Inguinal Lymphadenopathy: A Rare Initial Site of Metastatic Lung Carcinoma

Solid-organ tumors involving inguinal lymph nodes commonly originate from genitourinary tract, skin, ano-rectum, or the urinary bladder. Thus, solitary metastatic involvement of inguinal lymph nodes from extra-abdominal primary malignancies is extremely rare. However, involvement of nonregional lymph nodes upstages the disease to M1b with poor prognosis. Identification of the site of metastases is extremely crucial for deciding the management of patients. This is the first ever case reported of de-novo or synchronous oligometastatic disease of carcinoma lung with inguinal lymph node involvement. In addition, it highlights the importance of ¹⁸ FDG PET-CT to diagnose the involvement of inguinal lymph node that was further proved on fine needle aspiration cytology. Only two such cases of lung cancer have been reported, but both of them had inguinal lymph node during the follow-up and none was present at initial presentation.