肺癌在台灣的發生率逐漸增加，其中「肺腺癌」比例最高，早期診斷與治療可顯著改善預後。然而，肺腺癌可能以不典型表現出現，例如影像學上呈現粟粒狀分布病灶。本文報告一位79歲女性因咳嗽超過一個月就診，胸部X光顯示雙側肺部瀰漫性結節。進一步檢查發現右下肺有8.2公分腫瘤，伴隨肺內轉移及淋巴結腫大，病理診斷為肺腺癌。粟粒狀病灶的常見鑑別診斷包括感染性疾病（如粟粒型結核）及腫瘤轉移（如甲狀腺癌、腎癌、肺腺癌等等），需要藉由胸部高解析度電腦斷層檢查來分別。<p>本案例提醒，若病人出現相關呼吸道症狀（如咳嗽、胸痛或呼吸困難）、或伴隨體重減輕、疲勞、食慾不振等等全身性症狀，並且影像呈現粟粒狀病灶，需考慮肺腺癌的可能性。咳嗽、呼吸喘皆是基層醫療很常見的症狀，而「肺腺癌」也可能以這些症狀來表現，而且容易被延誤診斷。因此家庭醫學科醫師必須對「肺腺癌」的診斷有更高的警覺性，進行詳細的病史詢問，並對於懷疑腫瘤的病人安排相關影像學檢查，以期改善病人預後。

Lung cancer incidence in Taiwan has been rising, with adenocarcinoma being the most prevalent subtype. While early diagnosis and treatment significantly improve prognosis, atypical presentations such as miliary patterns on imaging can post diagnostic challenges. We report the case of a 79-year-old female patient who presented with a chronic cough lasting over one month. Chest X-ray revealed diffuse bilateral pulmonary nodules. Subsequent imaging identified an 8.2 cm tumor in the right lower lung, along with intrapulmonary metastases and lymph node enlargement. Histopathology confirmed the diagnosis of lung adenocarcinoma. The differential diagnosis of miliary lung lesions typically includes infectious diseases such as miliary tuberculosis, as well as metastatic malignancies, including thyroid cancer, renal cancer, and lung adenocarcinoma. High-resolution computed tomography of the chest is often essential for distinguishing among these conditions. <p> This case underscores the importance of considering lung adenocarcinoma in patients presenting with chronic respiratory symptoms and miliary patterns on imaging. Symptoms such as cough and dyspnea are frequently encountered in primary care settings, and lung adenocarcinoma may manifest through these nonspecific symptoms, potentially leading to delayed diagnosis. Family physicians should therefore maintain a high index of suspicion for lung adenocarcinoma to ensure timely diagnosis and improved patient outcomes.