Introduction
Lung and bronchus cancer is the third leading cancer in the United
States (US) and was the leading cause of cancer death in
2019.1 Deaths from lung and bronchus cancer also
accounted for 23% of all deaths related to cancer.2Lung cancer is split up into four major types of lung cancer that
account for 88% of primary lung cancer; adenocarcinoma, squamous cell,
small cell, and large cell, listed in descending
order.3 These non-small cell lung cancers (NSCLC)
makes up the majority of all lung cancers, however presentations of
these cancers range from a peripheral nodule, central mass, to widely
disseminated disease.3 The presentation of lung cancer
can sometimes be easily seen when incidentally found on imaging, other
times it is more subtle, like when presenting as a Paraneoplastic
syndrome. These syndromes can present as hypercalcemia (squamous cell),
SIADH (small cell), gynecomastia (large cell), or even connective tissue
syndromes such as clubbing and hypertrophic osteoarthropathy (HOA) which
are both most often associated with NSCLC.20
In this article, we describe a patient who experienced joint pain in her
hands and pain in one knee, which later progressed to her other leg. She
was ultimately found to have NSCLC of squamous origin. A thorough
literature review on NIH Database has shown multiple case studies that
show the correlation between NSCLC and HOA involving large joints.
However, there are limited reports of singular joint involvement with
later progression to other joints. One case report showed a patient with
NSCLC who had 2 weeks of acute joint pain in all four extremities,
including his hands, fingers, knees, and ankles and was found to have
adenocarcinoma.4 Another retrospective study by
Cantini and associates did a study from the years 2000 to 2005 which
included patients with isolated knee monoarthritis as the initial
presenting sign.5 The study eventually found that five
out of 296 patients with isolated knee monoarthritis were found to have
NSCLC.5 This conclusion was again demonstrated in 2020
by a case report involving monoarthritis in the knee, a presenting sign
of HOA associated with NSCLC. However, the patient evaluated in this
article shows that this monoarthritis could spread to other joints,
which emphasizes the importance of watching for spreading arthropathies
as a presenting symptom of NSCLC and how surgery could be the definitive
treatment.