DNA flow cytometry of reclassified subtypes of malignant salivary gland tumors

[DNA ploidy and proliferative activity in salivary gland tumours]

DNA ploidy and S-Phase fraction (SPF) of 279 salivary gland tumours were analysed using high-resolution DNA flow cytometry. All 229 benign neoplasms were diploid while 12 of 50 malignant tumours showed cell populations with aneuploid DNA content. The SPF values of diploid malignancies were significantly higher if compared with pleomorphic adenomas but did not differ from that of the zystadenolymphoma (Warthin tumour) group. While aneuploidy represents a distinct indicator of malignancy SPF values are of minor relevance for dignity assessment in salivary gland tumours.

Amplificación del gen de la ciclina d1 en los carcinomas adenoides quísticos de glándulas salivares menores

OBJECTIVE

Adenoid cystic carcinoma (ACC) is a tumour of epithelial origin that represents the most common malignant neoplasm of the minor salivary glands. However, little is known about the genes involved in the development and progression of this tumour. Cyclin D1 gene (CCND1) plays a key role in the control of the cell cycle, and its amplification is described in numerous cancers. The aim of this study is to determine the amplification of the CCND1 gene in the ACC of the minor salivary glands.

MATERIALS AND METHODS

A retrospective study was performed on 12 patients with ACC of the head and neck. The amplification of the CCND1 was determined using multiple PCR.

RESULTS

Amplification of the CCND1 was found in 4 patients (33.3%). No correlation was found between CCND1 amplification and clinicopathological parameters, although disease-free survival was diminished in patients with amplification.

DISCUSSION/CONCLUSIONS

Our study demonstrates for the first time the amplification of the CCND1 gene in ACC. We have found an amplification rate similar to others neoplasms. CCND1 amplification seems to be associated with a poorer prognosis in these tumours, although this needs to be confirmed in larger studies.

Major salivary gland cancer

Major salivary gland cancers are rare, with many histologic types and subtypes. The tumor stage at presentation will dictate the need for imaging,FNA, and facial nerve monitoring. Immunohistochemistry has enhanced diagnosis. In addition, precise attention to surgical landmarks and technique will reduce complications. Tumor stage, histologic type, tumor grade,surgical margin, facial nerve dysfunction, perineural involvement, extra-parenchymal spread, and nodal metastasis are factors influencing the indication for neck dissection, postoperative radiation therapy, and survival rate.

Parotid gland mucoepidermoid carcinoma in a 4-year-old child

Salivary gland tumors account for less than 5% of the head and neck neoplasms. Among them, mucoepidermoid carcinoma is the most common malignant salivary gland tumor. About 45% of mucoepidermoid carcinomas occur in the parotid gland, and appear around the fifth decade of life, being unusual in children under 10 years. We report a case of a parotid mass arising in a 4-year-old female, who had no lateral adenopathy. After histological examination, the diagnosis was of a low-grade mucoepidermoid carcinoma of the parotid gland. Three years after surgery no recurrence was observed. As a conclusion, although rare, the presence of a parotid mass with progressive growth in children could correspond to a neoplasm.

Pleomorphic adenoma of the salivary glands: prospective clinicopathologic and flow cytometric study

BACKGROUND

Primary surgery is the appropriate treatment for most pleomorphic adenomas of the salivary glands. However, no reliable criteria have been established to predict tumors with aggressive features.

METHODS

In 44 patients treated for salivary pleomorphic adenoma, clinicopathologic features and flow cytometric findings were recorded. S-phase fractions were classified as low (0%-1%), intermediate (1.1%-5%), and high (>5%). The relationship between clinicopathologic parameters and flow cytometric DNA analysis was assessed with the Pearson's correlation coefficient.

RESULTS

The mean tumor size was 24.4 mm. Microscopically, myxoid structures predominated in 61.4% of cases. Only five specimens showed high S-phase fractions. All samples were DNA diploid (mean coefficient of variation 3.2%). S-phase fraction and tumor size correlated significantly (r = 0.73, P = 0.003). Two patients with recurrent tumors had high S-phase fractions both on the first resected specimens and at the time of the second operation.

CONCLUSIONS

The S-phase fraction may be a valuable predictor of aggressive behavior in salivary pleomorphic adenomas. High S-phase fractions were associated with higher tumor size and a greater tendency to recur.

DNA analysis of malignant salivary gland carcinomas: comparison of different tissue preparations and measuring techniques

This study correlates static and flow-cytometric analysis on paraffin-embedded and fresh material of salivary gland carcinomas. Nuclear suspensions for DNA analysis were prepared from paraffin-embedded and fresh material. Comparison of the results of static and flow cytometry on paraffin-embedded material revealed no significant correlation between DNA ploidy and S-phase value. The coefficients of variation were significantly lower for static than for flow cytometry (p < 0.05). Flow-cytometric analysis on fresh and paraffin-embedded material correlated well concerning DNA ploidy, but not for the S-phase. The coefficients of variation were significantly lower for the fresh than for the paraffin-embedded material (p < 0.001). Cytometric analysis on paraffin-embedded material of malignant salivary gland carcinomas should be critically evaluated. There is a need for flow-cytometric investigations on fresh material to clarify further the prognostic value of this method.

Parotid gland lesions: diagnosis of malignancy with MRI and flow cytometric DNA analysis and cytology in fine-needle aspiration biopsy

BACKGROUND

The purpose of this study was to assess the capability of magnetic resonance imaging (MRI) and cytology and flow cytometric (FCM) deoxyribonucleic acid (DNA) analysis in fine-needle aspiration biopsy (FNAB)-derived materials for diagnosing malignancy of the parotid lesions and the efficacy of FCM analysis in FNAB.

METHODS

Magnetic resonance imaging findings and FCM results (ploidy and S + G2 + M phases [S + G2M] fraction) and cytology in FNAB-derived materials in 26 patients with 26 parotid lesions (12 benign lesions, 14 malignancies) were assessed for predicting malignancy. Flow cytometric results in aspirates were compared with those in surgically resected tissues.

RESULTS

When a single predictor was used, cytology (92% accuracy) was most accurate for malignancy, followed by ill-defined margin (88% accuracy) and aneuploidy (88% accuracy). The combination of FCM and cytology raised the rate of sufficient materials from 92% to 100% and accuracy from 92% to 96% compared with cytology alone. The same highest accuracy (96%) was obtained with the combination of the ill-defined margin or other findings such as cytology, aneuploidy, or a high (S + G2M) fraction (6% <). Deoxyribonucleic acid ploidy in the FNAB showed full agreement with that in the surgical specimens. Receiver operating characteristic curves showed that the diagnosis of malignancy with (S + G2M) fraction in FNAB was superior to that in surgical specimens, but no significant difference was noted.

CONCLUSIONS

A combination of MRI findings, cytology, and FCM results is optimal for diagnosing malignancies of the parotid lesions, and FNAB may replace the surgical specimens in FCM analysis.

Role of DNA measurements of head and neck tumors

The measurement of DNA ploidy has been used as a tool to try to determine the prognosis of many neoplasms. DNA ploidy can be determined by flow cytometry or image analysis of a tumor. In squamous carcinomas of the head and neck, a poorer prognosis has been associated with nondiploid tumors. Similar results have been obtained from studies of salivary gland neoplasms. The role of DNA ploidy as a provider of independent information has yet to be determined. With rarer head and neck tumors, measurement of tumor ploidy has yet to be established as a valuable adjunct to routine light microscopic study.

Observer variability in histological malignancy grading of adenoid cystic carcinomas

The value of malignancy grading of adenoid cystic carcinomas (ACC) is controversial. Some studies have shown that tumours with a solid growth component have a rapid fatal course, compared to tumours without a solid growth component, in which recurrences develop even many years after initial treatment. Other studies have failed to correlate growth patterns with clinical course. No universally accepted grading system exists and no reproducibility studies of the existing grading systems have been performed. The aim of this study was to examine the reproducibility of grading based on semi-quantitative assessment of the solid growth pattern in ACC. Two different grading systems were assessed by 3 observers on a material of 59 ACC. Interobserver agreement was evaluated using the kappa statistic. The reproducibility of grading was poor, except for the category "solid component constituting 50% or more of the tumour" (kappa = 0.52). It is concluded that quantitative methods are necessary if grading is to be used in prognostic evaluation of ACC. The rarity of the tumours, however, combined with difficulties in diagnosis will impede such investigations unless multicentre studies are undertaken.

Prognostic significance of biomarkers (c-erbB-2, p53, proliferating cell nuclear antigen, and DNA content) in salivary duct carcinoma

Salivary duct carcinoma (SDC), a rare neoplasm of the major salivary glands, is a high-grade carcinoma with a predilection for elderly men. The authors investigated the prognostic role of p53, c-erbB2, proliferating cell nuclear antigen (PCNA), and DNA flow cytometry in a pathobiological evaluation of a cohort of 30 patients with these neoplasms. The patient group comprised 24 men and 6 women, with ages ranging from 22 to 87 years (mean = 61 years). Twenty-eight tumors were located in the parotid gland and two in the submandibular gland. Tumor size ranged from 1.0 to 8.0 cm (mean = 3.48 cm). Regional metastases were found in 73.3% (22 patients), systemic metastases in 43.3% (13 patients), and recurrences in 8 (26.6%) patients. DNA aneuploidy was found in 18 tumors (58.0%) and DNA diploidy in 12 (42%), with proliferative fractions ranging from 8.60% to 15.5 (mean = 10.6%). p53 protein nuclear immunostaining was positive in 56.6% and c-erbB2 overexpression was observed in 63% of the tumors. PCNA positivity ranged from 16.5% to 91.0%, with a mean of 49.5%. p53 immunopositivity, DNA aneuploidy, high growth, and proliferative fractions by PCNA and flow cytometry did not correlate with patient outcome. These results indicate that tumor size (P = .05), distant metastasis (P = .006), and C-erbB2 amplification (P = .04) are independent prognostic parameters in patients with salivary duct carcinoma.

Myoepithelial carcinoma arising in a benign myoepithelioma: immunohistochemical, ultrastructural, and flow-cytometrical study

A case of myoepithelial carcinoma arising in a benign myoepithelioma of the minor salivary gland in a 71-year-old patient is reported. The tumor presented initially on the palate and had been diagnosed as "benign lesion" 40 years before. It recurred 22, 36, and 40 years after initial presentation, and a similar histopathological diagnosis was rendered. One year after the last recurrence, the tumor recurred showing typical changes of malignant transformation, and the diagnosis was malignant myoepithelioma. The light microscopy and ultrastructural features of the initial tumor were typical of plasmocytoid myoepithelioma. There were abundant round cells and rare spindle cells with uniform dispersed filaments, sometimes arranged in parallel streams without evidence of dense bodies. These cells showed micropinocytotic vesicles along the cell membrane with poorly developed intercellular junctions and were surrounded by a basal membrane. The malignant counterpart showed fewer plasmocytoid cells and a rather epithelial pattern with marked nuclear pleomorphism and formation of small, or rarely large, glandular lumina. The immunohistochemical features were similar for the benign and malignant tumors, with positivity for S-100 protein, vimentin, cytokeratins, and CAM 5.2, and were negative for GFAP, muscle-specific actin, CEA, and desmin. Flow cytometry showed a change in the DNA content profile. The benign myoepithelioma had a diploid DNA content with a low S-phase fraction of 3.9% and proliferative index of 9.1%, while the myoepithelial carcinoma had an evident aneuploid DNA stem line and an increased S-phase fraction of 8.3% with a proliferative index of 18.1%.