic material present in follicular areas is rather pale in contrast to metastatic foci seen in papillary thyroid carcinoma that shows typical deeply eosinophilic colloid with "moth-eaten peripheries" and cystic configuration. In addition, giant multinucleated cells are not observed in CATMSG and psammoma bodies are found only exceptionally. Unlike papillary thyroid carcinoma, CATMSG is composed of hybrid secretory-myoepithelial cells. Most importantly, CATMSG is consistently negative with both thyroglobulin and TTF-1. CATMSG is a distinct tumor entity that also differs from polymorphous low-grade adenocarcinoma by location, cytology, histological architecture, and behavior, with frequent metastases at the time of presentation. Paradoxically, early metastatic disease seen in most cases of CATMSG is associated with an indolent behavior. It makes CATMSG a unique neoplasm among all low-grade salivary gland tumors.

Cribriform adenocarcinoma of minor salivary glands may express galectin-3, cytokeratin 19, and HBME-1 and contains polymorphisms of RET and H-RAS proto-oncogenes

The aim of the study was to further elucidate the immunohistochemical and genetic characteristics of cribriform adenocarcinoma of minor salivary glands (CAMSG). The study comprised five CAMSG from two males and three females, aged 21-72 years. Four tumors were localized at the base of tongue and one in the floor of mouth. At the time of diagnosis, four tumors had metastasised to regional lymph nodes. After tumor resection, two patients were treated by radiotherapy and one by chemoradiotherapy. During the follow-up (median 14 months), two patients developed lymph node metastasis. Microscopically, all tumors showed cribriform, papillary, follicular, and microcystic growth patterns. The tumor cells displayed vesicular nuclei with intranuclear grooves. Immunohistochemically, all tumors showed expression of cytokeratin (CK) 7, CK8, CK18, vimentin, smooth muscle actin, calponin, S-100 protein, and p16 protein. In addition, we observed expression of galectin-3, CK19, and HBME-1, but not of thyroglobulin and TTF-1. No mutations of RET, BRAF, K-RAS, H-RAS, and N-RAS proto-oncogenes were detected. However, in RET proto-oncogene, we found polymorphisms Gly691Ser (exon 11) and Ser904Ser (exon 15) in one case, p.Leu769Leu (exon 13) in one case, and variant p.IVS14-24 G/A of intron 14 in two cases, and in H-RAS proto-oncogene we found polymorphism 81 T-C (exon 1) in three cases. Thyroglobulin and TTF-1 are the only useful markers in the differential diagnosis between CAMSG and papillary thyroid carcinoma as both tumors may express galectin-3, CK19, and HBME-1. The RET, H-RAS, and N-RAS proto-oncoogenes are not mutated in CAMSG.

Cribriform adenocarcinoma of the tongue: a hitherto unrecognized type of adenocarcinoma characteristically occurring in the tongue

AIMS

We report a review of our institutional and consultation files in order to select cases of hitherto unrecognized type of adenocarcinoma occurring in the tongue.

MATERIALS AND RESULTS

Eight cases of a characteristic adenocarcinoma of the tongue resembled solid and follicular variants of the papillary carcinoma of the thyroid. All the tumours were unencapsulated and were divided by fibrous septa into lobules. Major parts of the lesions were composed of areas with solid and microcystic growth patterns. The most striking cytological feature was that the tumour nuclei were pale-staining with a 'ground glass' quality, and they often appeared to overlap. Immunohistochemically, the tumours expressed cytokeratin and S100 protein and, focally, actin; thyroglobulin was negative. Ultrastructurally the cells had clefted nuclei, and the cytoplasm contained a few mitochondria, lysosomes and Golgi apparatus. Many tumour cells had combined features of both myoepithelial and secretory differentiation-well formed microvilli on their apical borders and bundles of microfilaments. At first presentation, all eight patients had metastases in the regional neck lymph nodes, but all are alive 2-6 years after the initial excision and irradiation.

CONCLUSION

We describe a distinctive type of adenocarcinoma of the tongue, for which we propose the name cribriform adenocarcinoma of the tongue (CAT). CAT usually presents with metastases in the neck lymph nodes at the time of presentation. We hypothesize that the tumour might arise from the thyroglossal duct anlage.

Salivary gland cystadenocarcinomas. A clinicopathologic study of 57 cases

Current classification schemes for salivary gland neoplasms categorize cystadenocarcinomas on the basis of a recurring histomorphologic pattern of cystic, and often, papillary growth without features of other specific types of salivary gland tumors. To ascertain the clinicomorphologic spectrum and biologic behavior of this tumor, the clinicopathologic features of 57 cystadenocarcinomas from the files of the Armed Forces Institute of Pathology were studied. Excluding five Veterans Administration military cases, men and women were equally affected. Patients ranged in age from 20 to 86 years (mean, 58.8; median, 64), and patients aged over 50 years accounted for 71% of cases. Thirty-seven tumors (65%) occurred in major salivary glands, 35 in the parotid, and two in the sublingual glands. The 20 minor salivary gland tumors (35%) involved, in descending order, the lips, buccal mucosa, palate, tongue, retromolar area, and floor of mouth. Grossly, the lesions were cystic or multicystic masses that ranged in size from 0.4 to 6.0 cm. Microscopically, all tumors demonstrated an invasive, cystic growth pattern, and 75% had a conspicuous papillary component. The predominant cell type varied among tumors and included small cuboidal cells (35 cases), large cuboidal cells (nine cases), and tall columnar cells (seven cases). Six cases exhibited an admixture of cell types. Ruptured cysts with hemorrhage and granulation tissue were common. All 40 patients with follow-up data were either alive or had died of other causes and were free of tumor a mean interval of 59 months after their initial surgery. Three tumors recurred locally (mean interval, 76 months). Three tumors were metastatic to regional lymph nodes at the time of diagnosis, and one patient developed a regional lymph node metastasis after 55 months. Salivary gland cystadenocarcinomas represent a distinct group of malignancies that have an indolent biologic behavior.

Low-grade papillary adenocarcinoma of minor salivary glands. Case report and literature review

Low-grade papillary adenocarcinoma of minor salivary glands is rare and tends to occur in the palate. This tumor has distinct but rather deceptive histomorphologic features, which may cause erroneous diagnosis. An extensive English-language literature review revealed reports of 22 well-documented low-grade papillary adenocarcinomas. Six of these tumors (27%) recurred locally between 12 months and 19 years after initial treatment. Low-grade papillary adenocarcinoma appears to have more aggressive biologic behavior compared with other low-grade adenocarcinomas in this region. Four of the reported cases (17%) had cervical lymph node metastases at the time of presentation. We report an additional case and discuss the literature.

Mucus-producing adenopapillary carcinoma of minor salivary gland origin with signet ring cells and intracytoplasmic lumina. A light and electron microscopic study

A histological and subcellular study of a mucus-producing adenopapillary carcinoma of a minor salivary gland is presented. The tumor was located on the buccal mucosa of a 36-year-old white man. Microscopic examination showed that the tumor was an invasive papillary growth with numerous signet-ring cells and mucous production. When viewed under the electron microscope, the tumor exhibited clusters of cells showing intracellular lumina and finely dispersed chromatin.