Adenocarcinoma of unknown primary site

Last reviewed: 29 Apr 2022
Last updated: 24 May 2018

Summary

Definition

History and exam

Key diagnostic factors

  • bone pain
  • FHx of cancer
More key diagnostic factors

Other diagnostic factors

  • jaundice
  • ascites
  • personal hx of previous cancer
  • hx of smoking
  • pain
  • palpable mass
  • symptoms of postobstructive pneumonia
  • neurologic pain or weakness
  • headaches
  • seizures
  • cervical chain adenopathy
  • constitutional symptoms
  • depression
  • delirium
  • hx of heavy alcohol consumption
  • hepatomegaly
  • hemoptysis
Other diagnostic factors

Risk factors

  • age >60 years
  • black ancestry
More risk factors

Diagnostic investigations

1st investigations to order

  • CXR
  • CT (chest, abdomen, pelvis)
  • mammography
  • MRI of breast
  • transvaginal ultrasound
  • diagnostic paracentesis
  • upper aerodigestive panendoscopy (for patients with isolated cervical adenopathy)
More 1st investigations to order

Investigations to consider

  • colonoscopy (for patients with resectable liver metastases)
  • light microscopy, with hematoxylin and eosin (H&E) staining
  • immunohistochemical (IHC) markers
  • estrogen and progesterone receptor status
  • serum tumor markers
More investigations to consider

Emerging tests

  • positron emission tomography (PET)
  • gene expression profiling

Treatment algorithm

INITIAL

identification of primary site pending

ACUTE

>1 metastasis: favorable clinicopathologic subtype not identified

>1 metastasis: women with isolated axillary lymphadenopathy (likely primary: breast)

>1 metastasis: women with peritoneal carcinomatosis (likely primary: ovarian)

>1 metastasis: with neuroendocrine features

>1 metastasis: poorly differentiated adenocarcinoma of the midline

>1 metastasis: likely prostate primary

single metastasis

Contributors

Authors

Ross C. Donehower, MD, FACP

Director

Division of Medical Oncology

Johns Hopkins University School of Medicine

Baltimore

MD

Disclosures

RCD declares that he has no competing interests.

Acknowledgements

Dr Ross C. Donehower would like to gratefully acknowledge Dr David Cosgrove and Dr Hatim Hussain, previous contributors to this monograph. DC and HH declare that they have no competing interests.

Peer reviewers

Nikhil Khushalani, MD

Assistant Professor

Department of Medicine

Roswell Park Cancer Institute

Buffalo

NY

Disclosures

NK declares that he has no competing interests.

Zelig Tochner, MD

Associate Professor

Radiation Oncology

Children's Hospital of Philadelphia

Philadelphia

PA

Disclosures

ZT declares that he has no competing interests.

Justin Stebbing, MA, MRCP, MRCPath, PhD

Consultant Medical Oncologist/Senior Lecturer

Department of Medical Oncology

Imperial College/Imperial Healthcare NHS Trust

Charing Cross Hospital

London

UK

Disclosures

JS declares that he has no competing interests.

  • Adenocarcinoma of unknown primary site images
  • Differentials

    • Squamous or neuroendocrine carcinoma of unknown primary
    More Differentials
  • Guidelines

    • NCCN clinical practice guidelines in oncology: occult primary
    • NCCN Clinical Practice Guidelines in Oncology: occult primary
    More Guidelines
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