Histopathological insights of adenoid cystic carcinoma in the parotid gland: a case report

¹Department of Pathology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Sawangi (Meghe), Wardha, Maharashtra, India, ²Indira Gandhi Government Medical College and Hospital, Nagpur, Maharashtra, India

^&Corresponding author
Shivali Kalode, Department of Pathology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Sawangi (Meghe), Wardha, Maharashtra, India

Introduction    

Salivary gland tumors are rare as 2%-7% of all head and neck neoplasms [1]. Minor salivary glands are small glands that mostly secrete mucus; they can develop like major salivary glands, which are parotid, submandibular, and sublingual [1]. Peak incidence has a wide age distribution, but mostly affects women in their fifth and sixth decades of life [2]. They typically grow slowly and aggressively invade nearby structures. Compared with lymphatic spread, hematogenous spread occurs more frequently, and the lung, bone, and viscera are the typical sites of metastasis [3]. Liver metastases frequently occur simultaneously or metachronously with metastases to other organs, such as the lung [4]. Based on the solid components of the tumor, ACC has historically been classified into three histological groups: cribriform, tubular, and solid [5]. Greater over-expression of p53 and Ki-67 was seen in the undifferentiated component's immunohistochemical analysis as compared to the conventional ACC, Her-2/Neu had negative values in both parts [6].

Patient and observation     

Patient information: a 65-year-old male came to the outpatient department of surgery at Sawangi (Meghe) Wardha with the chief complaint of swelling in the right preauricular region for two months. According to the patient, the swelling gradually increased in size. The patient has a personal history of smoking for the past 30 years. Other medical history was non-contributory.

Clinical findings: an extraoral assessment of the patient showed a swelling in the right preauricular region of size 2 x 2 cm with an intact surface. The swelling was not adherent to the underlying bone (Figure 1).

Timeline of the current episode: swelling over the right preauricular region for 2 months, gradually increasing to the present size.

Diagnostic assessment: an MRI neck showed well-defined altered signal intensity lesions in the superficial lobe of the right parotid gland, suggestive of neoplastic etiology (Figure 2). Following the report, the swelling was excised, and the specimen was sent for histopathological diagnosis. Grossly, the excised specimen was received in multiple tissue pieces which were friable altogether measuring 3 x 2 x 1 cm, the cut section was greyish-white (Figure 3). Under a 40X high-power microscope, inner ductal and outside myoepithelial cells were seen. The ductal cells have eosinophilic cytoplasm and are cuboidal in shape with angulated and basaloid myoepithelial cells (Figure 4).

Diagnosis: histopathological findings confirmed the diagnosis of Adenoid cystic carcinoma (ADCC)- tubular variant.

Therapeutic interventions: wide surgical excision with clear margins was done.

Follow-up and outcome of interventions: the patient had no metastases found, and he is receiving routine follow-up care.

Patient perspective: the course of therapy and the patient's level of recovery pleased the patient.

Informed consent: the patient granted their written, informed consent for the case report and any related images to be published.

Discussion     

Adenoid cystic carcinoma (ADCC) is primarily found in secretory glands, particularly the salivary glands, and makes up 1% of all head and neck cancers [1]. Even though ADCCs typically grow slowly, there is a lower long-term prognosis due to frequent distant metastases and local recurrences [1]. Histology indicates that ADCC is composed of a combination of epithelial and ductal cells arranged in three different patterns: cribriform, tubular, and solid. These cells are combined to form the majority of malignancies [2]. These metastases grow more slowly than those from other cancers, and as this example shows, long-term survival is still possible even with several metastases [3]. Chemotherapy may be a viable treatment choice for metastatic illness in certain patients [3].

Conclusion     

Adenoid cystic carcinoma (ADCC) should always be considered as a differential diagnosis of Salivary gland neoplasms. For patients with ADCC, maintaining normal functionality, preventing distant metastases, and achieving local control are the main goals of treatment. Early identification and continued patient monitoring are crucial since ADCC of the head and neck is a common malignant tumor of small salivary glands that has the potential to invade surrounding tissues and migrate to other sites. Additionally, this case report advances accurate diagnosis and treatment by referencing previous research and articles.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Shivali Kalode: concept and design, analysis or interpretation of data, manuscript drafting, and is responsible for every part of the work. Sarang Banait: conceptualization and design, data collection, analysis, and interpretation, critical evaluation, and task monitoring. All the authors have read and agreed to the final manuscript.

Figures     

Figure 1: swelling in the right preauricular region

Figure 2: well-defined altered signal intensity lesions in the superficial lobe of the right parotid gland

Figure 3: cut-section of an excised specimen of swelling

Figure 4: under a 40X high-power microscope, inner ductal and outside myoepithelial cells were seen; the ductal cells have eosinophilic cytoplasm and are cuboidal in shape with angulated and basaloid myoepithelial cells

References