A Rare Case of Colonic Squamous Cell Carcinoma Metastasis Originating From Adenosquamous Cell Carcinoma of the Lung

Document Type

Conference Proceeding

Publication Date

10-25-2023

Publication Title

Am J Gastroenterol

Abstract

Introduction: Gastrointestinal metastasis from lung cancer is a rare occurrence, and colonic involvement is particularly uncommon. This case report highlights the importance of considering gastrointestinal metastasis in lung cancer patients and emphasizes the role of histopathological and immunohistochemical investigations in achieving an accurate diagnosis. Case Description/Methods: A 69-year-old man with a significant smoking history was incidentally diagnosed with right upper lobe (RUL) lung adenocarcinoma during evaluation for stroke-like symptoms. Several weeks later, the patient experienced a significant drop in hemoglobin levels, leading to gastroenterological evaluation. Colonoscopy revealed multiple nodules throughout the colon. Biopsy of the ascending colon nodule confirmed metastatic poorly differentiated squamous cell carcinoma, supported by immunohistochemical examination (Figure 1). Brain MRI also showed evidence of metastatic disease. Considering the patient's TPS score of >50%, palliative therapy with pembrolizumab monotherapy was initiated following whole brain radiation treatment. Discussion: Lung cancer is a leading cause of cancer-related deaths, often resulting in distant metastasis to organs such as the brain, liver, adrenal glands, and bone marrow. Gastrointestinal metastasis, particularly in the colon, is rare but can be misdiagnosed as primary gastrointestinal tumors. Accurate diagnosis requires histopathological examination and immunostaining. The incidence of gastrointestinal tract metastases from the lung is increasing due to improved early detection and advancements in cancer treatment. However, there is a lack of well-established treatment guidelines for these cases, and management should be individualized through a multidisciplinary approach. The time interval between the diagnosis of primary lung cancer and gastrointestinal metastases can vary, ranging from 2 weeks to 4 years. Therefore, clinicians should remain vigilant even after the initial cancer treatment. Despite the generally poor prognosis associated with metastatic lung cancer, maintaining a high index of suspicion for gastrointestinal involvement in lung cancer patients with gastrointestinal symptoms and adopting a systematic diagnostic approach can lead to early detection, appropriate management, and improved quality of life. Further research is needed to better understand the underlying mechanisms and optimize treatment, considering the impact of prior therapies on prognosis and anti-cancer efficacy.

Volume

118

Issue

10

First Page

S1624

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