Rare Case of Rectal Metastasis from Primary Lung Adenocarcinoma Reported in New Research

Strategic Insights -

Research published in the World Journal of Surgical Oncology has detailed a rare case of rectal metastasis from an EGFR L858R-mutant primary lung adenocarcinoma. The study describes a 79-year-old male patient who presented with worsening constipation, which led to the discovery of a rectal mass. Initial biopsies revealed chronic rectal mucosal inflammation, but subsequent imaging and immunohistochemical analysis confirmed rectal metastasis from primary lung adenocarcinoma. The patient received treatment with aumolertinib mesilate tablets and palliative radiotherapy.

Key Takeaways:

  • Non-small cell lung cancer (NSCLC) accounts for approximately 80% of all lung cancers, and 40% of patients with lung cancer present with distant metastases at diagnosis.
  • Symptomatic rectal metastasis from primary lung adenocarcinoma before the onset of lung symptoms is exceedingly rare.
  • The patient in this case presented with worsening constipation, which led to the discovery of a rectal mass.
  • Initial biopsies revealed chronic rectal mucosal inflammation, but subsequent imaging and immunohistochemical analysis confirmed rectal metastasis from primary lung adenocarcinoma.
  • The patient received treatment with aumolertinib mesilate tablets and palliative radiotherapy.
  • Clinicians should have a low threshold for pulmonary low-dose spiral CT to diagnose rectal metastasis from primary lung adenocarcinoma.
  • Histopathologic analysis by immunohistochemistry combined with molecular diagnostics is critical for timely and accurate diagnosis and to distinguish rectal metastases from primary rectal malignancies.
  • The case highlights the importance of considering rare presentations of lung cancer and the need for clinicians to be aware of the possibility of rectal metastasis from lung cancer.

Statistics:

  • 80% of lung cancers are non-small cell lung cancer (NSCLC).
  • 40% of patients with lung cancer present with distant metastases at diagnosis.
  • The patient in this case was 79 years old.
  • The patient presented with worsening constipation, which progressed to dyspnoea, cough, expectoration, bilateral lower limb weakness, and poor appetite.
  • The patient received treatment with aumolertinib mesilate tablets and palliative radiotherapy.

Sources:

  • NewsRx. Research Conducted at Shanghai Biotecan Pharmaceuticals Co. Ltd. Has Updated Our Knowledge about Lung Cancer (Rectal metastasis as the initial presentation of primary lung adenocarcinoma with an EGFR L858R mutation: a case report). China Weekly News. October 21, 2025; p 394.
  • Rectal metastasis as the initial presentation of primary lung adenocarcinoma with an EGFR L858R mutation: a case report. World Journal of Surgical Oncology, 2025;23(1):362.