Case Report Suggests Thymus May Play Role in Sarcoidosis Development in Some Patients

Abnormal thymus growth may cause sarcoidosis in certain patients, a case report recently demonstrated. As immune T-cells mature in this lymph organ, researchers suggest that an enlarged thymus may signal the presence of autoimmune processes in some cases.

The study, “Recovery of pulmonary and skin lesions of sarcoidosis after thymectomy,” was published in the journal Acta Clinica Belgica: International Journal of Clinical and Laboratory Medicine.

Researchers at Hacettepe University in Turkey described the case of a 53-year-old woman who had hard lumps under the skin surrounding one eye, one hand, and one foot. She also had red lumps on her legs.

When admitted to the hospital, routine lab tests, lung function tests, and heart exams were all normal. Computed tomography (CT) of her chest showed that lymph nodes in the chest and lungs were enlarged. Physicians also noted a lesion in the woman’s thymus, which is located behind the sternum and between the lungs. The thymus produces disease-fighting T-cells until puberty, then slowly starts to shrink.

Tissue samples showed the lesions held sarcoidosis-type granulomas, and the patient started treatment with the corticosteroid prednisolone. During the eight months of treatment, the skin nodules improved, but the woman chose to stop the treatment because of associated side effects.

Since she had no lung symptoms, and the skin lesions did not bother her, she decided against taking other drugs.

Meanwhile, doctors decided it would be wise to remove the thymus. An enlarged thymus does not always indicate that disease is present, but considering the woman’s other symptoms, a multidisciplinary team believed the thymus lesion could be linked to sarcoidosis. An analysis of the organ after the surgery confirmed that it was enlarged.

Six months after surgery, and with no further drug treatment, the skin lesions had disappeared, and the enlarged lymph nodes had improved.

The research team noted that there has been only one similar case described — with sarcoidosis linked to an enlarged thymus — in the scientific literature. There are also some rare cases where sarcoidosis could be linked to the presence of tumors in the thymus.

In another condition with autoimmune causes — myasthenia gravis — thymus removal often improves symptoms, particularly in patients with enlarged organs.

Together, these observations led the research team to suggest the thymus may be linked to sarcoidosis development in a subgroup of patients.

The team concluded, “in this report, the remission of skin and pulmonary sarcoidosis lesions occurred only after thymectomy. This finding potentially indicates the critical role that the thymus might play in the pathogenesis of this disease in a certain group of patients.”