Rare case of acute appendicitis due to metastatic lung cancer detected

Accordingly, at the end of August, Mr. NSC (75 years old, Quan Bau Ward, Vinh City, Nghe An) experienced pain in the lower abdomen; then, it spread to the pelvis. When taken to the district hospital for emergency treatment, he was diagnosed with acute appendicitis, and doctors performed surgery to remove the appendix.

After surgery, the patient's specimen was sent for testing at Nghe An Oncology Hospital. The results of pathology and immunohistochemistry of the specimen showed that the appendix was consistent with metastasis of lung adenocarcinoma (i.e. lung cancer metastasized to the appendix).

It is known that Mr. NSC is a special patient because both he and his wife have late-stage lung cancer and are being treated at the Department of Internal Medicine II - Nghe An Oncology Hospital. In September 2023, he was admitted to the hospital with frequent shortness of breath, chest pain, severe cough, fatigue, and was diagnosed with stage IV lung cancer with metastasis to the abdominal lymph nodes.

Due to his frail health and severe chronic obstructive pulmonary disease, he was advised by doctors and ordered to undergo gene mutation testing. Fortunately, the results detected a drug-sensitive gene mutation, he was consulted by a multidisciplinary team and decided to take daily oral targeted therapy for over a year now.

During the treatment, the patient had a spectacular response. The lung tumor, which was about 7cm in size before treatment, has now disappeared, leaving only fibrotic bands; there are no more abdominal lymph nodes. His health has also improved significantly. Previously, Mr. C often had chest pain, difficulty breathing, and difficulty taking care of himself. Up to now, he has recovered from the above conditions, has a better appetite, and has gained 2 kg; his quality of life and spirit have improved.

According to Dr. Nguyen Khanh Toan - Head of Internal Medicine II, Nghe An Oncology Hospital, lung cancer is one of the malignant diseases and the second leading cause of death after liver cancer in Vietnam. The most common metastatic sites of lung cancer are lymph nodes, brain, liver, bones and adrenal glands... Appendiceal metastasis is a very rare metastatic site of primary lung cancer with a reported frequency of about 5/1,000,000.

The metastatic pathways of lung cancer to the appendix include lymphatic or hematogenous metastasis, and metastatic foci are formed in the submucosal or muscular layer. However, it often causes acute appendicitis requiring emergency surgery due to the risk of perforation of the appendix, which can lead to peritonitis or widespread metastasis in the abdomen, threatening the patient's life.

In Mr. C's case, after appendectomy and the appendix was determined to be a metastatic organ originating from the lung, the doctors re-evaluated and re-screened the primary lung tumor, the location of the metastasis and the organs did not detect any abnormalities. He was consulted to continue targeted treatment along with close monitoring by doctors from the Department of Internal Medicine II - Nghe An Oncology Hospital.

Mr. NSC is a rare case of metastatic lung cancer presenting as acute appendicitis following appendiceal metastasis. This reminds us of the various complications of metastatic lung cancer and physicians should be aware of the differential diagnosis of acute appendicitis as this may be due to secondary metastasis.