Unraveling Adenoid Cystic Carcinoma

Diagnostic and Therapeutic Strategies in Salivary Gland Tumors with Challenging Prognosis

Abstract

Introduction: Case study of woman 55-year-old, single, retired female patient who presented with a painless, slowly growing swelling in the right submandibular region for approximately 8 months, accompanied by mild dysphagia for the last two months. The absence of systemic symptoms, such as pain, fever, or weight loss, initially made the presentation clinically nonspecific. Still, the persistent swelling and its characteristics on physical examination and imaging raised strong suspicion of salivary gland neoplasia.

Methods: The diagnostic process included a detailed clinical evaluation and sequential complementary exams. Initially, basic laboratory tests were performed, showing results within normal limits, except for a mild, nonspecific elevation of C-reactive protein. Imaging investigation began with an ultrasound of the cervical region, which revealed a hypoechoic, solid, and vascularized nodular mass in the right submandibular gland. A contrast-enhanced CT scan of the neck confirmed the mass, with no signs of invasion of adjacent structures or lymph node enlargement. Ultrasound-guided fine-needle aspiration biopsy was suggestive of salivary gland neoplasia, but not definitive.

Results: Histopathological examination of the surgical specimen confirmed the diagnosis of adenoid cystic carcinoma of the submandibular gland, classified as low/intermediate grade. The surgical margins were considered clear, but focal perineural invasion was identified, a crucial finding due to its prognostic impact. Based on the perineural invasion, the patient was referred for adjuvant radiotherapy with the Intensity Modulated Radiation Therapy technique. Acute side effects were observed and managed during radiotherapy.

Conclusion: This case of adenoid cystic carcinoma of the submandibular gland demonstrates the importance of early diagnosis and a multimodal approach in the treatment of salivary gland tumours, especially those with risk factors such as perineural invasion. The patient was successfully treated with surgery and adjuvant radiotherapy. Still, the aggressive nature and propensity of adenoid cystic carcinoma to late recurrence and distant metastases require rigorous and continuous long-term follow-up, with periodic clinical examinations and serial imaging studies (neck and chest CT scans), to monitor disease recurrence and optimise the patient's survival and quality of life.