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 9 kg (20 lb) over the last 4 months. He is a former smoker, having stopped 25 years ago after a 20-pack-year history. There is no notable family history. Physical examination reveals cachexia, palpable non-tender 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 tumour 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 pathological fracture with bony involvement; localised swelling, if superficial lymph nodes are involved; obstructive jaundice due to pancreatico-biliary lesions; and post-obstructive pneumonia or haemoptysis 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 localising symptoms, patients often report a non-specific 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.