Identification of a metastatic lung adenocarcinoma of the palate mucosa through genetic and histopathological analysis: A rare case report and literature review
Journal
BMC Cancer
Journal Volume
19
Journal Issue
1
Date Issued
2019
Author(s)
Abe M
Watanabe K
Shinozaki-Ushiku A
Ushiku T
Abe T
Fujihara Y
Amano Y
Zong L
Kubo E
Inaki R
Kinoshita N
Yamashita S
Takai D
Ushijima T
Nagase T
Hoshi K.
Abstract
Background: Cancers of unknown primary origin (CUPs) are reported to be the 3-4th most common causes of cancer death. Recent years have seen advances in mutational analysis and genomics profiling. These advances could improve accuracy of diagnosis of CUPs and might improve the prognosis of patients with CUPs. Case presentation: A 76-year old male with an adenocarcinoma of unknown primary origin in the lung presented with another tumor of the palate mucosa. The tumor cells in the pleural effusion were all negative for immunohistochemical markers (TTF-1 and Napsin A) and lung-specific oncogenic driver alterations (EGFR mutation and ALK translocation). The tumor of the palate mucosa was likewise identified as an adenocarcinoma, and the cells showed cytological similarities with the tumor cells in the pleural effusion; TTF-1, Napsin A, EGFR mutation and ALK translocation were all negative. This result suggested that origins of the tumors of the palate mucosa and in the lung were the same, even though the origin had not yet been determined. Next, we addressed whether the tumor of the palate mucosa was a primary tumor or not. Secretory carcinoma (SC), which is a common type of minor salivary gland tumor (MSGT), was suspected; however, mammaglobin was negative and ETV6-NTRK3 (EN) fusion was not observed. Other MSGTs were excluded based on histological and immunohistochemical findings. Furthermore, an additional examination demonstrated an oncogenic KRAS mutation at codon 12 (p.G12D) in both palate tumor and in pleural effusion. KRAS mutation is known to exist in one-third of lung adenocarcinomas (LUADs), but quite rare in MSGTs. The possibility of metastasis from other organs was considered unlikely from the results of endoscopic and imaging studies. This result indicated that the primary site of the CUP was indeed the lung, and that the tumor of the palate mucosa was a metastasis of the LUAD. Conclusions: A tumor of the palate mucosa that showed diagnostic difficulties was determined to be a metastatic LUAD by genomic alterations and histopathological findings. ? 2019 The Author(s).
Subjects
Cancer of unknown primary origin (CUP); Lung adenocarcinoma; Metastatic cancer; Minor salivary gland tumor (MSGT); Occult primary tumor
SDGs
Other Subjects
anaplastic lymphoma kinase; biological marker; carboplatin; carcinoembryonic antigen; epidermal growth factor receptor; fluorodeoxyglucose f 18; homeobox protein Nkx 2.1; mammaglobin; napsin A; paclitaxel; unclassified drug; ALK protein, human; anaplastic lymphoma kinase; cytokeratin 7; epidermal growth factor receptor; KRAS protein, human; protein p21; tumor marker; aged; ALK gene; bone metastasis; cancer combination chemotherapy; cancer of unknown primary site; carcinogenesis; case report; clinical article; codon; cytology; EGFR gene; endoscopy; ETV6 NTRK3 gene; gene fusion; gene mutation; gene translocation; genetic analysis; histopathology; human; human cell; human tissue; immunohistochemistry; lung adenocarcinoma; lung nodule; lymph node metastasis; male; medical history; metastatic lung adenocarcinoma; minor salivary gland tumor; nuclear magnetic resonance imaging; oncogene K ras; palate; palate mucosa; palate mucosa tumor; physical examination; pleura effusion; pleural dissemination; positron emission tomography-computed tomography; Review; salivary gland tumor; secretory carcinoma; thorax pain; tumor cell; tumor classification; diagnostic imaging; dna mutational analysis; genetic screening; genetics; lung adenocarcinoma; metabolism; mouth mucosa; mutation; palate; pathology; x-ray computed tomography; Adenocarcinoma of Lung; Aged; Anaplastic Lymphoma Kinase; Biomarkers, Tumor; DNA Mutational Analysis; ErbB Receptors; Genetic Testing; Humans; Immunohistochemistry; Keratin-7; Male; Mouth Mucosa; Mutation; Palate; Proto-Oncogene Proteins p21(ras); Tomography, X-Ray Computed
Publisher
BioMed Central Ltd.
Type
review