SALIVARY ADENOID CYSTIC CARCINOMA: AN UNCOMMON SALIVARY-TYPE OF LUNG CANCER

Abstract

SESSION TITLE: Medical Student/Resident Lung Cancer Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Adenoid cystic carcinoma (ACC) is a rare salivary gland-type lung malignancy with an estimated incidence of 0.04-0.2% [1]. Tumors typically occur in the major airways and may have submucosal invasion [2]. Common presenting symptoms include chest pain, hemoptysis, and dyspnea. We report a patient with non-specific chest pain found to have primary ACC of the lung. CASE PRESENTATION: A 55-year-old female non-smoker with history of hypertension and diabetes presented with worsening headache, neck, chest, and back pain following a motor vehicle accident four days prior. She further clarified that she had been experiencing left-sided chest pain radiating to her left shoulder for one year. Physical examination was remarkable only for midline neck and back tenderness. Initial labs were unremarkable. Chest radiography identified a left sided suprahilar opacity. This prompted a computed tomography (CT) scan of her chest which demonstrated a 2.9 x 2.3cm left sided suprahilar mass with splaying of the underlying vascular structures [Figure 1A]. Positron emission tomography CT scan showed avid fluorodeoxyglucose uptake in the left upper lobe [Figure 1B]. Bronchoscopy was performed which revealed a smooth mass within the left main bronchus that had increased vascularity with narrow band imaging [Figure 2]. Endobronchial biopsies confirmed ACC and prompted referral for a left upper lobe lobectomy. Pathological analysis was consistent with a Grade II, moderately differentiated adenoid cystic carcinoma. Surgical margins and 0/23 lymph nodes were negative for malignancy. She was ultimately staged pT2N0M0 with an R0 resection. On follow-up with hematology-oncology, it was determined that the patient would not require adjuvant chemoradiation. She remains on active surveillance without any evidence of tumor recurrence at 12-month follow-up. DISCUSSION: Diagnosis and staging for ACC requires a combination of radiographic imaging and bronchoscopy with biopsy. Histological sub-types include cribriform, tubular, and solid, the latter being more aggressive [2]. Surgical resection is the cornerstone of management providing the best prognosis. A case series of 26 patients who underwent R0 surgical resection of primary ACC observed an overall survival rate of 91.7% at 5-years [3]. A similar benefit was also seen with adjuvant radiotherapy in R1 resections. In those who are not surgical candidates, survival is 0% at 5-years. In non-surgical patients, chemoradiation is often ineffective as ACC responds poorly to currently available chemotherapeutics. CONCLUSIONS: ACC is an uncommon type of lung cancer. Tumors have a high likelihood of submucosal extension and local recurrence. Complete surgical resection offers the best prognosis. In contrast, chemoradiation has a limited role in non-surgical candidates. Reference #1: W. D. Travis, L. B. Travis, and S. S. Devesa, “Lung cancer,” Cancer, vol. 75, no. 1 S, pp. 191–202, 1995, doi: 10.1002/1097-0142(19950101)75:1+<191::AID-CNCR2820751307>3.0.CO;2-Y. Reference #2: H. Inoue, A. Iwashita, H. Kanegae, K. Higuchi, Y. Fujinaga, and I. Matsumoto, “Peripheral pulmonary adenoid cystic carcinoma with substantial submucosal extension to the proximal bronchus,” Thorax, vol. 46, no. 2, pp. 147–148, 1991, doi: 10.1136/thx.46.2.147. Reference #3: M. M. Hu, Y. Hu, J. B. He, and B. L. Li, “Primary adenoid cystic carcinoma of the lung: Clinicopathological features, treatment and results,” Oncol. Lett., vol. 9, no. 3, pp. 1475–1481, Mar. 2015, doi: 10.3892/ol.2015.2859. DISCLOSURES: No relevant relationships by Ethan Karle, source=Web Response No relevant relationships by Armin Krvavac, source=Web Response No relevant relationships by Michael Nance, source=Web Response No relevant relationships by Tarang Patel, source=Web Response