Extracapsular invasion: A potential prognostic marker for Carcinoma ex‐pleomorphic adenoma of the salivary glands? A Systematic Review

Development and Evaluation of a Convolutional Neural Network for Microscopic Diagnosis Between Pleomorphic Adenoma and Carcinoma Ex-Pleomorphic Adenoma

AIMS

To develop a model capable of distinguishing carcinoma ex-pleomorphic adenoma from pleomorphic adenoma using a convolutional neural network architecture.

METHODS AND RESULTS

A cohort of 83 Brazilian patients, divided into carcinoma ex-pleomorphic adenoma (n = 42) and pleomorphic adenoma (n = 41), was used for training a convolutional neural network. The whole-slide images were annotated and fragmented into 743 869 (carcinoma ex-pleomorphic adenomas) and 211 714 (pleomorphic adenomas) patches, measuring 224 × 224 pixels. Training (80%), validation (10%), and test (10%) subsets were established. The Residual Neural Network (ResNet)-50 was chosen for its recognition and classification capabilities. The training and validation graphs, and parameters derived from the confusion matrix, were evaluated. The loss curve recorded 0.63, and the accuracy reached 0.93. Evaluated parameters included specificity (0.88), sensitivity (0.94), precision (0.96), F1 score (0.95), and area under the curve (0.97).

CONCLUSIONS

The study underscores the potential of ResNet-50 in the microscopic diagnosis of carcinoma ex-pleomorphic adenoma. The developed model demonstrated strong learning potential, but exhibited partial limitations in generalization, as indicated by the validation curve. In summary, the study established a promising baseline despite limitations in model generalization. This indicates the need to refine methodologies, investigate new models, incorporate larger datasets, and encourage inter-institutional collaboration for comprehensive studies in salivary gland tumors.

Distinct copy number signatures between residual benign and transformed areas of carcinoma ex pleomorphic adenoma

The mechanisms involved with the pathogenesis of carcinoma ex pleomorphic adenoma (CXPA) seem to be associated with the accumulation of molecular alterations in the pleomorphic adenoma (PA). In this sense, using array-based comparative genomic hybridization (aCGH) a rare series of 27 cases of CXPA and 14 residual PA (rPA) adjacent to the transformation area, we investigated the profile of the copy number alterations (CNAs) comparing benign residual and transformed areas. The main findings were correlated with the histopathological classification by histologic subtype and degree of invasion. The distribution of losses (p = 0.187) and amplifications (p = 0.172) was not statistically different between rPA and CXPA. The number of gains was increased in the transformed areas compared to the benign residual areas (p = 0.005). PLAG1 gain was maintained along the malignant transformation, as it was observed in both residual PA and CXPA samples, likely being an earlier event during transformation. The amplification of GRB7 and ERBB2 may also be an initial step in the malignant transformation of PA to CXPA (salivary duct carcinoma subtype). Furthermore, the amplification of HMGA2 and RPSAP52 were the most prevalent alterations among the studied samples. It was noteworthy that amplified genes in the transformed areas of the tumors were enriched for biological processes related to immune signaling. In conclusion, our results underscored for the first-time crucial CNAs in CXPA, some of them shared with the residual benign area adjacent to the transformation site. These CNAs included PLAG1 gain, as well as amplification of GRB7, ERBB2, HMGA2, and RPSAP52.

MicroRNA copy number alterations in the malignant transformation of pleomorphic adenoma to carcinoma ex pleomorphic adenoma

OBJECTIVE

This study used array comparative genomic hybridization to assess copy number alterations (CNAs) involving miRNA genes in pleomorphic adenoma (PA), recurrent pleomorphic adenoma (RPA), residual PA, and carcinoma ex pleomorphic adenoma (CXPA).

MATERIALS AND METHODS

We analyzed 13 PA, 4 RPA, 29 CXPA, and 14 residual PA using Nexus Copy Number Discovery software. The miRNAs genes affected by CNAs were evaluated based on their expression patterns and subjected to pathway enrichment analysis.

RESULTS

Across the groups, we found 216 CNAs affecting 2261 miRNA genes, with 117 in PA, 59 in RPA, 846 in residual PA, and 2555 in CXPA. The chromosome 8 showed higher involvement in altered miRNAs in PAs and CXPA patients. Six miRNA genes were shared among all groups. Additionally, miR-21, miR-455-3p, miR-140, miR-320a, miR-383, miR-598, and miR-486 were prominent CNAs found and is implicated in carcinogenesis of several malignant tumors. These miRNAs regulate critical signaling pathways such as aerobic glycolysis, fatty acid biosynthesis, and cancer-related pathways.

CONCLUSION

This study was the first to explore CNAs in miRNA-encoding genes in the PA-CXPA sequence. The findings suggest the involvement of numerous miRNA genes in CXPA development and progression by regulating oncogenic signaling pathways.

Pleomorphic Adenoma of a Minor Salivary Gland of the Hard Palate: A Case Report

Pleomorphic adenoma affects mostly the parotid gland (85%), submandibular glands (5%), and the minor salivary glands (5%). They are usually referred to as benign mixed tumors because they are composed of both epithelial cells, which are cells from the body's surface, and myoepithelial cells, present inside glands to aid in secretion. An 88-year-old male who had an ulcer for 10 days and a three to four-month-old swelling on his palate arrived in the OPD. On examination, at the intersection of the hard and soft palates, there is a single, well-delineated, nodular exophytic development of small salivary glands left to the median half (most of the pleomorphic adenomas are unilateral). For further and confirmatory diagnosis, fine needle aspiration cytology, immunohistochemistry tests, and radiodiagnosis, i.e., X-rays, were performed which revealed periapical abscess and swelling on palate unassociated with pus discharge. Surgical removal of the swelling and extraction of the root stump was done. The patient was asked to stop smoking strictly. Post-operatively, the patient was given suitable medications.

Carcinoma ex-pleomorphic adenoma of mandible: A case report and review of literature

Introduction and importance

The most common benign neoplasm of major and minor salivary glands is pleomorphic adenoma (PA). Around 80 % of all parotid neoplasms are pleomorphic adenomas, while 44–68 % and 38–43 % tumors were pleomorphic adenomas of submandibular and minor salivary gland tumors. PA has been reported in a variety of anatomic locations including true intraosseous mandibular tumor, external ear canal, TMJ region, lacrimal gland, epiglottis, larynx and nasopharynx, breast, lung, esophagus, sinonasal and skull base and trachea.

Pleomorphic adenoma has a tendency to transform into a number of malignancies; carcinoma ex-pleomorphic adenoma, carcinosarcoma or metastasizing pleomorphic adenoma. Pleomorphic adenomas most commonly transform into carcinoma ex-pleomorphic adenoma (CEPA).

Case presentation

A 30-year-old male presented with the primary complaint of a long-standing swelling at his right mandibular region for past 18 months. On intra oral examination, there was a non-healing alveolar socket of right lower 3rd molar tooth while rest of the dentition and mucosal surfaces were normal. On extra oral examination, mouth opening was adequate with intact lower border of the mandible and no palpable lymph nodes in the neck. Initial biopsy of lesion showed pleomorphic adenoma, but later the lesion came out to be carcinoma ex-pleomorphic adenoma, for which he underwent segmental mandibulectomy and free fibular flap.

Clinical discussion

The prevalence of CEPA transformation from pleomorphic adenoma is 1.5 % within the first 5 years of diagnosis, going up to 10 % after 15 years. The true rate of malignant transformation in recurrent pleomorphic adenoma is reported to be 3.3 %. We report a case of an intra-osseous carcinoma ex pleomorphic adenoma (CEPA) of the mandible. It is thought that ectopic entrapment of salivary tissue or developmentally included embryonic remnants of submandibular glands within recesses or lacunae of the mandibular bone could explain the intraosseous origin of a salivary gland tumor in the mandible. Since carcinoma ex pleomorphic adenoma (CEPA) arises from primary or recurrent pleomorphic adenoma, therefore it poses a diagnostic challenge for histopathologists. The radiographic picture of primary tumor/recurrence can mimic odontogenic cyst/tumor; therefore, a sinister disease process should always be kept in mind. In the post operative period, regular follow up is required to treat any recurrence. The recurrence rate for such disease has not been documented.

Conclusion

Intra osseous CEPA is a very rare tumor. Intra bony tumors which rapidly increase in size have signs and symptoms of nerve involvement and cause bony destruction should have a high suspicion of index of malignancy. Therefore, biopsy must be correlated with clinical and radiological features. Regular follow up is necessary to detect any recurrence promptly.

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Carcinoma expleomorphic adenoma is a salivary gland tumor that can rarely occur in unique sites like mandible.

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Pleomorphic adenoma can co-exist with carcinoma expleomorphic adenoma which may give different biopsy results.

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Clinical and radiological correlation with tissue diagnosis is important.

Carcinoma ex pleomorphic adenoma of major salivary glands: CT and MR imaging findings

OBJECTIVES

To describe the CT and MR imaging characteristics of primary carcinoma ex pleomorphic adenoma (Ca-ex-PA) in major salivary glands and present more information for recognizing this malignancy.

METHODS

212 patients with primary Ca-ex-PA in major salivary glands (169 in the parotid gland, 36 in the submandibular gland, 7 in the sublingual gland) underwent CT and MR imaging (plain and contrast-enhanced scans) prior to surgical management and histopathological examination. The CT and MR imaging findings of this condition were retrospectively reviewed and correlated with their pathological types: non-invasive carcinoma (Type I, 37 cases), minimally invasive carcinoma (Type II, 18 cases), and widely invasive carcinoma (TypeIII, 157 cases). The binary logistic regression analysis was used to analyze the independent influencing factors of morphology and boundary for differentiating between Type I/II and Type III of Ca-ex-PA, and the sensitivity, specificity and positive predictive value were calculated. Differences in apparent diffusion coefficient (ADC) values between Type I/II and Type III of Ca-ex-PA were calculated by independent sample t-tests.

RESULTS

On CT and MR imaging, there were 190/212 cases (89.6%) identified as lobular, 203/212 cases (95.8%) with enhancement, and 173/212 cases (81.6%) with inhomogeneous after contrast administration.Calcification within the mass was shown in 76 of 192 cases (39.6%) on plain CT examination. Of 55 neoplasms with Type I and II, 38 (69.1%) were presented as round or oval and 42 (76.4%) as well-defined margins. Of 157 neoplasms with Type III, 103 (65.6%) were presented as irregular form and 110 (70.1%) as uneven margins or with partial uneven margins.The sensitivity, specificity and positive predictive value for distinguishing Type I/II and Type III tumors according to the morphology and boundary were 78.34%, 63.64% and 86.01%, respectively. The mean ADC value of Ca-ex-PA (22 cases) in major salivary glands was about 0.93 × 10^-3 mm² s^-1, and there was no significant difference in mean ADC value between Type I/II and Type III of this neoplasm. Cervical lymph node metastasis and distance metastasis were found in 67 patients (31.6%, Type III) and 32 patients (15.1%, Type I in 1; Type II in 1; and Type III in 30), respectively.

CONCLUSIONS

Most Ca-ex-PA is characterized by an irregular, lobular, and inhomogeneous enhanced neoplasm with uneven margin or partial uneven margin on CT and MR imaging, which is frequently corresponding with Type III. And a round or oval mass with well-defined margin usually correlates with Type I and II. Morphology and boundary are important basis for distinguishing Type I/II and Type III tumors. Calcification within the neoplasm shown on CT may be regarded as a specific sign for indicating this malignancy. Low ADC value is an important manifestation of this neoplasm.Ca-ex-PA with Type III is more likely to have cervical lymph node metastasis and distant metastasis.

Outcomes of carcinoma ex pleomorphic adenoma compared to de novo adenocarcinoma of major salivary glands

BACKGROUND AND OBJECTIVES

Carcinoma ex pleomorphic adenoma (CXPA) is a rare disease of the major salivary glands that remains poorly characterized. Our objective was to compare the clinical outcomes of patients with CXPA of the major salivary glands to those with de novo adenocarcinomas.

METHODS

Review of the NCDB between 2004 and 2016 to compare cases of CXPA and adenocarcinoma of major salivary glands. Demographics, clinical characteristics, and survival were analyzed.

RESULTS

We identified 1181 patients with CXPA and 3326 patients with adenocarcinoma of major salivary glands. Adenocarcinomas presented with higher rates of nodal metastasis (54.7% vs. 30.4%, p < .001). Five-year survival of adenocarcinoma (55.8%) was worse than that of CXPA (68.5%, p < .001). When stratified by nodal status, there was no significant difference in 5-year survival between CXPA and adenocarcinoma node-negative (75.3% vs. 71.6%, respectively) and node-positive (40.4% vs. 36.1%, respectively) patients.

CONCLUSIONS

CXPAs of the major salivary glands present at an earlier stage with lower rates of regional metastasis compared to adenocarcinomas. After controlling for lymph node metastases, the outcomes are quite similar.

Histopathological Findings of Intraoral Pleomorphic Adenomas: A Retrospective Study of a Case Series

The aim of this study was to describe the clinicopathological features of 21 cases of intraoral pleomorphic adenoma (PA), with emphasis on histopathological findings. Between 2000 and 2016, all patients diagnosed as intraoral PA were retrieved and histopathological slides stained with hematoxylin and eosin reviewed to confirm the diagnosis. All tumors were classified histologically according to Seifert et al (1980). The clinical and histopathological variables were analyzed using the Fisher's exact test, considering a significance level of 5% (P < .05). Plasmacytoid (85.7%), spindle (38.1%), and epithelioid (9.5%) myoepithelial cells were observed. Oncocytic (47.6%) and mucous (19%) cells were also found. The stroma was predominantly fibrous (95.2%), followed by myxoid (66.7%), hyaline (61.9%), and chondromyxoid (33.3%). Squamous (57.1%), adipose (47.6%), sebaceous (14.3%), and bone (14.3%) differentiations were found. Additionally, a group of tumors presented pleomorphism (23.8%), mitoses (14.3%), capsule infiltration (9.5%), and necrosis. The presence of cystic structures occurred significantly in patients older than 30 years (P = .04) and mitoses were more observed in PA from buccal mucosa (P = .026). All cases that presented plasmacytoid cells were smaller than 1.5 cm (P = .015). All tumors with up to 50% stroma area presented with size smaller than 2.0 cm (P = .013). Intraoral PA presents a large morphological spectrum and several microscopic features are associated with clinical findings.