Presenting with dysphagia and dyspnea, Rapidly worsening lung adenocarcinoma due to Diffusely spreading Lymphangitic carcinomatosis: A case reportSatoshi Tanaka, Ryo Matsubayashi, Shunichi Tamori,Katsuhiko Saito, Satoshi Nomura・Author affiliationsSatoshi Tanaka;Toyama City Hospital, Respiratory medicine.Kanazawa University Hospital, Respiratory medicine.satoshi34444433@gmail.comConceptualization, Investigation, and Writing – original draft.Ryo Matsubayashi;Toyama City Hospital, Respiratory medicine.Kanazawa University Hospital, Respiratory medicine.matsubayashi1120@gmail.comWriting – review & editing.Shunichi TamoriToyama City Hospital, Respiratory medicine.shun.tamori@gmail.comWriting – review & editing.Katsuhiko SaitoToyama City Hospital, Pathology.katsu-s@tch.toyama.toyama.jpWriting – review & editing.Satoshi NomuraToyama City Hospital, Respiratory medicine.sts_nom_kmh08@yahoo.co.jpWriting – review & editing.・Data availability statement; No datasets were generated or analyzed during this case report.・Funding statement; The authors received no specific funding for this work.・Conflict of interest disclosure; The authors declare no conflicts of interest in association with the present study.・Ethics approval statement; None・Patient consent statement; Written informed consent was obtained from the patient’s family.・Permission to reproduce material from other sources; No material from other sources was used for this work.・Clinical trial registration; NoneKey Clinical MessageLymphangitic carcinomatosis is a metastatic disease with a poor prognosis and poorly understood pathophysiology. We present a case of rapidly worsening lung adenocarcinoma with diffusely spreading cancerous lymphangitis in lung, mediastinum, retroperitoneum, and gastrointestinal tract. Our findings suggest cancer dissemination in this patient was predominantly caused by direct lymphatic invasion.Key words; Non-small-cell lung carcinoma, Lymphangitic carcinomatosisCase PresentationA 60-year-old man presented with progressive dysphagia and dyspnea for four days. He had an 80-pack-year smoking history. Chest radiography revealed a tumor in the right upper lung field and bilateral reticulations (Figure 1A). Computed tomography (CT) revealed a tumor in the right upper lobe with bilateral bronchovascular bundle thickening and esophageal wall thickening (Figure 1B). Magnetic resonance imaging (MRI) showed multiple brain tumors. Fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) demonstrated FDG uptake in these lesions, as well as in the left adrenal gland, and thoracic and abdominal lymph nodes (Figure 1C). Esophagogastroduodenoscopy (EGD) revealed esophageal stenosis with a relatively smooth epithelium (Figure 2A) and a duodenal ulcer (Figure 2B-left). Upon biopsy, only the duodenum yielded thyroid transcription factor-1 (TTF-1) positive adenocarcinoma cells in the lamina propria mucosae (Figure 2B-right). Endobronchial ultrasound-guided transbronchial biopsy with a guide sheath (EBUS-GS-TBB) of the right upper lobe tumor revealed TTF-1 positive poorly differentiated adenocarcinoma (Figure 2C), which was strongly positive for programmed death-ligand 1 (PD-L1). However, no driver gene abnormality was detected on the OncomineTM Dx Target Test (Thermo Fisher Scientific, Waltham, MA, USA). Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of the esophagus revealed adenocarcinoma cells (Figure 2D). Based on these findings, the patient was diagnosed with right upper lobe lung adenocarcinoma, cT4N3M1c, cStage IVB (BRA, LYM, ADR, OTH; esophagus and duodenum) (UICC-9th edition) with pulmonary lymphangitic carcinomatosis.Treatments included corticosteroid administration, stereotactic brain irradiation, and percutaneous endoscopic gastrostomy. While the respiratory symptoms temporarily improved, then eventually worsened. Forty days after the first visit, the patient died due to respiratory failure.A pathological autopsy was performed. The right upper lobe tumor consisted of poorly differentiated adenocarcinoma (Figure 3A, upper right). The lymphatic vessels throughout the lungs were enlarged and filled with adenocarcinoma cells, and the stroma surrounding these vessels also contained tumor cells (Figure 3A, lower right). In the esophagus, duodenum, and jejunum, carcinomatous cells were found in all layers, including the lymphatic vessels, while the wall structure was preserved (Figure 3B, C). Apart from the lung and upper gastrointestinal tract, adenocarcinoma was diffusely present in the stroma around the thyroid follicles (Figure 3D), cervical tissue, lymph nodes, pericardium, myocardium (Figure 3E), and adrenal glands (Figure 3F).DiscussionLymphangitic carcinomatosis is a form of metastatic disease characterized by the diffuse spread of malignant tumors through the lymphatic system, which is associated with poor prognosis.1 The pathophysiology is not well understood; however, direct invasion, lymphatic circulation, and hematogenous spread are considered to be possible pathways.2 In this case, adenocarcinoma was detected in the lung, thyroid, pericardium, myocardium, esophagus, duodenum, jejunum, adrenal glands, and brain. Except for the brain, the other cancerous sites were anatomically contiguous. The presence of tumor cells in the lymphatic vessels and stromal tissues suggested that the predominant routes of cancer dissemination in this patient was direct lymphatic invasion. This case is novel as it demonstrates pulmonary lymphangitic carcinomatosis alongside extensive mediastinal, retroperitoneal, and upper gastrointestinal tract invasion, a presentation not commonly associated with lung cancer.AcknowledgementsWe thank Editage (www.editage.com) for the English language editing.References1. Klimek M. Pulmonary lymphangitis carcinomatosis: Systematic review and meta-analysis of case reports, 1970-2018. Postgrad Med . 2019;131(5):309-318. doi: 10.1080/00325481.2019.1595982.2. Al-Bayati M, Al-Jobory O, Abu-Hassan F, Mohammed BU, Yaqoob S, Bazzaz O. Pulmonary lymphangitic carcinomatosis: An atypical presentation leading to discovery of multi-organ metastasis with unknown occult primary malignancy. Cureus . 2022;14(8):e27705. doi: 10.7759/cureus.27705