Clinicopathological observation of primary lung enteric adenocarcinoma and its response to chemotherapy: A case report and review of the literature

Abstract

Primary lung enteric adenocarcinoma is a rare type of invasive lung carcinoma. Its morphology and immunohistochemistry are those of colorectal carcinoma, but there is no associated primary colorectal carcinoma. The present study describes the case of a 53-year-old female who presented with an irritating cough and a mass around the right sternoclavicular joint. Comprehensive evaluation revealed involvement of the mediastinum, lungs, right sternoclavicular joint and right kidney. Biopsies from the mediastinal and right sternoclavicular joint tumors showed features of adenocarcinoma. Immunohistochemistry was positive for cytokeratin (CK)20 and caudal type homeobox transcription factor 2, and negative for CK7, thyroid transcription factor-1 and napsin A. Genotypic analysis identified the expression of wild-type epidermal growth factor receptor, Kirsten rat sarcoma viral oncogene homolog, serine/threonine-protein kinase B-Raf and UDP-glucuronosyltransferase 1-1. There was no expression of echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase and a moderate expression of excision repair cross-complementation group 1, ribonucleoside-diphosphate reductase large subunit and tubulin β-3 chain. A strong expression of thymidylate synthase and 677TC genotype expression of methylenetetrahydrofolate reductase was observed. Gastroscopy, enteroscopy, colorectal colonoscopy and positron emission tomography-computed tomography failed to find evidence of a gastrointestinal malignancy and primary lung enteric adenocarcinoma was diagnosed. The presence of multiple metastases did not permit curative surgery. The patient was treated with 3 monthly cycles of the XELOX chemotherapy regimen; the response was poor with progression of supraclavicular lesions. Treatment was switched to the TP regimen for 4 monthly cycles, which resulted in a significant reduction in the size of the lung lesions; however, the supraclavicular lesion responded poorly to the treatment. The patient then received 2 cycles of the FOLFIRI regimen; however, the lung and right supraclavicular lesions progressed, causing increased right upper limb pain. The pain was alleviated by palliative surgery. Following surgery, the DP regimen was employed. Follow-up of the patient remains ongoing. The present findings suggest that the early diagnosis and treatment of primary lung enteric adenocarcinoma is likely to improve patient outcome.

Clinicopathological, radiographic, and oncogenic features of primary pulmonary enteric adenocarcinoma in comparison with invasive adenocarcinoma in resection specimens

“…The cytomorphological and immunohistochemical characteristics of PEAC have been described many times from gross morphology to microstructure in the literature, [ 6 , 9 , 10 , 12 , 24 ] and PEACs are morphologically very heterogeneous. [ 10 , 26 ] The results of immunohistochemistry analyses in our series are similar to those of previous studies in PEAC patients.…”

“…[ 6 , 9 – 26 ] Oncogenic driver mutations in PEAC have been reported in case reports, small case series. [ 17 – 24 ] However, it is not known whether there are any distinctive clinical or detailed molecular features.…”

“…However, the expression levels of these immunohistological markers were not consistent in published English literature. [ 10 , 11 , 18 , 24 , 26 ]…”

Diagnostic Pathology of Lung Cancer

“…23 Similarly, enteric adenocarcinoma has the histologic appearance of colorectal adenocarcinoma, and may express CDX2 and/or cytokeratin 20, both of which are typically negative in convention pulmonary adenocarcinomas. 24 Importantly, both variants usually lack nuclear staining for TTF-1 and cytoplasmic expression of napsin A. 23,24 In both settings, the diagnosis of lung primary should only be made after clinical exclusion of underlying hepatocellular carcinoma or adenocarcinoma of the gastrointestinal tract, respectively.…”

“…24 Importantly, both variants usually lack nuclear staining for TTF-1 and cytoplasmic expression of napsin A. 23,24 In both settings, the diagnosis of lung primary should only be made after clinical exclusion of underlying hepatocellular carcinoma or adenocarcinoma of the gastrointestinal tract, respectively.…”