Two cases report of secretory carcinoma of the salivary gland in the lung: one primary and one metastatic after many years

Abstract

Background: Secretory carcinoma of the salivary gland (SCSG) is a recently discovered salivary gland tumor that occurs mostly in the major salivary glands and occasionally in the skin, cervix, trachea, etc.Secretory carcinoma of the lung is extremely rare. To our knowledge, this is the third report of SCSG arising as a primary pulmonary tumor. The two SCSG cases reported in this paper are unique in that one was primary and the other was metastasized to the lung.Case Description: Case 1 is a primary endobronchial tumor in a 66-year-old man. He went to the doctor complaining of fever, cough and yellow phlegm, and his body weight was significantly reduced by 3 kg. The bronchoscope showed the growth of new organisms in the right upper lobe of the lung.Immunohistochemistry of his biopsy specimen was positive for AE1/AE3, Keratin7 (CK7), S-100, mammaglobin, and pan-TRK, but negative for thyroid transcription factor-1 (TTF-1), napsin-A, synaptophysin (SYN), chromogranin A (CGA), and discovered on GIST-1 (Dog-1), and the MKI-67 (Ki-67) proliferation index was 2%. This case lacked the typical ETV-6 gene rearrangement. After one cycle of chemotherapy, the tumor was significantly reduced, and surgical excision was planned. Case 2 was a metastatic secretory carcinoma with a history of parotid pleomorphic adenoma resection 30 years ago and malignant pleomorphic adenoma resection 16 years ago before the study, respectively. He presented with a complaint of a parotid gland mass. Chest CT examination revealed a mass in the upper lobe of the left lung. The biopsy tissue of him exhibited a typical histological appearance under the microscope.Immunohistochemistry was positive for AE1/AE3, CK7, S-100, and mammaglobin; partially positive for estrogen receptor (ER) and pan-TRK; and negative for TTF-1, Napsin-A, SYN, CGA, P63, P40, and Dog-1. The Ki-67 proliferation index was approximately 3%. Fluorescence in situ hybridization (FISH) revealed ETV-6 gene rearrangement. After the diagnosis of SCSG, the patient underwent resection of the lung mass, and there was no recurrence of the lung after 1 month's follow-up. Conclusions: By examining these two cases, we have a better understanding of the clinicopathological features of secretory carcinoma, which will help to improve the accuracy of pathological diagnosis.

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

“…The pulmonary secretory carcinomas were positive for CK7, S100 protein, and mammaglobin, and negative for TTF‐1, p40, and p63, consistent with the pattern of immunoreactivity reported for head and neck secretory carcinoma 183 . Two pulmonary secretory carcinomas harboured ETV6 rearrangement by FISH (Figure 8F), 21,22 one case was positive for ETV6::NTRK3 fusion in a gene fusion panel assay, 23 and one case was positive for pan‐TRK immunohistochemistry but negative for ETV6 rearrangement by FISH 20 . Similarly, approximately 90% of head and neck secretory carcinomas harbour ETV6::NTRK fusions, 184 with a minority showing other fusions that often, but not always, involve ETV6 185 .…”

“…To our knowledge, only four primary pulmonary secretory carcinomas have been reported, all occurring in 51-66-year-old adults, and all but one occurring in an endobronchial location. [20][21][22][23] These tumours show combinations of solid, tubular, microcystic, and papillary growth of low-grade epithelial cells with abundant eosinophilic cytoplasm and associated eosinophilic secretions (Figure 8A-E). The pulmonary secretory carcinomas were positive for CK7, S100 protein, and mammaglobin, and negative for TTF-1, p40, and p63, consistent with the pattern of immunoreactivity reported for head and neck secretory carcinoma.…”

“…183 Two pulmonary secretory carcinomas harboured ETV6 rearrangement by FISH (Figure 8F), 21,22 one case was positive for ETV6::NTRK3 fusion in a gene fusion panel assay, 23 and one case was positive for pan-TRK immunohistochemistry but negative for ETV6 rearrangement by FISH. 20 Similarly, approximately 90% of head and neck secretory carcinomas harbour ETV6::NTRK fusions, 184 with a minority showing other fusions that often, but not always, involve ETV6. 185 Head and neck secretory carcinomas have shown response to TRK targeted therapies, [186][187][188] such that the diagnosis of secretory carcinoma in the lung may have implications for predictive biomarker testing and treatment.…”

“…To our knowledge, only four primary pulmonary secretory carcinomas have been reported, all occurring in 51–66‐year‐old adults, and all but one occurring in an endobronchial location 20–23 …”

“…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.…”