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

Abstract

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.

Giant cribriform adenocarcinoma of the tongue showing PRKD3 rearrangement

“…Therefore, thyroglossal duct anlage was considered as a potential source of origin of this malignancy [1]. Since then, more that 40 well-documented cases have been described in the English literature [3,4,5,6,7,8,14,15,16]. In Poland the first case of this tumor was described by Borowski-Borowy et al in 2011 [5].…”

“…Only two patients received adjuvant chemotherapy with cisplatin [3,8]. The treatment of CAMSG should aim toward complete surgical excision, supplemented by lymphadenectomy if dissemination is evident.…”

“…Differential diagnosis of CAMSG includes papillary thyroid carcinoma (PTC, either metastatic or developing within the lingual thyroid), polymorphous low grade adenocarcinoma (PLGA) and adenoid cystic carcinoma [1,3,4,6,9].…”

“…In the 2005 World Health Organization Classification of Tumors the entity was classified as a possible variant of polymorphous lowgrade adenocarcinoma (PLGA) [2]. Since then, more than 40 cases have been described in the English literature [1,3,4,5,6,7,8]. Although originally designated as CAT and considered to be restricted to the tongue, it was later shown to arise from the minor salivary glands of the soft palate, buccal mucosa, area of the palatine tonsils, upper lip and even epiglottis [4].…”

Expression of Human Tissue Kallikreins (KLKs) in Polymorphous Low Grade Adenocarcinoma (PLGA)

“…Michal et al postulate that if CATMSG was considered a separate entity, the rate of PLGA metastasis to regional lymph nodes would be significantly lower [33]. Distant metastases have not been reported to date [38]. Although more patient lymph node metastases at the time of presentation, the tumour remains indolent overall, with a favourable prognosis [33].…”