Primary acinic cell carcinoma of the trachea: A case report and literature review

Abstract

Rationale: Salivary gland-type acinic cell carcinoma (ACC) is a low-grade malignancy. Primary ACC of the trachea and lungs is rare; here, we describe 1 such case. The histological morphology of tracheal ACC was similar to that of its salivary gland-associated equivalent. Because of its rarity, it is easily misdiagnosed as another type of tracheal or lung tumor. Microscopic analysis of pathological features and immunohistochemistry help diagnose primary ACC of the trachea and lungs. Patient concerns: A 33-year-old female complained of shortness of breath and hemoptysis for 2 years, and reported the symptoms to have aggravated over the last 4 months. The patient was admitted to our hospital for further treatment. Enhanced computed tomography revealed a soft tissue density nodule shadow in the trachea, which was approximately 1.3 × 1.2 cm in size. Diagnoses: Based on the clinical information, morphological features, and immunohistochemistry, the pathological diagnosis was primary ACC of the trachea. Intervention: The tracheal lesion was resected with an electric snare, electrotomy, freezing, and an argon knife using a rigid bronchoscope. Outcomes: The patient’s postoperative course was uneventful. Lessons: It is important to prevent misdiagnosis of this type of tumor as another type of lung tumor. Morphological and immunohistochemical features can be useful in diagnosing primary ACC of the trachea and lungs.

Recent developments in the pathology of primary pulmonary salivary gland‐type tumours

“…18 Four cases of AciCC were reported to be combined with carcinoid tumour 178,[180][181][182] ; all showed neuroendocrine marker staining including in the AciCC component, 178,[180][181][182] in contrast to lack of expression of neuroendocrine markers in pure AciCCs of the lung. [16][17][18][19]47,[159][160][161]165,166,179 Pulmonary AciCC tends to behave less aggressively than other pulmonary carcinomas. A review of 25 pulmonary AciCC with up to 8 years of follow-up found no deaths, one recurrence, and two cases of lymph node metastasis.…”

“…At least 32 cases of AciCC primary to the lung have been reported. [16][17][18][19] These tumours are usually associated with a bronchus or the trachea, although two cases were found deep in the pulmonary parenchyma. 159,160 Four cases were reported in paediatric patients, aged 4-12 years, 18,46,47 three of which were associated with a foreign body.…”

“…18 AciCC typically show solid or microcystic growth of polygonal serous acinar-type cells containing abundant granular cytoplasm and round, low-grade nuclei. [16][17][18][19] Most cases exhibit a clear-cell component, and some cases show rare mucous cells. 18,161 Certain features of pulmonary AciCC differ from those of head and neck and breast AciCC (Table 4).…”

“…TTF-1, p40, and p63 are negative in pulmonary AciCC. [16][17][18][19]179 A panel of immunostains for distinguishing AciCC from histologically similar entities in the lung may therefore include TTF-1 (to exclude lung adenocarcinoma), p63 (to exclude HCCC and MEC), and mammaglobin and S100 protein (to exclude secretory carcinoma). 18 Four cases of AciCC were reported to be combined with carcinoid tumour 178,[180][181][182] ; all showed neuroendocrine marker staining including in the AciCC component, 178,[180][181][182] in contrast to lack of expression of neuroendocrine markers in pure AciCCs of the lung.…”

“…The most common types of pulmonary salivary gland-type carcinoma include mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), and epithelial-myoepithelial carcinoma (EMC). 6,8,[10][11][12][13] Case reports and series have also described hyalinizing clear cell carcinoma (HCCC), 4,14,15 acinic cell carcinoma (AciCC), [16][17][18][19] secretory carcinoma, [20][21][22][23] salivary duct carcinoma, [24][25][26] intraductal carcinoma, 27,28 and polymorphous adenocarcinoma [29][30][31][32][33] occurring as primary lung tumours. Benign salivary gland-type tumours reported in the lung include myoepithelial tumours and pleomorphic adenomas.…”