Invasive myoepithelial carcinoma ex pleomorphic adenoma of the major salivary gland: two case reports

18F-FDG and 68Ga-FAPI-04 PET/CT Findings of a Rare Epithelial-myoepithelial Carcinoma Arising From Ex Pleomorphic Adenoma of Parotid

Epithelial-myoepithelial carcinoma (EMC) is a rare low-grade salivary gland neoplasm. Distant metastasis is rare, and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has been used to determine the metastatic disease in EMC. 68Ga-fibroblast activation protein inhibitors (FAPI) PET/CT is a promising imaging modality for diagnostic and theognostic purposes in various malignancies. Comparison studies with 18F-FDG have investigated the role of 68Ga-FAPI PET/CT. Herein, we present 18F-FDG and 68Ga-FAPI-04 PET/CT findings of a 51-year-old woman with metastatic EMC arising from ex-pleomorphic adenoma of the parotid.

Metastatic Myoepithelial Carcinoma Ex Pleomorphic Adenoma of the Sublingual Salivary Gland

Myoepithelial carcinoma ex pleomorphic adenoma is a very rare malignant neoplasm of the salivary gland. Owing to its rarity, its clinical features and treatment are not well characterized. We describe a case of a patient who was referred to our department with a six-month history of a bulge on the right side of the floor of the mouth and a submandibular mass with progressive enlargement. The mass was resected, and an elective level I neck dissection was performed. Histological examination revealed myoepithelial carcinoma ex pleomorphic adenoma of the sublingual salivary gland. Thoracic computed tomography and biopsy revealed lung metastases. The patient died two years after the diagnosis.

Epithelial-myoepithelial carcinoma of the nasopharynx: A case report and review of the literature

Background

Epithelial-myoepithelial carcinoma (EMCa) is a rare low-grade malignant tumor that most commonly occurs in the salivary glands, with approximately 320 cases having been reported worldwide. Here, we report the third case of EMCa occurring in the nasopharynx. Rare cases in the breast, pituitary gland, lacrimal gland, nose, paranasal sinus, nasal cavity, trachea and bronchus, lung, and even the pleura mediastinalis have also been reported. Histopathology and immunohistochemistry are useful for confirming the diagnosis of EMCa, which is characterized by biphasic tubular structures composed of inner ductal and outer clear myoepithelial cells and stains for different markers in each layer. However, because of the rarity of EMCa, the clinicopathological characteristics and treatment of these patients remain unclear.

Case presentation

We report a rare case of EMCa of the nasopharynx. A 51-year-old man presented with a 5-month history of pain while swallowing and aggravation accompanied by right ear tinnitus lasting for 1 month. Nasopharyngoscopy and magnetic resonance imaging (MRI) of the nasopharynx and neck revealed a 5.6 cm × 3.4 cm × 3.1 cm mass in the nasopharyngeal space, invasion of the right cavernous sinus, and lymph node enlargement in the right retropharyngeal space. On 17 April 2019, based on the histopathological and immunohistochemical features, a final diagnosis of EMCa of the right nasopharynx was made. The patient underwent concurrent chemoradiotherapy (CCRT), and his symptoms were relieved after treatment. On 10 January 2022, nasopharynx MRI and biopsy revealed local recurrence, but chest and abdominal computed tomography (CT) showed no obvious signs of metastasis. The local recurrence-free survival (LRFS) period was 33 months.

Conclusion

To the best of our knowledge, this is the third reported case of EMCa in the nasopharynx and the only case of EMCa in the nasopharynx treated with CCRT, and a partial response was achieved. Therefore, to improve the quality of life and prognosis of patients with unresectable tumors, we believe that CCRT is a suitable option. Further clinical observations are required to elucidate the pathophysiology and prognosis of EMCa.

Comparative Longitudinal Analysis of Malignant Transformation in Pleomorphic Adenoma and Recurrent Pleomorphic Adenoma

Background: Recurrence in pleomorphic adenoma (PA) has been debated as a risk factor for malignant transformation (MT). In this study, we investigated whether recurrence is a risk factor for MT, by longitudinally analyzing cases with recurrent PA (RPA), and carcinomas from PA (CXPA) or RPA (CXRPA). Methods: The study population included 24 CXPA, 24 RPA, 6 CXRPA, and 386 PA cases (study period 2010−2018). Time and event data were collected from the medical documents to identify the time−event sequences. Results: The time interval to MT in CXRPA was significant longer than that of benign recurrence (median 342.0 vs. 109.5 months). In CXRPA, the recurrence intervals were not shorter than those in RPA according to recurrence frequency. Crudely, the MT rate was 5.9% among primary cases and 20.0% among recurrent cases. However, the time-adjusted MT rates increased up to 11.4% (incubation time > 60 months) and 20.0% (>120 months) in primary cases, which were not different from recurrent cases. Conclusion: In these longitudinal analyses, we did not find any clinical evidence that recurrence facilitates MT in the background of PA. Instead, a long incubation time seems to be a key factor for MT of underlying RPA.

[Myoepithelial carcinoma of the parotid gland: a rare tumor with diagnostic challenges]

We report on the occurrence of a myoepithelial carcinoma (MC) of the parotid gland in a 58-year-old female patient, 6 years after total parotidectomy of a locoregional myoepithelioma. Due to the rapid growth in the former resection area, panendoscopy and tumor extirpation of the right parotid region were performed. From a histomorphological and cytomorphological point of view, a hyalinized clear cell carcinoma of the salivary gland was originally diagnosed. After further immunohistochemical investigations and preparation of deeper section levels the morphological picture and immunohistochemical expression pattern corresponded to a myoepithelial carcinoma of the salivary gland, with focal lateral excision margins. Based on the radiological impression of suspicious lymph nodes during the staging examinations and the perineural invasion in the histological findings, modified radical neck dissection of the ipsilateral levels I-V was performed. All lymph nodes were histologically negative. An adjuvant radiotherapy was then initiated. The patient is tumor-free 7 months after surgery and after completing the adjuvant radiation treatment. Clinical assessment of the facial nerve showed House-Brackmann grade 5 facial palsy. The aim of this case report is to describe the difficulties in the diagnostics and treatment of this rare entity.

A case of giant sarcomatoid carcinoma ex-pleomorphic adenoma of the parotid gland

Carcinoma ex pleomorphic adenoma is a rare malignant parotid neoplasm arising from primary or recurrent benign pleomorphic adenoma. Histologically, it can be sub-classified by upwards of eight different variations (e.g., myoepithelial carcinoma, salivary duct carcinoma, adenoid cystic carcinoma sarcomatoid carcinoma). We present the fourth case in the literature of sarcomatoid carcinoma arising from an underlying pleomorphic adenoma of the parotid gland. We present a case of a 47-year-old female who consulted for a left parotid mass of 15cm long axis. There was no facial paralysis. Fine needle aspiration cytology smears showed a pleomorphic adenoma. The parotid MRI showed a left parotid mass, with heterogeneous signal (hyposignal T1 and hypersignal T2 and in diffusion sequences). The patient underwent a total parotidectomy with a pleomorphic adenoma on extemporaneous examination. Histological examination of the part revealed a pleomorphic adenoma on which a sarcomatoid carcinoma developed. Therefore, a second operation occurred. We performed selective lymph node dissection carrying out the sectors I, II and III followed by radiotherapy. The evolution was favorable. In addition to its rarity, our case joins historical cases by its huge size.

Epithelial-myoepithelial carcinoma originating from a minor salivary gland in the nasal septum: A case report and literature review

RATIONALE

Epithelial-myoepithelial carcinoma is an extremely rare, malignant neoplasm that occurs most frequently in the major salivary glands and accounts for approximately 1% of all salivary gland neoplasms. Few reports have described the presence of epithelial-myoepithelial carcinoma in the sinonasal region; hence, the treatment guideline and prognosis remain unclear.

PATIENT CONCERNS

We reported a case of a 75-year-old woman with complaint of nasal obstruction and frequent epistaxis for 3 years. During the nasal endoscopic examination, a mass in the left nasal cavity originating from the left nasal septum that caused bleeding on touch was observed.

DIAGNOSES

A diagnosis of epithelial-myoepithelial carcinoma was made based on the features of histopathology and immunohistochemistry of the surgical specimens. The patient was treated by surgical removal of the septal mass using the endonasal endoscopic approach.

OUTCOMES

In the serial follow-up paranasal sinus imaging and endoscopic inspection, evidence of recurrence was absent for 18 months after surgery.

LESSONS

This report highlights a case of epithelial-myoepithelial carcinoma originating from a minor salivary gland in the nasal septum, one of the most unusual locations. Diagnosis of epithelial-myoepithelial carcinoma should be made based on the findings of immunohistochemistry of the operative specimen. Clinicians should consider complete surgical resection as the effective treatment of choice.

Carcinoma ex pleomorphic adenoma: a case report and review of literature

Background

Carcinoma ex pleomorphic adenoma (CA-ex-PA) is extremely unusual in minor salivary glands of oral cavity. CAex-PA is a carcinomatous change as a primary or as a recurrence of pleomorphic adenoma.

Objective

Due to resemblance of clinical symptoms of Ca ex PA and benign pleomorphic adenoma, it is mandatory for surgeons to keep high degree of clinical alertness, considering the peculiarity of this tumor.

Case Report

54-year-old male presented with swelling on left side in the pre-auricular region from the middle of zygomatic arch to mastoid process and from tragus of the ear up to angle of mandible. Fine needle aspiration cytology revealed a mixture of benign and malignant components. Total left parotidectomy with left radical neck dissection followed by reconstruction with cervicodeltopectoral flap was performed. Combination of chemotherapy and radiotherapy were given to patient. Histologic examination and pre-operative fine needle aspiration cytology confirmed the diagnosis of Carcinoma ex pleomorphic adenoma (CA-ex-PA). Two-year follow-up of patient showed no recurrence of the lesion.

Conclusion

Due to the similarity in the clinical symptoms of CA-ex-PA and benign pleomorphic adenoma, it is vital that clinicians maintain a high degree of clinical vigilance, considering the oddity of this malignancy.

Effective chemotherapy for submandibular gland carcinoma ex pleomorphic adenoma with lung metastasis after radiotherapy: A case report

BACKGROUND

Only a few cases of carcinoma ex pleomorphic adenoma arising in the submandibular gland have ever been reported, all with a poor prognosis. The standard treatment for salivary gland carcinoma ex pleomorphic adenoma is surgical resection combined with postoperative radiotherapy, but the necessity of chemotherapy as well as the most appropriate treatment regimen for patients with distant metastasis after radiotherapy remains controversial.

CASE SUMMARY

This report presents the case of a 73-year-old woman who suffered submandibular gland carcinoma ex pleomorphic adenoma. She accepted surgery to remove the mass; she was found to have lung metastasis after radiotherapy. Her condition was controlled by chemotherapy with liposomal doxorubicin plus cisplatin.

CONCLUSION

The positive clinical outcome in the patient reveals that this chemotherapy regimen may be an alternative treatment for such a condition.