Metastatic Anaplastic Lymphoma Kinase Rearrangement-Positive Adenocarcinoma of Occult Primary Mimicking Ovarian Cancer.

Lung cancer is a worldwide concern and is the leading cause of cancer-related death in the United States. Adenocarcinoma is the most common type of non-small cell lung cancer; however, unlike other types of lung cancer this disease is often seen in light tobacco smokers and non-smokers. The presence of driver mutations, such as the epidermal growth factor receptor (EGFR) and echinoderm microtubule-associated protein-like 4 (EML-4)-anaplastic lymphoma kinase (ALK) rearrangement, appears to be more common in these patients. The presence of the ALK mutation provides a target for ALK-inhibiting agents, such as alectinib. Routine testing for driver mutations is the standard of care in the management of advanced non-small cell lung cancer. Lung cancer frequently metastasizes to distant sites such as the bone, brain, and the adrenal glands, but rarely to the ovaries. We present a young, female, patient who complained of shortness of breath and was found to have pulmonary emboli, extensive lymphadenopathy, and a right ovarian mass. Initial pathology from a cervical lymph node favored a gastrointestinal or an ovarian malignancy. However, immunohistochemical staining ultimately suggested an occult lung adenocarcinoma primary with ovarian metastasis. She had a left oophorectomy that demonstrated similar findings and was positive for the ALK mutation. She was treated with alectinib with good response though ultimately died from her disease. This case demonstrates the rare finding of an ALK-mutated lung adenocarcinoma with ovarian metastasis and, to our knowledge, it is the first with an occult lung adenocarcinoma primary. Driver mutation testing should be considered in metastasis from an occult primary when a pulmonary malignancy is suspected.