Adenocarcinoma of unknown primary site

Case history

A 72-year-old man presents with early satiety, vague right upper quadrant pain, and progressive fatigue. He has no significant medical history, but has lost approximately 20 lb (9 kg) over the last 4 months. He is a former smoker, having quit 25 years ago after a 20-pack-year history. There is no notable family history. Physical exam reveals cachexia, palpable nontender hepatomegaly, and dullness to percussion to the right lung base.

Other presentations

The clinical presentation of adenocarcinoma of unknown primary site (ACUP) is typically related to the sites of tumor involvement, which are often multiple, and typically include the liver, lungs, lymph nodes, and bones.

Presenting signs and symptoms commonly include pain, from peritoneal or pleural irritation, or pathologic fracture with bony involvement; localized swelling, if superficial lymph nodes are involved; obstructive jaundice due to pancreaticobiliary lesions; and postobstructive pneumonia or hemoptysis with parenchymal lung involvement. Less common signs and symptoms include depression, delirium, seizures, headache, ascites, a palpable mass, and neuropathic pain or weakness.

In conjunction with localizing symptoms, patients often report a nonspecific deterioration in their overall health, with poor appetite, weight loss, fatigue, and weakness predominant. Such symptoms tend to be progressive, and lead to a decline in performance status and decreased ability to tolerate recommended treatments.

Subsets of patients with ACUP exhibit specific presenting features that can indicate a likely primary site and guide treatment accordingly.