Polymorphous low grade adenocarcinoma of the palate in a child

Polymorphous Low Grade Adenocarcinoma of the Parotid Gland. Cytological, Histological and Immunohistochemical Features and Review of the Literature

Aim: Polymorphous low grade adenocarcinoma of the salivary glands (PLGA) is a low grade neoplasm that predominantly occurs in the minor salivary glands. In this site is amenable to biopsy and histologic diagnosis. However, experience with cytological findings in these tumors is limited. We describe the cytology of this entity. Experimental design: Touch imprint cytology of a primary parotid PLGA is specified and correlated with histology. Results: Smears were hypercellular showing branching papillae, sheets and clusters of uniform cells with bland nuclei, dispersed chromatin and no nucleoli. The cells had a scant to moderate amount of eosinophilic cytoplasm. They formed tubular structures containing hyaline globules. Conclusions. The cytologic differential diagnosis of PLGA includes adenoid cystic carcinoma, pleomorphic adenoma, and monomorphic adenoma. PLGA should be considered in the differential diagnosis of head and neck tumors, where the cytology suggests on of the above mentioned tumors, even when the clinical findings (involvement of a major salivary gland, lymph node metastasis) is not typical of PLGA.

Not just another paediatric neck lump: metastatic cribriform adenocarcinoma of the palate in an adolescent

Objective:

This paper reports the case of a 13-year-old girl with a 2-year history of left cervical lymph node swelling that was diagnosed as metastatic cribriform adenocarcinoma of the tongue and minor salivary gland.

Case report:

A 13-year-old girl with a left, level II cervical lymph node underwent excisional biopsy after an ultrasound suggested suspicious features. The histology indicated polymorphous low-grade adenocarcinoma, and a primary lesion in the left palate was identified. The patient underwent left maxillectomy, neck dissection and reconstruction. Histological analysis of resection specimens led to a revised diagnosis of cribriform adenocarcinoma of the tongue and minor salivary gland.

Conclusion:

Cribriform adenocarcinoma of the tongue and minor salivary gland has recently been described as a separate entity to polymorphous low-grade adenocarcinoma in light of histological and behavioural differences, including higher rates of metastasis at presentation. This is the first report in the world literature of an adolescent with this entity. It is possible that some previous reports of polymorphous low-grade adenocarcinoma in childhood would have been more accurately described as cribriform adenocarcinoma of the tongue and minor salivary gland.

Low-grade papillary adenocarcinoma of the palate: the significance of distinguishing it from polymorphous low-grade adenocarcinoma

Low-grade papillary adenocarcinoma (LGPA) represents a relatively rare histological variant of polymorphous low-grade adenocarcinoma (PLGA). There has been a debate as to whether LGPA is associated with greater aggressive potential compared to PLGA; this is further obfuscated by the fact that diagnostic criteria for LGPA have not been well-defined. We believe that this is the first report of a patient with LGPA who developed metastases to the femur and scalp. We review the published evidence for classifying LGPA as distinct from PLGA. The weight of published data does support the idea that LGPA is oncologically distinct from LGPA. However, as uniform diagnostic criteria are lacking, we suggest a cut-off value of 10% or greater papillary formation as being necessary to separate LGPA from PLGA.

Polymorphous low-grade adenocarcinoma of minor salivary glands: a study of 17 cases with emphasis on cell differentiation

AIMS

The diagnosis of polymorphous low-grade adenocarcinoma (PLGA) of salivary glands remains difficult for general surgical pathologists. In an effort to understand the morphological heterogeneity of these neoplasms and facilitate their recognition we reviewed the architectural patterns, cell differentiation and immunohistochemical features of 17 case of PLGA.

METHODS AND RESULTS

There were 11 females and six males with a mean age of 58 years. Twelve tumours were located in the palate, two in the posterior third of the tongue, and one each in the upper lip, buccal mucosa and retromolar triangle. Two patients presented with neck metastases. The mean tumour size was 20 mm (range 6-50 mm). The tumour cells were arranged in five architectural patterns: tubules and small duct-like structures; cords and trabeculae; solid nests; cribriform areas and papillae. Twelve (71%) cases were composed of a combination of tubules and small duct-like structures, cords and trabeculae, and solid nests. Cribriform areas with pseudoluminal spaces were seen in six (35%) cases. A focal papillary pattern was evident in three cases and constituted 40% of the tumour in one. Perineural invasion was seen in 13 cases (76%). All cases studied were positive for CAM5.2, 34BE12, vimentin and S100 protein and showed overexpression of bcl-2 protein. Rb protein was present in 13 cases whereas p53 expression was absent in all cases. The average proliferation index (PI) was 7% (range 1-17%). Three patients developed local recurrences with cervical lymph node metastases but no patient died as result of tumour. No morphological features were found to be prognostic for the development of local recurrences or lymph nodes metastases.

CONCLUSIONS

PLGA is a distinctive neoplasm of salivary glands formed by luminal and nonluminal tumour cells with limited patterns of architectural differentiation. The relative proportion of these cells seems to play a significant role in the morphogenesis of these tumours. The overexpression of the bcl-2 protein and the low PI suggest that inhibition of programmed cell death may be involved in the oncogenesis of PLGA.

Terminal duct adenocarcinomas of the parotid gland

The major salivary glands are considered to rarely be the sites of primary terminal duct adenocarcinomas, a neoplasm with a considerable predilection for origin from intraoral minor salivary glands. We present a clinicopathological study of 22 terminal duct adenocarcinomas of the parotid gland, the largest single series to date. A comparison between the parotid neoplasms and over 200 minor salivary gland terminal duct adenocarcinomas indicates there is little difference in biological behaviour and confirms the low-grade quality of the carcinomas, regardless of site of origin.

Salivary terminal duct carcinoma

We report two cases of terminal duct carcinoma of the minor salivary glands. The histological features, biological behaviour, treatment and the long-term management are described.