Myoepithelial carcinoma of the parotid: a rare tumour that may provide diagnostic difficulty

Pleomorphic adenoma of hard palate: Review of updated literature and "case report"

RATIONAL

Pleomorphic adenoma (PA) is a rare benign tumor mainly affecting the major salivary glands, known for its diverse histological appearances that can mimic malignancies. When it occurs in the hard palate it present diagnostic and management challenges compared to other sites due to the anatomical location and potential proximity to critical structures. This case reports a rare presentation PA starting as an ulcer, alongside a review of rare cases of PA reported in last 5 years. We aim to highlight clinical challenges and emphasize the need for awareness in diagnosis of this diverse entity amongst the clinicians before reaching a definitive conclusion.

PATIENT CONCERNS

A 41-year-old female reported an asymptomatic large swelling on the right side of the posterior palatal region. Clinical diagnosis revealed a firm, rubbery, and non-tender swelling of approximately 4 cm × 4 cm diameter. A triangular incisional biopsy was performed to confirm the diagnosis.

DIAGNOSIS

The histopathological evaluation confirmed the presence of a PA with a well-encapsulated and compressed salivary gland. A wide surgical dissection was made to remove the entire encapsulated tumor mass, including the mucoperiosteum and eroded bone of the palate. The borderline of the tumor was carefully identified in the surrounding healthy tissue. The hemostasis was obtained using a simple interrupted suture.

LESSON

The diagnosis of PA is difficult as it usually involves extensive squamous and mucous metaplasia, confusing it with malignant disorders. Histopathological and clinical examinations are important for differentiating this lesion from other tumors. Complete surgical excision is reported as the first line of treatment.

[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.

18F-FDG PET/CT Findings in a Rare Myoepithelial Carcinoma Arising in the Parapharyngeal Space

Myoepithelial carcinoma is an exceedingly rare malignant neoplasm that most frequently occurs in the salivary gland. We here report a case of myoepithelial carcinoma in a 57-year-old man. Unenhanced and contrast-enhanced CT scans showed an ill-defined, heterogeneous, contrast-enhancing mass in the left parapharyngeal space, which suggested malignancy. F-FDG PET/CT showed a hypermetabolic mass and multiple FDG-avid lymph nodes in the bilateral cervical regions. An incision biopsy was performed, and the pathological examination confirmed the mass to be a myoepithelial carcinoma.