Low-grade cribriform cystadenocarcinoma of the palatal gland: A case report

Abstract

Abstract. Low-grade cribriform cystadenocarcinoma (LGCCC) is a malignant salivary gland tumor.LGCCC occurs rarely, with the parotid gland being the most commonly afflicted site. Few cases arise in other sites. The present study reports a case of LGCCC that occurred at the palatal gland of the hard palate. A 56-year-old female was referred to Saitama Medical University Hospital (Moroyama, Saitama, Japan) due to an intraoral mass. Since cytological examination and biopsy led to a diagnosis favoring a neoplasm, but with uncertain malignant potential, the tumor was resected with a safe surgical margin. The specimen was thoroughly examined. Microscopically, there was a well-demarcated, unilocular cyst with the lumen lined by tumor cells. The tumor cells were arranged in tubular, cribriform and solid structures in the area of the intracystic mass lesions. Nuclear atypia was inconspicuous, although mitotic figures were observed throughout the tumor. Neither local nor perineural invasion was present. On immunohistochemistry, the tumor cells were diffusely positive for S-100 protein. Myoepithelial markers, calponin and p63, highlighted the cells rimming the cystic mass. The final histopathological diagnosis was of LGCCC. The tumor was completely resected. At 1 year post-resection, the patient exhibited no recurrence or distant metastasis.LGCCC is regarded as clinically indolent. However, there is little literature available to aid with prognosis prediction due to the rarity of LGCCC cases. Thus, greater experience and longer follow-up periods are necessary to find the optimal/curative treatment for patients with LGCCC and to clarify the pathophysiology. IntroductionSalivary gland tumors produce a variety of histological patterns making tumor classification difficult (1).Low-grade cribriform cystadenocarcinoma (LGCCC) is a malignant salivary gland originally reported as a variant of salivary duct carcinoma (2). However, LGCCC differs from typical salivary duct carcinomas with respect to the growth pattern, a lack of evident nuclear atypia, invasiveness to the surrounding tissues, and regional lymph node metastasis (2,3). Thus, the 2005 World Health Organization classification considers this neoplasm to be a variant of cystadenocarcinoma, mainly due to its cystic morphology, since no definite association has been found between salivary duct carcinoma and LGCCC (1). In this classification system, LGCCC is defined by its histological similarity to breast atypical ductal hyperplasia or low-grade ductal carcinoma in situ (1).LGCCC is extremely rare and thus, the incidence rate of LGCCC remains unknown. The parotid gland is the most commonly involved site. Few cases arise at other sites, such as the submandibular gland and palate (2-7). The present study reports a case of LGCCC that occurred at the palatal gland of the hard palate. Written informed consent was obtained from the patient. Case reportA 56-year-old female was referred to Saitama Medical University Hospital (Moroyama, Saitama, Japan) from a local dentist in July 201...

What do we know about the cytological features of pure intraductal carcinomas of the salivary glands?

“…Preoperative fine‐needle aspiration cytology (FNAC) was performed in 13/94 published cases (14%; Table ) . Six patients were male and seven female; IDCs occurred at a mean age of 60 years (32‐79 years).…”

“…Six patients were male and seven female; IDCs occurred at a mean age of 60 years (32‐79 years). Ten cases were localised in the parotid gland (six right, four left), two in the oral cavity and one in the submandibular gland . On histological examination, two parotid IDCs resulted in HG‐IDCs, while the remaining cases were LG‐IDCs .…”

“… Benign lesion (one case; the procedure was performed twice) Tumour of uncertain malignant potential (UMP; seven cases): adenoma with UMP; neoplasm of UMP; primary parotid tumour of UMP; cystic tumour of uncertain malignancy; uncertain whether cystadenocarcinoma or cystadenoma; ductal epithelial proliferative lesion, favouring neoplasm of UMP; atypical cells (possible biphasic neoplasm; benign neoplasm vs low‐grade malignancy) Malignant or suspicious for malignancy (three cases): suspicious for malignancy, favouring low‐grade mucoepidermoid carcinoma; mucoepidermoid carcinoma; malignant cells …”

“…Preoperative FNAC and clinico–pathological correlation are important aids for clinicians and pathologists: FNAC could address to surgery even if an accurate diagnosis is sometimes difficult on cytological material …”

“…can sometimes be difficult in routine practice and accurate grading criteria are not available . The cytological features of IDCs are even less known as few reports have been published and a systematic review is lacking. In addition, pure IDCs and IDCs associated with invasive areas were grouped together in the results of some series, increasing the difficulties in defining the differences between these groups .…”