Does the size of the tumour matter? Case study of kidney cancer & BHD

In this blog, we discuss a recent report detailing an interesting clinical case of a patient who was treated for a small tumour on her kidney. Although the patient had no family history of pneumothorax or kidney cancer, the patient was tested for and diagnosed with BHD syndrome. We also look at why genetic testing for BHD syndrome is so important in these clinical cases.

Presenting complaint and diagnosis

A 53-year-old woman presented in clinic complaining of back pain. To determine the cause of this problem, the doctors conducted an examination and tests including a CT scan. A CT scan is a test that takes detailed pictures of the inside of your body. A tumour smaller than 3cm was found. A tumour is an abnormal mass of tissue and it can be cancerous or non-cancerous. In this patient, this mass of tissue was found on the kidney.

Surgery as a form of treatment

Treating kidney cancer is important, because it can help prevent progression of the condition. For this patient, doctors initially did a partial nephrectomy. Nephrectomy is a type of surgery that removes all or part of a kidney. This patient had a part of her kidney removed. However, after surgery, there were some remaining areas that were not free of tumour. As a result, the clinicians did a radical nephrectomy. This is a type of surgery that removes the entire kidney, as well as the fat surrounding it.

Six years on

The patient was followed-up for the purpose of monitoring her condition and identifying any new disease. After six years, when the patient had reached 59 years old, an abdominal CT revealed six omental metastases. Omental metastases refer to the spread of cancer cells to the omentum. This is a double layer of fatty tissue that covers and supports the intestines and organs in the lower abdomen. The omentum plays a role in immune response and fat storage. The patient had no lesions on the kidney, and the omental lesions were considered metastases from the primary tumour found 6 years ago. Metastases refer to the spread of cancer cells from the original site to other parts of the body. 

Immunotherapy as a form of treatment

The patient then received immunotherapy. This is a type of treatment that activates or suppresses the immune system. Immunotherapy helps the immune system fight the cancer. Despite this form of treatment, the metastases had progressed on a minimal level.

Taking a closer look

The clinicians looked at the family history. The family members showed no evidence of kidney cancer and pneumothorax. Later, the patient was examined physically. The doctors found small skin bumps. These skin bumps were subtle on the face, but they were more prominent in the neck, chest and abdomen. The patient then received genetic testing. This confirmed a diagnosis of BHD.

What can we learn from this case of BHD?

Although the patient had received treatment for her condition, there was no diagnosis of a pre-existing condition that the patient was living with. Only after genetic testing, the patient learnt that she had BHD. This highlights the importance of genetic testing. A genetic test has a crucial role to play as it can help patients receive the correct diagnosis. This can influence treatment options and other aspects such as how often the patient is screened.

The authors in this paper call for more extensive research that involve large groups of people living with BHD to study the behaviour of small kidney tumours in these patients. This patient had a tumour of 2.8cm, and this case reveals the importance of not underestimating the spreading potential of smaller tumours. At the moment, there is a lack of data on tumours smaller than 3cm that have spread to other sites in the body. More research in this area can help lead to a better understanding.

Overall, it is critical that to have such cases reported as it can help researchers, clinicians and patients have a more informed understanding of BHD, complications that may arise, and treatment options. 

Reference:

1. van Riel, L., Kets, C.M., van Hest, L.P. et al. Metastatic disease after removal of a renal cell carcinoma smaller than 3 cm in a patient with Birt-Hogg-Dubé syndrome, a case report. Familial Cancer (2024). https://doi.org/10.1007/s10689-024-00408-w