When your joint pain might be a hidden cancer: The deadly link between rheumatic symptoms and tumors

Regrettably, deceptive situations occur where rheumatology specialists treat patients suffering from symptoms that resemble rheumatic diseases. In reality, the patients may be battling an undiagnosed malignant disease posing a direct threat to their lives.

Precancerous syndromes can mimic rheumatic disease symptoms

Some tumours can produce symptoms that remarkably resemble those of rheumatic diseases. This can lead to errors in diagnosis. There are instances where tumours can cause rheumatic diseases, referred to as paraneoplastic syndromes. These can manifest before or during the diagnosis of a tumour.

Malignant diseases can also mask rheumatic diseases. Numerous symptoms indicate the possibility of dermatomyositis, where patients experience weaknesses in the proximal shoulder and pelvic muscles, and a rash around the eyes, among other symptoms. During diagnostics towards a rheumatic disease, it may transpire that the patient has lung cancer. This is referred to as a paraneoplastic syndrome, presenting symptoms that affect organs or systems not directly impacted by the tumour, suggesting the presence of another disease entity – explains Bartosz Fiałek, a rheumatologist in an interview with WP abcHealth.

Following successful treatment of the tumour, these symptoms may completely dissipate, which is atypical for rheumatic diseases. Dr. Katarzyna Muras-Szwedziak emphasizes the importance of knowledge about rheumatological paraneoplastic syndromes as it can potentially save lives.

Difference between rheumatic disease and paraneoplastic syndrome

It is impossible to differentiate a specific rheumatic disease from a paraneoplastic syndrome without comprehensive diagnosis. This diagnosis must consider malignant diseases as well. In cases of increased cancer risk, the doctor should always approach with caution, as this can save the patient's life – adds the rheumatologist.

Rheumatological diseases elevating cancer risk

The rheumatology expert discusses which rheumatological diseases can elevate the risk of cancer. Polymyalgia rheumatica, an inflammatory disease, is one of these. Patients with this disease often coexist with a tumour, demonstrating both cancer and rheumatic disease symptoms.

Other rheumatological diseases that can increase cancer risk include polymyositis and dermatomyositis. Polymyositis is indicated by progressive weakening of the proximal limb muscles. Conversely, in dermatomyositis, skin symptoms accompany muscle symptoms.

- I once treated a patient who presented with progressive muscle weakness and a dry cough. No signs of muscle inflammation were detected during diagnostic processes, however, lung cancer was detected. In this case, the symptoms were attributed to the malignant disease, not polymyositis - explains the doctor.

He emphasizes the significance of imaging tests in diagnosing tumours. Among these tests are X-rays, ultrasonography, computed tomography, and magnetic resonance imaging.

- In cases where specific rheumatic antibodies are not present in the patient and imaging tests do not show changes typical for rheumatic diseases, a visible lung tumour confirms the diagnosis of lung cancer, exhibiting symptoms of a specific rheumatological disease - he explains.

Non-negligible symptoms

Doctor stresses that early detection of paraneoplastic syndrome is potentially life-saving. It's crucial to look out for nonspecific symptoms that usually emerge in the early stages of malignant diseases.

- I once treated a patient who came to me due to suspected bone mineralization disorders. I noticed he had clubbed fingers, which may be a symptom of lung cancer. After further diagnostics, lung cancer was indeed confirmed - he explains.

Alongside rheumatoid paraneoplastic syndrome, hormonal, neurological, and hematological paraneoplastic syndromes are also identified. He underlines that an unclear clinical picture could be a symptom of a malignant disease. Maintaining oncological alertness for early diagnosis and a better prognosis is essential.

- It is relatively infrequent for a tumour to mask another disease syndrome, but it's not rare enough to be treated as case studies. A lot depends on the nature of the symptoms and the patient's clinical condition - adds the expert.