|Year : 2021 | Volume
| Issue : 4 | Page : 301-303
Primary adenoid cystic carcinoma of the lung
Renuka Masodkar1, Mano Bhadauria1, PK Das2, S Zaidi3
1 Department of Radiation Oncology, Indraprashtha Apollo Hospital, New Delhi, India
2 Department of Medical Oncology, Indraprashtha Apollo Hospital, New Delhi, India
3 Department of Surgical Oncology, Indraprashtha Apollo Hospital, New Delhi, India
|Date of Submission||18-May-2021|
|Date of Decision||13-Jul-2021|
|Date of Acceptance||16-Jul-2021|
|Date of Web Publication||30-Aug-2021|
Department of Radiation Oncology Indraprashtha Apollo Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
Primary adenoid cystic carcinoma (ACC) of the lung is a very uncommon thoracic neoplasm. In view of rarity of this entity, the management guidelines are not well defined. We report a case of primary ACC of the lung managed with surgery and adjuvant chemoradiation.
Keywords: Adenoid cystic carcinoma, lung, radiotherapy
|How to cite this article:|
Masodkar R, Bhadauria M, Das P K, Zaidi S. Primary adenoid cystic carcinoma of the lung. Apollo Med 2021;18:301-3
| Introduction|| |
Adenoid cystic carcinoma (ACC) is a distinctive malignant neoplasm that usually arises in submandibular and palate salivary glands. Primary ACC of the lung is an extremely rare entity accounting for 0.04%–0.2% of all primary lung cancers. We report a case of primary ACC of the lung treated with surgery and adjuvant chemoradiotherapy.
| Case Report|| |
A 40-year-old hypertensive male presented with complaints of progressive nonproductive cough and progressive shortness of breath for 2 months. Computed tomography (CT) scan thorax showed a large (48 mm × 34 mm) irregular heterogeneously enhancing mass in the right tracheobronchial region involving both anterior and posterior segment of upper lobe abutting mediastinal vessel and trachea. Bronchoscopy revealed a soft-white mass arising from trachea causing occlusion of intermediate bronchus on the right side [Figure 1]. Whole-body positron emission tomography (PET)/CT scan showed a fluorodeoxyglucose (FDG) avid heterogeneously enhancing hypodense mass lesion in the right tracheobronchial region measuring 2.7 cm × 2.6 cm × 3.1 cm. The mass was encasing the right upper lobe bronchus with nonFDG-avid near-complete distal collapse-representing primary mitotic lesion [Figure 2]. No FDG-avid visible mitotic disease was seen elsewhere. Endobronchial biopsy showed ACC [Figure 3]. On immunohistochemistry, tumor cells were found to be CD117 (c-kit) positive.
|Figure 1: Bronchoscopy showing soft white mass arising from trachea causing occlusion of intermediate bronchus on the right side|
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|Figure 2: Axial (a),coronal (b) and sagittal(c)computed tomography scan images showing mass in right tracheobronchial region|
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He underwent the right upper lobe sleeve lobectomy + intraoperative frozen section and latissimus dorsi flap reconstruction. Surgical histopathology showed Grade 2 ACC, involving the right upper lobar bronchus, maximum tumor dimension was 2.2 cm, transmural infiltration of wall of the right upper lobar bronchus with extension into adjacent lung parenchyma was noted. There was an intraluminal and submucosal spread of tumor. Lymphovascular tumor emboli were absent; perineural invasion was seen. There was a direct extension of tumor into hilar fat. Two out of eight peribronchial lymph nodes showed tumor micrometastases without perinodal spread. The proximal right bronchial margin showed infiltration of adventitia by tumor. Distal right bronchial margin showed patchy involvement by tumor. Mediastinal nodes were free. The tumor was staged as P T1c N1-Stage IIB.
He was then planned for adjuvant chemoradiotherapy. He received 58 Gy in 29 fractions to tumor bed and regional lymphatics using image-guided radiotherapy. He received six cycles of concurrent weekly paclitaxel chemotherapy along with radiation. After 2 years of follow-up, he is asymptomatic with PET/CT scan showing no disease recurrence.
| Discussion|| |
Primary ACC of the lung is an uncommon salivary gland–type malignant neoplasm that occurs rarely as a primary tumor of the airway. The data on its clinical, pathological features, treatment modalities, and outcomes are sparse owing to its low incidence.
ACC of the lung tends to occur in younger patients, with male/female ratio of 1:1. In most of the studies, smoking is not associated with etiology for ACC of the lung.
The tumor is centrally located in 90% of the cases; hence, the symptoms are due to bronchial obstruction such as dyspnea, cough, and wheezing.
These neoplasms are generally slow growing. They are poorly defined, sessile, nodular growths that may ulcerate centrally but usually infiltrate into the adjacent lung parenchyma and hilar lymph nodes by direct invasion. Apart from direct extension, these tumors also spread by perineural invasion and the hematogenous route.
Microscopically, ACC is composed of uniform population of dark-staining, basaloid tumor cells containing a minimal amount of cytoplasm, and arranged in three growth patterns: cribriform, solid, and tubular.
The primary modality of the treatment for ACC is surgical resection. Sleeve resection, lobectomy, or pneumonectomy is common surgical procedures depending on the size and extent of disease. The resection margins may be positive for tumor cells due to extensive invasion along the airway. The role of adjuvant treatment is not well defined. However, it is a relatively radiosensitive tumor, so adjuvant radiotherapy may be beneficial., Studies by Chopra et al. and Hyoung et al. have shown that adjuvant radiotherapy is effective in eradicating microscopic residual disease. Definitive radiotherapy may help in long-term survival of > 50% of the patients with unresectable disease.
These tumors are generally not sensitive to chemotherapy. C-kit expression on immunohistochemistry is found in ACC of the head and neck. Since these tumors show c-kit overexpression, the role of oral targeted therapies such as tyrosine kinase inhibitors such as imatinib and immunotherapy needs to be explored in this category of lung cancer patients. In a phase II trial, nine out of 15 patients showed stable disease after the use of imatinib mesylate in patients with ACC of the salivary glands.
Long-term survival can be expected, since it is a low-grade malignancy. However, long-term recurrences even after a period of 10 years may be occur, so regular follow-up of the patients is mandatory.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]